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E.
Ear.
A small projection on an object, usually for support or attachment; as: —
1. The
ear of a bucket or cooking-pot to which the bail is attached.
The
car or
leg of a sugar or salt boiling kettle by which it is supported on the walls of the furnace.
The ear of a shell is imbedded in the metal, and serves for inserting the hooks by which the projectile is lifted.
2. (
Music.) In the metallic mouth-pipe of an organ; one of the pair of soft metal plates at each end of the slit or mouth of the pipe, which may be bent more or less over the opening, to qualify the tone.
3. The
canon of a bell, the part by which it is suspended.
4. (
Printing.) A projection on the edge of the frisket; or one on the edge of the composing-rule.
5. The loop or ring on the ram of a pile-driver by which it is lifted.
6. One of the two projecting parts on the portions of an eccentric strap by which they are bolted together.
Ear, Arti-fi′cial.
An auricle having the shape of the natural ear, and worn as an ear-trumpet, to collect the waves of sound and conduct them by a tube to the
meatus auditorius. Usually made of gutta-percha colored to resemble nature, and attached by clasps to the natural ear. See auricle.
Ear-brush.
A toilet instrument for cleaning the ear. A bulb of sponge on a handle.
An
aurilave.
Ear-cor′net.
A small auricle which is contained within the hollow of the outer ear and has a short tube to keep open the
meatus auditorius in cases of contraction or the presence of polypi.
An
eartrumpet.
E-lec′tro-mag-netic Bat′ter-y.
One in which the current is generated in the voltaic battery, as distinguished from the
electric, the
magneto-electric, or the
thermal battery.
Ear′ing.
（
Nautical.) The rope which lashes the upper corner of a sail to its yard.
The
reef-carings are used to lash the ends of the reef-band to the yard.
Ear of Dio-nys′i-us.
An acoustic instrument named after the sound-conducting orifice in the roof of the dungeons where the old Sicilian tyrant kept his prisoners.
It has a large mouth-piece to collect the sound, which a flexible tube conducts to the ear of the person.
It is especially adapted for enabling the very deaf to hear general conversation, lectures, sermons, etc. See acoustic instruments.
Ear-pick.
（
Surgical.) A small scoop to extract hardened cerumen from the
meatus auditorius, or foreign matters from the external ear.
Ear-spec′u-lum.
（
Surgical.) An instrument for distending the exterior canal of the ear, in removing indurated wax, or other explorations and operations.
An
otoscope.
Ear-syr′inge.
An instrument for injecting the ear with a liquid or medicated vapor.
An ordinary syringe may answer the usual purposes of cleanliness, softening indurated wax, etc., but the instrument shown has a farther capacity.
a is an indiarubber air-bag,
b a flexible tube,
c a bulb of hardrubber, made in two pieces, which screw together and contain a sponge to hold chloroform or other liquid;
d is the perforated bulb.
It is particularly used in treating diseases of the middle ear. The sponge being previously moistened, the nozzle of the bulb is placed in one nostril, the other is closed by the finger of the surgeon, the mouth is also closed, and the patient, having previously taken a mouthful of water, is told to swallow, and, just as he is doing this, the surgeon compresses the air-bag, and sends the iodized air into the faucial orifice of the eustachian tube, and, if the drum be perforated, into the cavity of the tympanum.
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Roosa ear-syringe. |
Earth.
（
Telegraphy.) The ground in its relation to the circuit as the means of conducting the return current.
The conductor is led to a buried ground-plate or to a gas or water main, which forms an admirable ground conductor.
Earth-bat′ter-y.
A large plate of zinc and a plate of copper, or a quantity of coke, buried at a certain distance asunder in damp earth.
The moisture of the earth acts as the exciting fluid on this voltaic couple, and a feeble but constant current is produced.
Earth-board.
The mold-board of a plow.
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Earth-borer. |
Earth-bor′er.
A form of auger for boring holes in the ground, where the strata are sufficiently soft and loose.
The shaft has a screw-point and a cutting-face.
The twisted shank revolves inside a cylindrical case, which retains the earth till the tool is withdrawn.
The valve opens to admit the earth, and closes as the tool is lifted.
See auger.
Earth-car.
A car for transporting gravel and stone in railway operations.
See Dumpingcar.
Earth-clos′et.
A commode or night-stool in which a body of earth receives the feces, or is dropped upon them to absorb the effluvia; the resultant is to be utilized as a fertilizer.
A is a pan provided with an absorbent; when full, the lining and the contents are removed and buried, and another lining of earth placed in the pan by packing around the mold
B.
C has a seat
a, which descends with the person and brings a charge of earth in readiness to fall upon the feces.
As the person rises, the quantity of earth released by the former operation is dropped upon the feces in the pan below.
b is the earth reservoir, and
c the dumping-spout.
Earth′en-pipe.
The
Romans used earthen pipes where economy was an object.
They preferred lead.
The earthen pipes had a thickness of at least two inches, and the ends were respectively contracted and enlarged to fit into and to receive the
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adjacent pipes.
The joints of the pipes were luted with quicklime and oil. The thickness was increased at the bottom of a bend, as in crossing a valley or hollow, or the pipe at this part was “secured by ligatures or a weight of ballast” (Vitruvius). Earthen pipes are found in the walls of the baths and the Coliseum, of various diameters, none less than 2 inches diameter.
The elaborate arrangement of pipes in the amphitheater of Vespasian has probably never been excelled.
Fifty-six drains constructed within the thickness of the walls which supported the staircases of the ground-floor served to carry off the rainwater which fell in the building, and also the contents of the urinals in the third and fourth stories.
The drains were cylindrical pipes of 12 inches diameter, hollowed out of freestone blocks 20 inches in hight.
The drains were led down from the upper stories through pipes in the masonry of the stairs, and united with hundreds of other drains at the larger conduits, which conducted the water to the
Cloaca Maxima.
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Earth-closets. |
The arrangement of the aqueduct and distributing pipes which conducted the water from the fountain of
Nismes was as elaborate as the emunctories described.
See “
Cresy,” ed. 1865, pp. 108-118.
Earth′en-ware.
A general expression which covers all ceramic work, such as
stone-ware, delft, porcelain, etc. See pottery. The term, as far as it may have a less general meaning, includes merely the commoner classes of clay-ware, otherwise known as
crockery.
The clay, having been properly tempered, is formed on the wheel and dried under cover until it has acquired considerable solidity.
The glaze, of the consistence of cream, is then put on as evenly as possible by means of a brush.
Small articles are glazed by pouring in the glaze and then pouring it out again, sufficient adhering for the purpose.
The glaze consists of galena ground to powder and mixed with “slip” ; that is, a thin solution of clay.
This is a clear glaze, and is made black and opaque by the addition of manganese: galena, 9; manganese, 1 part.
The glaze having dried, the ware is piled in the kiln.
A low heat, applied for twenty-four hours, drives off the moisture; an increased heat for another twenty-four hours, as high as can be borne without fusion, bakes the clay, drives off the sulphur from the galena, and causes the lead to form a glass with the clay to which it adheres.
With increase of heat this glass spreads over the surface of the ware.
After the furnace is cooled, the ware is removed.
The glaze, consisting of oxide of lead, is soluble in acids, such as vinegar and those of fruit, and is destroyed, rendering injurious the food with which it combines.
A more refractory clay admits the use of a less fusible glaze of a harmless character.
Earthen-ware is found among almost all nations and tribes, though not all have the art of glazing, nor have all the art of baking.
Drying is not
baking, and it requires a good heat to make a good ringing article.
The
Egyptians and
Etruscans had pottery at a date before the historic period.
We know more of the former than of the latter at early periods.
The resemblance of the Greek and Etrurian ceramic works is remarkable.
Glazing came from
China.
Wedgwood's patents about 1762.
See specific list under pottery and clay.
Earth-plate.
（
Telegraphy.) A plate buried in the earth, or a system of gas or water pipes utilized for the purpose, connected with the terminal or return wire at a station, so as to avail the earth itself as a part of the circuit, instead of using two wires, as was the practice previous to 1837.
Earth′quake-a-larm′.
An alarm founded on the discovery or supposition that a few seconds previous to an earthquake the magnet temporarily loses its power.
To an armature is attached a weight, so that upon the magnet becoming paralyzed the weight drops, and, striking a bell, gives the alarm.
Earth-ta′ble.
The lowest visible course of stone or bricks in a wall or building.
Earth′work.
An engineering term applied to cuttings and embankments.
Ear-trum′pet.
An instrument for the collection and conduction of sounds.
By increasing the size of the auricle, a larger volume of sound is gathered than by the natural ear.
The ear-trumpet for the assistance of the partially deaf is believed to have been invented by
Baptista Porta about 1600.
Kircher describes the funnel and tube for conveying sound, the device which is now so common for conveying intelligence between apartments and shops, in dwellings, warehouses, and factories.
Dr. Arnott of
England, who became partially deaf from a cold contracted in traveling, first devised the pair of shells or artificial ears which extend the surface displayed to gather the tremulous air.
There are two qualities required in a speakingtube: that it shall concentrate a large amount of sound in a small space; and, secondly, that it shall not stifle the sounds within the tube itself.
Guttapercha seems to answer the latter conditions better than any other material.
The ear-trumpets are of several descriptions: —
1. The
long ear-trumpet a, with a wide opening at the sound-reception end, and a small opening at
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the delivery end. This is made portable and compact by bending.
b has a rotatable section;
c is a shorter trumpet;
d d cane trumpets;
e a short one.
2. The ear-cornet
f is a small and neat affair, adapted to be worn on the head.
3. The
paraboloid trumpet, in which the sound is echoed from a large concave receiver before it enters the tube.
4. The auditorium trumpet, which is adapted to collect the sound of a speaker's voice and convey it to one or more parts of the room where the partially deaf persons may be sitting.
The uses of the acoustic tubes are various, forming means of communication between a captain and his engineer or steersman; a conductor and driver on a street-car; a conductor and engineer on a train; a messenger at the door and a doctor in his apartment; a housekeeper with the kitchen; an office with a factory; an editor with the compositor's room; a hospital office and the wards, etc.
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Ear-trumpets. |
In the auricle
f the tube of the ear-trumpet near where it enters the ear is intersected by a passage communicating with an artificial ear which is intended to lead such vibrations as fall on it to unite with the vibrations passing round through the tube.
A
sonifer is a bell-shaped instrument of metal placed on a table with the mouth turned in the direction whence the sound proceeds; the sound collected in the bottom of the instrument is conducted by a flexible tube to the ear of the person.
（
Microcoustic.) An instrument to assist the hearing.
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Easel. |
Eas′el.
A wooden frame for supporting a picture during its execution.
Eave.
The lower edge of a roof overhanging the wall.
Eave-board.
A feather-edge board, nailed above and across the lower ends of the rafters, to tilt up the lower edge of the lowest course of slates so that the next course may lie flatly upon them.
Eave-lead.
（
Building.) A leaden gutter inside a parapet.
Eave-mold′ings.
（
Architecture.) Those immediately below the eaves, as a cornice.
Eave-trough.
A trough, usually of tinned iron, suspended beneath an eave to catch the drip.
It is held by a strap or hanger, which may have means for the vertical adjustment of the trough, so as to give it the required fall in the length of the eave.
Eb′on-ite.
Mr. Goodyear's name for what is generally known as hard rubber.
It is a vulcanite with a larger proportion of sulphur and certain added ingredients.
The proportion of sulphur is from thirty
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to sixty per cent, and to this may be added certain amounts of shellac, gutta-percha, chalk, pipe-clay, sulphates of zinc, antimony, or copper.
It is used of many colors, as may be gathered from the above list of ingredients, and of hardness and consequent facility for taking polish.
The compound, mauger its name, may resemble horn, ivory, bone, wood, etc.
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Eave-trough hangers. |
E-bul′li-o-scope.
An instrument for determining the strength of a liquid by ascertaining its boiling-point.
Eccal-e-o′bi-on.
A chamber for hatching eggs by artificial heat.
See incubator.
Ec-cen′tric.
A disk or wheel
a fixed upon a shaft at some distance from its geometric-center.
Around it is placed a ring
d, within which it is at liberty to turn; the ring, however, does not turn, but rotates around the axis of
a, so as at its quarterly points to occupy the places indicated by the dotted circles, the effect of which is to rock the bellcrank lever
g g.
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Eccentries |
The upper portion of the figure shows a shiftable eccentric for varying the throw.
The
fore eccentric and
back eccentric impart forward and backward motions respectively to the valve-gear and the engine.
The eccentric is used in many other machines besides
steam-engines, to convert a rotary to a reciprocating motion.
Ec-cen′tric-catch.
See eccentric-hook.
Ec-cen′tric-chuck.
A chuck attached to the mandrel of a lathe, and having a sliding piece which carries the
center. This piece is adjustable in a plane at right angles to the axis of motion by means of a set screw, and carries the center to one side of the axis of motion.
By its means circular lines of varying size and eccentricity may be produced.
No oval or ellipse is produced thereby, but circles on the face of the work with their centers at such distance from the axis of the mandrel as may be desired.
Ec-cen′tric-cut′ter.
A cutting-tool placed upon the slide-rest, and having a rotation by means of a wheel and shaft, the cutter being attached to the end of the latter.
The rotation is obtained by an
overhead motion, and the eccentricity by fixing the cutter at different distances from the center by means of the groove and screw.
The action of the eccentric-cutter differs from that of the eccentric-chuck in this: in the latter the work is rotated and the tool is stationary; in the former the work is stationary and the tool revolves.
When the motions are used in conjunction, the patterns are capable of almost unlimited variation.
Ec-cen′tric-en-grav′ing.
An arrangement of diamond tracers, operated by elaborate machinery, acting upon a varnished roller designed for calicoprinting.
The effect is analogous to that produced by the rose-engine lathe.
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Eccentric-fan. |
Ec-cen′tric-fan.
A fan-wheel with radial arms and vanes, and having an axis which is eccentric with the case in which it revolves.
The case has a scroll form, and the effect is to make the discharge of air more perfect and avoid carrying a body of air around between the vanes.
Ec-cen′tricgab.
See eccentric-hook.
Ec-cen′tric-gear′ing.
Cog-wheels set on eccentric axes give a variable circular motion, as in the case of the eccentric
contrate wheel and pinion, and the eccentric spur-wheel and intermediate shifting pinion.
Links connect the axis of the pinion with those of the
driver and
driven wheels, and preserve the pinion at proper mashing distance, so as to engage with the
motor and communicate the motion to the next wheel in series.
Ec-cen′tric-hook.
（
Steam-engine.) One used to connect the eccentric-rod with the wrist on the lever of the rock-shaft which actuates the valve; otherwise called a
gab.
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Eccentric-gears. |
Ec-centric-hoop.
The strap on the eccentric of an engine.
Ec-cen′tric-pump.
A hollow cylinder in which is a revolving hub and axis eccentrically arranged.
On the hub are flaps which act as pistons in the space between the hub and the case to expel the water, which enters at one opening and departs by another.
The same construction is seen in rotary
steam-engines, only that in one case the shaft revolves to force water, and in the other the steam passes through to drive the shaft.
Ec-cen′tric-rod.
The rod connecting the eccentric strap to the lever which moves the slide-valve.
Ec-cen′tric-strap.
（
Machinery.) The ring inclosing an eccentric sheave and connecting by a rod to the object to be reciprocated; as, the slide-valve of a steam-engine.
See eccentric.
Ec-cen′tric-wheel.
A cam consisting of a circular disk attached eccentrically to a shaft.
It is used for communicating a reciprocating motion to the valve of a steam-engine.
Its axis of revolution is out of the center of its figure, and the rectilinear motion imparted is called the
throw.
The ring around the eccentric is the
eccentric-strap.
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The rod connecting the strap to the part to be actuated is the
eccentric-rod.
The hook at the end of the rod, by which it is connected to the rock-shaft of the valve motion, is the
eccentric hook or
gab.
The whole apparatus is the
eccentric-gear. See eccentric.
Ec-cope-us.
（
Surgical.) A surgeon's knife.
A
raspatory; an ancient instrument for trepanning.
E-chinus.
A member of the Doric capital; so called from its resemblance to the echinus, or large vase, in which drinking-cups were washed.
E-chom′e-ter.
（
Music.) A scale or rule marked with lines which serve to indicate the duration of sounds, and to ascertain their intervals and ratios.
E-clipse′--speed′er.
（
Cotton, etc.) A form of spinning-machine.
E′coute.
（
Fortification.) A gallery built in front of the glacis of a fortification, as a lodgment for troops to intercept the miners of an attacking force.
Ec-phora.
The projection of any member or molding before the face of the member or molding next below it.
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Ecraseur. |
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Edge-plane for shoe soles. |
E-cra′seur.
A steel chain tightened by a screw, and used for removing piles, polypi, malignant growths, etc. Used also in obstetrical practice.
Ec-ty-pog′ra-phy.
A mode of etching which gives the design in relief.
The plate is exposed by the etching-needle between the lines, instead of at the lines.
Edge-cut′ting.
The process of giving a smooth edge to books by cutting off the folds and making the margins of all the pages equal.
The book is held in a
cutting-press and the work done by a
plow or
trimming-machine.
Edge-joint.
（
Carpentry.) A joint formed by two edges, forming a corner.
Edge-mill.
An ore-grinding or oil-mill in which the stones travel on their edges.
In addition to the crushing action, the
edge-mill has a frictional or grinding action, whose relative value may be considered as equal to the difference of distance performed by the inner and outer edges.
See Chilian-mill.
Edgeplane.
1. (
Wood-working.) A plane for edging boards, having a fence, and a face with the required shape; flat, hollow, or round.
2. (
Shoemaking.) A plane for shaving the edges of boot and shoe soles.
It has a knife curved to the shape desired, a projecting edge which forms a guide and gage, and means for adjustment.
The mouthpiece is adjustable, and holds the curved paringknife by means of its jaws and set-screw.
Edg′er.
A circular saw or pair of circular saws by which the bark and “
waney” portions are ripped from slab-boards or boards made by ripping logs through and through, without squaring.
A double-edger has one permanent saw and one capable of regulation as to distance from the former one, so as to adapt the pair of saws to edge boards of varying width.
Edge-rail.
（
Railroad.)
a. One form of railroad-rail, which bears the rolling stock on its edge.
The rail is contradistinguished by its name from the
flat-rail, which was first used; the
angle-rail, which succeeded that; the
bridge-rail, which presents an arched tread and has lateral flanged feet; the
footrail, which has a tread like the
edg-rail, but, unlike it, has a broad base formed by foot flanges.
The first public railway laid with edge rails was made by
Jessop of
Loughborough, England, 1789.
They were of cast-iron in 3 or 4 feet lengths, and had vertical holes near each end by which they were wooden-pinned to the sleepers.
They were fishbellied, and subsequently laid on cast-iron chairs.
Wyatt's patent in 1800 was an oval east-iron rail.
The upper surface was afterwards flattened.
Rolled-iron
edge-rails were made in 1820 under Birkenshaw's patent.
See rail; Railway.
b. A rail placed by the side of the main rail at a switch to prevent the train from running off the track when the direction is changed.
Edge-roll.
（
Bookbinding.) A brass wheel, used hot, in running an edge ornament on a book cover, either gold or blind.
Edge-shot.
A board with its edge planed is said to be
edge-shot.
Edge-tool.
（
Hardware.) A general name which includes the heavier descriptions of cutting-tools,— axes, adzes, chisels, gouges, plane-bits.
Other cutting-tools come within the province of the another or cutler, and are included under
cutlery, — knives, scissors, shears,
surgical instruments, and, by the analogy of associated use, forks.
See adze; axe; hatchet; knife.
The making of swords was anciently the work of the armorer, but has probably merged into
cutlery.
Wood-cutting tools are divided by
Holtzapffel as follows:—
1.
Paring or
splitting tools, with thin edges, the angle of the basil not exceeding 60° with the straight face.
This includes
broad-axes, chisels, gouges, etc.
Double-basil tools, such as
axes.
2.
Scraping-tools with thick edges, the angles measuring from 60° to 120°. These remove the fibers in the form of dust.
The
vencer-scraper is an instance.
One angle of the edge of the steel plate is turned over to form a
bur, known as a
wire-edge.
3.
Shearing-tools; such are usually in pairs, acting from opposite sides of the object, the basil and face having an angle of from 60° to 90°.
Iron and steel for edge-tools have been combined in a fagot and rolled so as to have a thickness of steel between layers of iron, for chopping-axes and some other tools, and with a layer of steel on one side for broadaxes, chisels, etc., which have but one basil.(Bouydell's patent,
English.)
4. A burnisher for rubbing the edges of boot and shoe soles.
See also edge-plane.
5. (
Saddlery.) A tool used for removing the angular edge from a leathern strap.
For chamfering down the edges of a strap more broadly, another tool is used having a blade and
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guides which travel along the edge and face respectively of the leather.
See chamfering-tool.
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Edge-tool. |
Edge-wheel.
A wheel traveling on its edge in a circular or annular bed, as in the ancient Phoenician oil-mills, the Chilian ore-mills, and many other crushing-mills.
See Chilian mill.
Edging.
The ornamentation of book edges by—
1. Color sprinkling.
2. marbling (which see).
3. Gilding.
4. Coloring; as the rubric style now so common.
Edg′ing-ma-chine′.
A machine for edging boards to a given pattern.
An
edger.
Edg′ing-shears.
A gardener's shears for trimming the edges of sod around walks or beds.
Edg′ing-tile.
Tiles for borders of garden-beds, in place of grown edgings, such as box, shrift, etc. Such tiles for pleasure-gardens are made ornamental; for kitchengardens, plainer.
E-duc′tion-pipe.
（
Steam-engine.) The pipe which carries off the exhaust steam from the cylinder.
E-duc′tion-port.
One through which the steam passes from the valves to the condenser.
Exhaustport.
E-dulco-ra′tion.
The effusion of water on any substance for the purpose of removing the portion soluble in that liquid.
The article is usually agitated in water, which is removed by decantation after subsidence of the heavier portion.
E-dulco-ra′tor.
A dropping-tube for applying small quantities of sweet solutions to a mixture.
Ef-fect′.
The amount of work performed by a steam-engine or other machine.
See duty.
Egg-as-sort′er.
A device by which eggs are assorted according to quality; being so placed that a strong light is brought upon them when stuck into holes in a board, their comparative translucency is observed, and is accepted as an evidence of quality.
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Egg-basket. |
Egg-bas′ket.
One for standing eggs in to boil, and also to hold them when placed on the table.
Egg-beat′er.
A whip of wires or a set of wire loops rotated by gear while plunged in the egg contained in a bowl.
Another form is a vessel contained in another, and a wire gauze diaphragm through which the eggs pass when the vessels are reciprocated.
Egg-boil′er.
A domestic device which sounds an alarm when the eggs have been exposed to the water a sufficient length of time to expand the water in the lower reservoir, raise the plug
d, and release the trigger of the spring bell-hammer.
Egg-car′ri-er.
A means for holding eggs in the proper carrying position without jolting against each other during transportation.
The frames have cloth pockets for the eggs.
In other forms the eggs are supported by pockets of wire or netting.
Egg-de-tect′or.
An apparatus for showing the quality of eggs.
They are placed upright in the holes in the lid of the dark chamber, and their transmitted light observed upon a mirror
C; being viewed through a peep-hole, their quality is determined by their translucency as evinced by the relative transmission of light, as an egg becomes more cloudy and opaque as it becomes spoiled.
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Egg-beaters. |
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Egg-boiler. |
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Egg-carrier. |
Egg-glass.
1. A glass for holding an egg while eating it.
2. A sand-glass running about three minutes, as a timist for egg-boiling.
Egg-hatch′ing Appa-ratus.
An apparatus for the artificial hatching of eggs.
It has been practiced from time immemorial in
Egypt.
See incubator; Calorifere.
Egg-mold′ing; egg and tongue.
（
Architecture.) A peculiar molding in which a tongue de-
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pendent from the corona alternates with an oval boss whose major diameter is vertical, like an egg set on end.
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Egg-detector. |
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Egg-tongs. |
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Eidograph |
Egg-tongs.
A grasping implement for seizing and holding an egg.
Ei′do-graph.
An instrument for copying drawing, invented by
Professor Wallace.
It consists of a central beam of mahogany, sliding backward and forward in a socket whose axis passes through a longitudinal slit in the beam.
Two equal wheels, one below each end of the beam, turn on axes that pass through pipes fixed at
a b, near its extremities, and a steel chain passes over the wheels as a band by which motion may be communicated from one to the other.
Two arms
f f slide in sockets along the lower face of the wheels, just under their centers, one of which bears at its extremity
h a metallic tracer, having a handle by which its point may be carried over the lines of any design, while at the extremity
g of the other arm is a pencil, fixed in a metallic tube which slides in a pipe and is raised by a string, when required, the pressure on the paper being maintained by a weight.
The wheels being exactly equal in diameter, the arms attached to them, when once set parallel to each other, will remain so when the wheels are revolved.
For use, the instrument is set by sliding the central beam, so that the distance
b c shall bear the same proportion to
a c as the drawing to be copied is intended to bear to the copy.
The distances
b g, a h, are also regulated to the same proportion.
The center-piece and arms are graduated for this purpose, so as to admit of being set to any desired ratio.
Eido-scope.
An instrument on the principle of the kaleidoscope, which produces an infinite variety of geometrical figures by the independent revolution of two perforated metallic disks on their axes.
It may be employed in conjunction with the magic-lantern, when rapidly rotated causing flashing rays of light, forming singular combinations to appear upon the screen.
Variously colored glass disks may be used, producing striking variations and combinations of color. —
Mechanical Magazine,
N. S., Vol.
XVII. p. 35.
Eight-een′--mo.
A book whose sheets are folded to form eighteen leaves.
Sometimes written
octodecimo; and usually indicated 18mo, or 18°.
Eight-line Pica.
（
Printing.) A type whose face has eight times the depth of pica.
French,
doublecanon.
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Pease's oil-well ejector. |
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Ejector. |
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Ejector. |
E-ject′or.
1. A device wherein a body of elastic fluid, such as steam or air, under pressure and in motion is made the means of driving a liquid such as water or oil. The effect of a body of escaping steam in setting liquids in motion was observed longsince, but the most notable instance is the
Giffard Injector (see injector), which is used as a feed-water pump for steam-boilers.
The
ejector acts on a similar principle, but is applied to
eject or lift liquids, as in the example (
Fig. 1833), where it is an oil-well pump.
B is a pipe which proceeds from the surface of the ground to near the bottom of the well; its lower end is closed by a valve which opens upward.
A steam-pipe passing down alongside the main pipe is recurved upwardly, and emits steam just in the throat of the contracted aperture.
The effect is to draw up liquid by the force of the steam-
[
776]
blast and carry it through the aperture, and so upwardly to the top. See also
Figs. 59 to
64, inclusive.
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|
Ashes-ejector. |
Fig. 1834 is upon the same principle, the steam or air issuing through the small axial-pipe and passing into the up-cast pipe, drawing with it the liquid from the lower pipes which surround the ejector-nozzle.
Fig. 1835 only differs in the mode of application, the bent pipe having an unobstructed passage in the nozzle for the admission of steam or air, communicating with the said passage on its back or outer curved side at a point directly opposite to and in line with the outlet or discharge opening.
2. That device in a breech-loading fire-arm which withdraws the empty cartridge-case from the bore of the gun.
3. A device on shipboard (
Fig. 1836) for carrying up the ashes from the stoke-holes of steamships and discharging them overboard.
The ashes are shoveled into a box, and a steam-jet being driven into the mouth-piece of the pipe causes an induced current of air which carries the ashes along with it, up the pipe, and overboard above the water-line.
E-ject′or-con-dens′er.
（
Steam-engine.) A form of condenser worked by the exhaust steam from the cylinder.
In the example it is shown as applied to a pair of engines.
The apparatus consists essentially of three concentric tubes terminating in conoidal nozzles, and opening into the hot-well or waste-water receptacle by a common and gradually widening or trumpet-shaped mouth-piece
D; the inlet-tube
B is in communication with the watertank from which the current of injection-water is obtained, while each of the other tubes
C conveys the exhaust steam from one of the cylinders.
A is a regulating-spindle for adjusting the watersupply;
B, the water-inlet;
C C, the exhaust passages;
D, the discharge passage;
E, the steaminlet;
F, a self-adjusting steam-valve.
In starting, steam is admitted at
E, and passing along the axialpipe, issues at the nozzle, drawing with it water from cold-water pipe
B, which condenses the steam from the exhaust passages
C C of the respective cylinders, and has momentum enough to carry the condensed steam and itself to the hot-well.
Eke′ing.
（
Shipbuilding.)
a. A piece fitted to make good a deficiency in length on the lower part of the supporter under the cat-head, etc.
b. The piece of carved work under the lower end of the quarter-piece at the aft part of the quartergallery.
E′lai-om′e-ter.
An instrument for detecting the adulteration of
olive-oil.
E-las′tic-bulb Syr′inge.
A syringe having a bulb of caoutchouc, whose expansion and contraction acts as a pump.
See breast-pump ; atomizer.
E-las′tic bands.
Made of caoutchouc, naked or covered.
The former are cut from flattened cylinders of rubber of proper diameter and thickness between a duplicate series of circular knives acting after the manner of shears; the latter are made by cutting continuous slips from a sheet of vulcanized rubber of the required thickness, wound upon a reel, by means of a knife with slide-rest motion.
These strips are then covered with cotton or silk, and woven in an endless web. See caoutchouc.
E-las′tic-fab′ric loom.
One having mechanical devices for stretching the rubber threads or
shirrs, and holding them at a positive tension while the fabric is woven.
E-las′tic goods.
Those having elastic cords, called
shirrs, inserted in a fabric or between two thicknesses.
E-las′tic mold.
Elastic molds of glue for taking casts of
undercut objects were invented by
Douglas Fox,
Derby, England.
The body to be molded is oiled and secured about an inch above the surface of a board, and is then surrounded by a wall of clay rather higher than itself, and about an inch distant from its periphery.
Into this, warm melted glue, just fluid enough to run, is poured, completely enveloping the object.
When cold, the clay wall is removed, and the mold delivered by cutting it into as many pieces as are required, either with a sharp knife or by threads previously placed in proper situations about the object.
The pieces are then placed in their proper positions, and bound together.
The mold is designed particularly for taking casts in plaster-of-paris, but molten wax, if not too hot, may also be employed.
E-las′tic Pis′ton-pump.
A pump described in
Dr. Gregory's “Mechanics” consists of an elastic bag provided with a valved board on top, and operating over a valved diaphragm.
The trunk in which it operates is a square box, and the piston moves without friction against the trunk in which it works.
The bag is of water-proof canvas or leather, with occasional rings.
A somewhat similar pump, recommended for a bilge-water pump, and for pumping out leak-water, is known as Cracknell's, and was somewhat famous in
England forty years since.
It had a pliable diaphragm of leather attached to the plunger-rod, and a valve on top like the pump just described.
As the leather diaphragm was driven down and drawn up alternately, it filled with water and then lifted it, the lower valve rising as the plunger lifted.
See Bagpump.
E-las′tic pro-pel′ler.
A form of ship's propeller invented by
Macintosh, in which the blades are of flexible steel, which assume a more and more nearly disk form as the speed and consequent resistance of the water is increased.
E-las′tic type.
Type made of compounds of caoutchouc, which will accommodate themselves to a somewhat uneven surface in printing, and in which a form of said type may be lapped around a curved printing-surface.
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E-lat′er-om′e-ter.
A pressure-gage for air or steam.
El′bow.
1. The junction of two parts having a bent joint.
A
knee or
toggle joint.
An abrupt angle.
2. A bend, as of a stove-pipe, a wall, a parapet.
3. A support for the arm, elbow high, as the arm of a chair.
4. A voussoir of an arch which also forms part of a horizontal course.
An obtuse angle of a wall.
5. (
Joinery.) The sides or flanks of a paneled recess; especially) the two small pieces of framing which occur on each side of a window immediately below the shutters when the window-jambs are carried down to the floor, forming a slight recess.
El′bow-board.
（
Carpentry.) The board at the bottom of a window on which the elbows of a person are supported when leaning.
Elbow-tongs.
A crucible tongs with jaws bent between the joint and chaps.
Elec-trep′e-ter.
An instrument for changing the direction of electric currents.
E-lectri-cal Appa-ra′tus.
Gilbert, in his book “De Magnete,” 1600, first introduces into the nomenclature of the sciences the word “electric,” deriving it from
electron (Gr.
amber), which was the only substance known to the ancients that acquired the property of attracting light bodies when rubbed.
He gives a list of bodies, as diamond, sapphire, crystal, glass, sulphur, sealing-wax, and others, possessing the electric property, which he very properly distinguishes from magnetic power, the former attracting all light bodies, the latter iron only.
He regarded magnetism and electricity as two emanations of one fundamental force.
He considered the earth as a magnet, and the lines of equal declination and inclination as having their inflections determined by distribution of mass, or by the forms of continents and by the extent of the deep intervening occanic basins.
Gilbert was surgeon to Queen Elizabeth and James I., and died in 1603.
The electric-telegraph preceded the electro-magnetic by many years.
See electric-telegraph.
Otto Guericke, of
Magdeburg, discovered that there was a repulsive as well as an attractive force in electricity, observing that a globe of sulphur, after attracting a feather to it, repelled it until the feather had again been placed in contact with some other substance.
Newton, in 1675, observed signs of electrical excitement in a rubbed plate of glass.
Hawkesbee, who wrote in 1709, also observed similar phenomena; and Dulay in the “Memoirs of the French Academy,” between 1733 and 1737, generalized so far as to lay down the principle that electric bodies attract all those which are not so, and repel them as soon as they have become electric by the vicinity or contact of the electric body.
Dufay also discovered that a body electrified by contact with a resinous substance repelled another electrified in a similar way, and attracted one which had been electrified by contact with glass.
He thence concluded that the electricity derived from those two sources was of different kinds, and applied the names vitreous and resinous to them.
Franklin attributed this difference to an excess or deficiency of the electric fluid, the former condition existing in electrified glass and the latter in resins.
Otto Guericke had observed that his sulphur globe, when rubbed in a dark place, emitted faint flashes of light, and shortly afterward it was noticed that a similar phenomenon occurred at the surface of the mercury when the barometer was shaken; a fact which one of the celebrated mathematicians, Bernoulli, attempted to explain on the Cartesian system, but which was afterwards correctly attributed by Hawkesbee to electricity.
Wall, in 1708, observed the sparks produced from amber, and Hawkesbee noticed the sparks and “snapping” under various modifications.
Dufay and the
Abbe Nollet were the first to draw sparks from the human body; an experiment which attracted great attention, and became a species of fashionable diversion at the time.
The discovery of the Leyden jar is attributed to Cunoeus of
Leyden, in 1746, who, while handling a vessel containing water in communication with an electrical machine, was surprised at receiving a severe shock; a similar event had happened the year previous to
Von Kleinst, a German prelate.
Gray in 1729 discovered that certain substances were possessed of a conductive in contradistinction to an electric power; and afterwards Nollet passed a shock through a circle of 180 men of the
French guards, and along a line of men and wires 900 toises in length, while
Watson in
England ascertained that the transmission of the shock through 12,000 feet of wire was sensibly instantaneous.
Franklin in 1747 pointed out the circumstances on which the action of the Leyden jar depends, showing that the inside is positively and the outside negatively electrified, and that the shock is produced by the restoration of the equilibrium when communication is established between them.
Monnier the younger discovered that the electricity which bodies can receive depends on their surface rather than their mass, and
Franklin soon found that “the whole force of the bottle and power of giving a shock is in the glass itself” ; he farther, in 1750, suggested that electricity and lightning were identical in their nature, and in 1752 demonstrated this fact by means of his kite and key; about the same time D'Alibard and others in
France erected a pointed rod forty feet high at Marli, for the purpose of verifying
Franklin's theory, which was found to give sparks on the passage of a thunder-cloud.
Similar experiments were repeated throughout
Europe, and in 1753
Richman was instantly killed at
St. Petersburg by a discharge from a rod of this kind.
The more important discoveries since those days relate rather to electricity produced by voltaic or magnetic action.
See, under the following heads: —
E-lec′tri-cal and Mag-net′i-cal Ap-pli′--an-ces.
| Annunciator. | Doubler. |
| Anode. | Dry-pile. |
| Armature. | Earth-battery. |
| Astatic needle. | Earth-plate. |
| Battery. | Electrepeter. |
| Calorimotor. | Electrical apparatus. |
| Carbon-battery. | Electric alarm. |
| Catelectrode. | Electrical machine. |
| Cathode. | Electric annunciator. |
| Cell. | Electric balance. |
| Circuit. | Electric battery. |
| Circuit-breaker. | Electric bridge. |
| Circuit-closer. | Electric cable. |
| Commutator. | Electric clock. |
| Compound battery. | Electric escapement. |
| Condenser.
Electric | Electric fuse. |
| Conductor. | Electric governor. |
| Constant battery. | Electric harpoon. |
| Couple. | Electric heater. |
| Current-regulator. | Electric helix. |
| De Luc's column. | Electric indicator. |
| Dip. | Electric lamp. |
| Dipping-needle. | Electric light. |
| Discharging-rod. | Electric log. |
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778]
| Electric loom. | Lightning-arrester. |
| Electric meter. | Lightning-conductor. |
| Electric pendulum. | Lightning-rod. |
| Electric piano. | Line-wire. |
| Electric railway-signal. | Magnet. |
| Electric regulator. | Magnetic battery. |
| Electric signal. | Magnetic compensator. |
| Electric steam-gage. | Magnetic curative-appliances. |
| Electric switch. |
| Electric telegraph. | Magnetic guard. |
| Electric time-ball. | Magnetic hone. |
| Electric torch. | Magnetic needle. |
| Electric wand. | Magneto-electric apparatus. |
| Electric weighing-apparatus. | Magneto-electric machine. |
| Electric whaling-apparatus. | Magneto-electric telegraph. |
| Electro-ballistic apparatus. | Magnetograph. |
| Magnetometer. |
| Electro-blasting. | Manipulator. |
| Electro-chemical telegraph. | Mariner's compass. |
| Meteorometer. |
| Electro-chronograph. | Multiplier. |
| Electrode. | Negative. |
| Electro-dynamic engine. | Organ.
Electric. |
| Electro-engraving. | Pantelegraph. |
| Electro-etching. | Paragrandine. |
| Electro-gilding. | Paragrele. |
| Electrolyte. | Pendulum.
Electric |
| Electro-magnet. | Pile. |
| Electro-magnetic clock. | Polarized armature. |
| Electro-magnetic engine. | Pole. |
| Electro-magnetic machine. | Positive. |
| Electro-magnetic regulator. | Prime-conductor. |
| Receiving-magnet. |
| Electro-magnetic telegraph. | Reel-telegraph. |
| Relay-magnet. |
| Electro-magnetic watch-clock. | Repeater. |
| Resistance-box. |
| Electro-medical battery. | Resistance-coil. |
| Electrometer. | Rheometer. |
| Electro-motor. | Rheomotor. |
| Electro-negative. | Rheophone. |
| Electronome. | Rheoscope. |
| Electrophorus. | Rheostat. |
| Electro-plating. | Rheotome. |
| Electro-positive. | Rheotrope. |
| Electro-puncturing. | Rubber. |
| Electroscope. | Ruhmkorff battery. |
| Electrotint. | Sideroscope. |
| Electrotype. | Signal-box. |
| Filings-separator. | Sounder. |
| Galvanic battery. | Submarine-cable. |
| Galvanizing-iron. | Switch. |
| Galvanography. | Telegraph (varieties, see telegraph.） |
| Galvanometer. |
| Galvanometric multiplier. | Telegraph-cable. |
| Galvanoplastic process. | Telegraph-clock. |
| Galvanoscope. | Telegraphic signal. |
| Geisler-tube. | Telegraph-indicator. |
| Hydro-electric machine. | Telegraph-instrument. |
| Inclinatorium. | Telegraph-key. |
| Inclinometer. | Telegraph-wire. |
| Induction apparatus. | Terminal. |
| Induction coil. | Thermo-electric pile. |
| Inductometer. | Torsion-balance. |
| Insulated wire. | Torsion-electrometer. |
| Insulating-stool. | Trough. |
| Insulator. | Unit-jar. |
| Inversor. | Variation-compass. |
| Leyden battery. | Volta-electrometer. |
| Leyden jar. | Voltaic battery. |
| Lighting gas by electricity. | Voltaic light. |
| Voltaic pile. |
| Voltameter. | Voltatype. |
| Voltaplast. | Zambonis-pile. |
E-lec′tric A-larm′.
An instrument, otherwise known as a
thermostat, used for giving an alarm when the temperature rises to a point at which the instrument completes the circuit.
This is used in stoves and hot-houses, to indicate excess or lack of temperature, and as a maximum thermometer-alarum or tire-alarm, which is made by carrying one platinum wire in connection with a battery and bell into the bulb of a mercurial thermometer, and another wire down the tube to the degree it is not desired to exceed.
When the mercury rises to this point, the circuit is completed, and notice is given by the ringing of the bell.
One form of the minimum temperature alarm consists of a spirit-thermometer, the bulb of which is placed above and the tube curved in a
U-shape.
A platinum wire is carried into the bulb and down to the degree of heat it is wished to notify.
Below this minimum the curvature is filled with mercury, which is in free communication with a second platinum wire.
As the alcohol contracts with the cold, the mercury will, of course, rise, and, reaching the first platinum wire, complete the circuit and give the warning.
One bell and the same battery will serve for the two thermometers; but it will be necessary to interpose a commutator to ascertain through which circuit the current is passing, and whether a rise or fall is indicated when the bell is rung.
Fire-alarms constructed on the same principle are placed in different apartments of a building, the increased temperature in that where fire happens to first break out expands a wire or column of mercury, which, by completing a circuit, sounds an alarm.
The most compact form of the thermostat is that resembling the chronometer-balance.
See thermostat ; fire-alarm.
E-lec′tri-cal ma-chine′.
An apparatus for generating, or rather collecting or exciting, electricity by means of friction.
The
Greeks were aware that amber, when rubbed, acquired the power of attracting and repelling light bodies; and for many ages this property was supposed to be peculiar to amber, from the Greek name of which (
η>´λεκτρον) the word “electricity” was derived.
It was subsequently discovered that the same effect was produced by resinous substances rubbed with flannel, and by glass when rubbed with silk; and our readers may have noticed that by stroking a cat's back smartly with the hand in clear frosty weather, a crackling noise accompanied by a tingling sensation is produced.
Substances in the condition referred to are said to be electrically excited.
This excitement is termed positive if glass be the material employed, and negative if resin be used; the kind of electricity developed by each substance having a tendency to attract that derived from the other, and to repel that of the same kind as itself.
According to the theory of Dufay, the two kinds were called vitreous and resinous; the former being derived from glass and corresponding to the positive of
Franklin, and the latter from resin, corresponding to the negative.
It is by the latter terms, positive or +, and negative or —, that the two kinds are now universally known.
See
supra, page 777.
In machines for developing frictional electricity in quantities, glass is the material employed, either in the form of a hollow cylinder rounded at the ends or of a circular plate.
These are rotated in contact with a leather-covered cushion, upon the surface of which a thin layer of an amalgam composed of tin,
[
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zinc, and mercury is spread, and a suspended flap or apron of silk.
Gilbert, in 1600, conjectured the fundamental identity of the forces known as magnetism and electricity, and measured the strength of the electricity excited by rubbing amber, glass, resin, etc. His electrometer was an iron needle poised on a pivot.
Otto Guericke, of
Magdeburg, recognized phenomena of repulsion.
“He heard the first sound and saw the first light in artificially excited electricity.”
Newton saw the first traces of an “electric charge” in 1675, in some experiment with a rubbed plate of glass.
Although Wall in 1708,
Gray in 1734, and Nollet, conjectured the identity of frictional electricity and lightning, yet
Franklin was the first to attain the experimental certainty by his well-known kite experiment in 1752.
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Electrical machine. |
Electrical machines were formerly made cylindrical, but are now more frequently made with a circular glass disk rotated by a hand-crank.
The glass passes between rubbing surfaces, and the electric current which is generated passes to the conductors on each edge of the disk, and thence to the prime conductor, when it passes to a Leyden jar or other object, as may be desired.
The plate-machine of the University of Mississippi has two plates each 6 feet in diameter.
One made for the
London Polytechnic Institute has a plate 10 feet in diameter driven by a steam-engine of 4-horse power.
See Desenanel's “Natural philosophy,” Part III. pp. 533-545.
E-lec′tric an-nun′ci-ator.
A form of annunciator in which a circuit wire is the means of shifting the shield covering the number aperture on the dial, or performing other duty to expose the number of the room.
The guest in his room touches a stud upon the wall; the circuit being made or broken, the effect is evidenced by the exposure of the room number in the hotel-office.
It is an electromagnetic expedient as a substitute for a pulling wise.
See annunciator.
E-lec′tric Bal′ance.
An instrument for measuring the attractive or repulsive forces of electrified bodies.
A form of electrometer.
It consists of a graduated are
a b supported by a projecting plate of brass which is attached to the perpendicular column.
A wheel
d, the axis of which is supported on anti-friction rollers
f f, and is concentric with that of the graduated are
a b, carries an index
c.
Over this wheel, in a groove on its circumference, passes a line, to one end of which is attached a light ball of gilt wood
g, and to the other a float
i l, which consists of a glass tube about two tenths of an inch in diameter, terminating in a small bulb
l at its lower end, which contains a small portion of mercury or some very fine shot, put into it for the purpose of adjusting the instrument, so that the index
c may point to the zero division or center of the graduated are. The difference between the weights of the float when in and out of water is known, and the diameter of the wheel carrying the index is such that a certain amount of rise or fall of the float causes the index to move over a certain number of graduations on the are. The body whose electricity is to be measured is presented at
b, and its attractive or repulsive power on the ball
g is estimated by the rising or falling of the float in the fluid, and consequent motion of the index
c, as shown by the graduated are.
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Electric-balance. |
When the attractive force of the two bodies is to be estimated, the line passing over the wheel
d must be formed of two parts, the lower part being of silver thread and the remainder of silk; when their repulsive force is to be estimated, the whole is of silk.
See electrometer ; galvanometer.
E-lec′tric Bat′ter-y.
A series of
Leyden jars having all their interior and exterior coated surfaces connected with each other by means of conductors, so that the accumulated electricity of the whole may be made to act together, resembling the effects of lightning itself.
A large battery of this kind is capable of polarizing bars of iron or steel, and instantaneously melting iron or tin wire into globules, which are dispersed in all directions, the fusion of the latter metal being accompanied by a cloud of blue smoke, a dazzling flash, and a loud report.
Small animals are killed by it, and a violent shock given to the human system.
See Leyden-jar.
E-lec′tric bridge.
（
Electricity.) A term applied to an arrangement of electrical circuits used for measuring the resistance of an element of the circuit.
The most generally known and used are the Wheatstone “bridge” or “balance,” and that of the British Association.
The former in substantial respects is adopted in the
Siemen's universal galvanometer, in such general use.
 |
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Electric-bridge. |
The principle involved is that an electrical circuit being divided into two branchcircuits, and again united, and the branches “bridged” or connected by a “short cut,” if the resistances in the branches on one side of the “bridge” are in the same ratio to each other as the resistances on the other side, no current will traverse the “bridge” ; if the ratios are not equal, a current will traverse the bridge.
A A, metallic circuit from battery
B divided into branches 1, 2, and 3, 4, which again unite.
Calling resistance “R,” when R 1: R 3 : : R 2 : R 4,
[
780]
an equilibrium or “balance” is established, and there is no appreciable current in the “bridge”
a b, in which is inserted the galvanometer
G.
In use, the resistance of one of the members, say 4, being known, the unknown resistance is inserted in 2 and its resistance calculated from the deflections of the needle in the galvanometer, caused by the current thrown through the “bridge.”
See Duplextelegraph.
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|
Electric cable. |
E-lec′tric Ca′ble.
Various forms of telegraph cable for submarine uses have been proposed.
That between
England and
Ireland is composed of a single copper wire covered with gutta-percha, surrounded by hempen yarn, and the whole protected by ten No. 8 iron wires twisted.
That between
Dover and
Calais has four copper wires covered with gutta-percha twisted into a rope, and protected in similar manner.
It weighs seven, and the Irish two, tons to the mile.
The first Atlantic cable was composed of seven No. 22 copper wires, covered with gutta-percha, hempen yarn, and an outside coating of iron wire.
This weighed 19 cwt. to the mile.
The cut shows a cable with coils diversely twisted.
See telegraph cable.
E-lec′tric clock.
A dial with hands and goingtrain impelled by recurrent impulses from an electromagnet.
The first known clock of this kind was invented by
Wheatstone and exhibited by him in 1840.
Appold,
Bain,
Shepherd, and others have contrived clocks on the same principle.
See electro-magnetic clock.
E-lec′tric es-cape′ment.
A device actuated by electric impulse which intermittingly arrests the motion of the scape-wheel and restrains the train to a pulsative motion, — acting, in fact, in the place of a pendulum.
An electric pendulum at a central station may be the regulator of numerous distant clocks with electric escapements, with each of which it is connected by circuit or circuits.
In some cases the device has alternately a detent and impulse action, and is the motor as well as regulator.
Devices in which a train is set in motion, or a machine started or stopped, are not strictly escapements, but may be considered as
electrical-governors or
electrical-regulators.
In that illustrated, the lever
L and its corresponding one on the opposite side, not shown, are caused to vibrate to the action of the circuit; these cause the anchorshaped piece
L′ T T to strike alternately against each of the pallets
P P′, which are fastened by springs, and yield in either direction, so as to alternately retain and release the scapewheel
W.
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|
Electric escapement. |
E-lec′tric fuse.
A device used in blasting to explode the charge.
The fulminate or the charge itself is lighted by means of an electric spark or a resistance section of fine platinum wire, which is heated to redness by the passage of an electric current induced by a voltaic or magneto-electric battery.
See fuse.
E-lec′tric Gov′ern-or.
One in which a part of a fly-wheel, say a segment of the rim, is made to move radially outward when the wheel revolves at a rate above a preappointed speed, and thereby comes in contact with a metallic tongue completing an electric connection, which is utilized to move a butterfly-valve or other device which concerns the transmission of power.
Governor-balls flying out to a certain distance may make or break an electric connection to produce the same result, or sound an alarm.
Electro-magnetic action is also used to start and stop machines, and operate stop-motions.
E-lec′tric har-poon′.
An application of the electric force to the explosion of a bursting-charge in a harpoon or bomb-lance.
A copper wire is carried through the line, and, when a circuit is established by the harpooner, a resistance-section in the fuse of the bomb-lance ignites the charge.
See harpoon ; bomb-lance.
E-lec′tric Heat′er.
A device in which a fine platinum wire heated by a passing electric current is made to communicate sensible heat as a means of warming or burning, as the case may be. It has been used as a local cautery, has been suggested for amputating, and for some other purpose, which it would excite a smile to name.
It is a lower application of the same principle as is developed in the electric light; a body of relatively great resistance is included in a circuit, and, failing to carry the electricity, a part of the latter takes the form of heat.
E-lec′tric He′LIX.
A coil of copper wire around a bar of soft iron; the coil forms part of an electric circuit, and confers polarity upon the iron.
The two constitute an electro-magnet.
 |
|
Electric indicator. |
E-lec′tric In′di-cator.
The apparatus shown in
Fig. 1843 is for indicating electro-magnetic currents, and consists of a wheel having figures upon its periphery turned by a star-wheel
E2 upon its shaft The star-wheel is actuated by pawls
J J K K, connected with armature levers
G G2 turning one cog, equal to one figure, at each completion of the circuit through one of the spool-magnets
P P. The two magnets are arranged to cause opposite rotation, and either may be connected with the operating-key by a switch.
The circuit passes through the axis of the key and through numbered buttons upon a disk.
The key being brought in contact with a button causes one movement of the numbered wheel, and each time the key comes in contact with a button the wheel is moved one figure, and no more.
E-lec′tric lamp.
A box or case provided with an electric lighting-apparatus.
See electric light.
E-lectric light.
An intense light generated by
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781]
passing an electric current between two pieces of charcoal fixed at the positive and negative ends of the circuit.
The electricity developed may be either derived from voltaic action or from magnets in connection with a series of helixes arranged on a rotating wheel, the latter source being preferred for practical application to illuminating purposes.
The lights of the natural lanterns carried by fireflies, glow-worms, and some species of nocturnal moths, may be considered as
electric lights.
Though classed as phosphorescent, some of them are intermittent, and we suppose the nervous action by which they are flashed into brilliancy to be in the nature of what we call a voltaic impulse from the battery. — the brain.
The electric light was first brought into notice in 1846.
The patent of
Greener and
Staite of that year embraced an arrangement whereby small lumps of pure carbon, inclosed in air-tight vessels, were rendered luminous by currents of galvanic electricity.
Two small cylinders or bits of pure carbon were placed nearly in contact with their points toward each other, and maintained at a constantly equal distance apart by means of clockwork, which slowly advanced them as they were consumed by combustion.
Through these the current of a galvanic battery was transmitted, so that the circuit would not be complete without traversing the small space between the points of the two pieces of carbon; this generated an intense heat at this spot, causing the combustion of the carbon, which was accompanied by an extremely brilliant light.
The chief practical difficulty was found to be in maintaining the points at such a distance from each other as to render the light continuous instead of intermittent.
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Electric light. |
This is now effected by means of an electro-magnet and a clock movement, the duty of the latter being to bring the two points together as they are gradually worn away by the passage of the electric current, while the former checks the clock action when not required.
The positive carbon pencil is found to wear much more rapidly than the negative; and in order to maintain the point where the light is produced at a uniform elevation, the cord by which each point is advanced is caused to pass around a barrel, larger for the positive and smaller for the negative, so as to take up unequal quantities of cord.
When the battery employed is very powerful, the electricity between the points assumes the form of an are of dazzling brilliancy.
With 600
Bunsen's cells arranged consecutively, an are 7.8 inches in length was obtained; and when the 600 cells were arranged in six parallel series, a still more powerful light was produced.
According to
Fizeau and
Foucault, the intensity of the electric light with a battery of 46 pairs of
Bunsen burners was 235, that of the sun being taken at 1,000, while with 80 pairs it was but 238.
During the excavation of the docks at
Cherbourg two apparatus of this kind were employed, maintained by a single battery of 50 pairs of
Bunsen, affording sufficient light for 800 workmen.
The magneto-electric light was applied for illuminating the lighthouse at
Dungeness, England, in 1862, and was introduced at La Heve,
France, a year or two later.
The machines employed at each are very similar in construction and entirely so in principle, the
English apparatus being arranged after the following manner: —
Eighty-eight bobbins or coils of copper wire are wound about an equal number of cores of soft iron, and arranged in two parallel rings, forty-four in each ring, at the circumference of a wheel 5 feet in diameter, their axes being parallel to that of the wheel.
The axes of each set are placed midway between those of the other.
Sixty-six powerful horseshoe magnets are firmly fixed in three rings exterior to the wheel and parallel to each other, twenty-two in each ring, their poles being in the planes of their respective rings, and distant from each other a space equal to that which separates the centers of the bobbins.
The magnets of the several rings are similarly situated upon the circumference, their poles being alternate; but the poles of those in the inner and outer rings face contrary poles in the central ring.
As the wheel is turned, which is effected by connection from a steam-engine working at a power of one and a half to two horses, the cores with their bobbins pass between the successive poles of the fixed magnets, and as the spaces between the bobbins are equal to those between the poles of the magnets, all the bobbins of one ring pass the poles simultaneously; but as these are arranged intermediately between those of the other ring, it follows that while one set of bobbins is passing the poles the other set is half-way between them; thus alternate currents of opposite character are generated in each set of bobbins, the polarity being changed at the moment of polar passage, so that while the current in one set of bobbins is in the middle of its flow the other undergoes a sudden reversal.
By means, however, of “commutators,” all the successively opposite currents are turned in the same direction in the circuit which conveys the electricity to the carbon points; any fluctuations in the strength of the currents are thus compensated so as to render the resulting intensity very nearly constant.
The velocity of rotation imparted to the wheel is about 110 turns per minute, causing nearly 10,000 changes of polarity in that time.
The intensity of the light produced depends on the velocity of rotation, being comparatively feeble at a slow speed and increasing up to a certain point, when an acceleration of the velocity seems rather to diminish than increase the light.
In the
French machine, sixty-four bobbins are
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arranged in four sets, and revolve between five sets of magnets, eight in a set. They are so arranged as to pass the poles of the magnets simultaneously, and a commutator is dispensed with.
This arrangement, by making each of the carbon points alternately the positive and negative poles of the circuit, insures their equal wear, and permits the use of a simpler apparatus for maintaining a uniform distance between them.
The apparatus actually employed at La Heve lighthouse comprised two of the above machines, each driven by a separate engine, affording a light equivalent to 3,500 Carcel burners, or more than six times that of an oil light of a similar class.
Its fog-penetrating power is said to be very superior to that of the latter.
In
Browning's electric light, worked by a battery of six
Grove cells, the principle adopted is to let the carbon points touch each other, and to clamp them in that position, so that the current has to burn an interval between the two points for itself.
In the accompanying cut,
D is a brass rod carrying the upper carbon point, and sliding easily in its vertical bearings by its own weight.
Directly the upper point touches the lower one, the current is established, and the little electro-magnet
A at once pulls down its armature, which clamps the upper brass rod at
B. Directly the current is broken by the wasting away of the carbons, the electro-magnet
A ceases to hold the brass rod, which then falls, and re-establishes the communication.
Professor Tyndal, in his experiments, concealed the electric light in what he termed a
dark-box, in order that all the issuing beams may be emitted at one orifice, and the experiments be the more vivid in the absence of diffused light in the room.
l is the electric lamp, the rays of which are focused at any desired point.
The apparatus is adapted for a large range of experiments, but in the figure is shown with
Tyndal's
ray-filter c, in which the luminous rays are filtered out by passing the beam through an opaque solution of iodine in bisulphide of carbon, while the invisible heating or ultra-red rays are transmitted.
A current of cool water circulates in the jacket on the outside of the cell to keep the volatile bisulphide cool.
p represents a piece of blackened platinum held in the focus of the mirror to be heated to redness by the invisible heat-rays, although no light passes out through the solution.
The electric light on the
Victoria tower of the
British Houses of Parliament at
Westminster is generated by a Gramme magneto-electric machine, driven by an engine in a vault of the House of Commons, and connected with the signaling-point by two copper wires half an inch in diameter and 900 feet long.
The machine consists of a permanent horseshoe-magnet, between the poles of which revolves an electro-magnet, consisting of a ring of soft iron round which is wound an insulated conducting wire, continuous, but disposed in sections.
The light apparatus is placed within a lantern 5 feet high, 4 feet wide, and having a semicircular glass front, and the light may be directed in a horizontal are of 180°. Two lamps are used alternately, the carbon-points lasting four hours. Expense, twenty cents per hour.
E-lec′tric log.
An electric circuit through the log-line to the detent of an escapement in the register-log, so that by touching a key on deck a circuit may be completed, an armature attracted, and thus the starting and stopping of the mechanical register in the log be exactly timed.
See log.
E-lec′tric loom.
In 1852 an electric loom was exhibited by Bonelli at
Turin.
The invention was at that time in a crude state, but has since been much improved.
The object is to dispense with the perforated cards required in the Jacquard apparatus.
For this purpose, an endless band of paper covered with tin-foil is used, on which the required pattern is traced with a varnish, rendering the parts thus covered nonconducting.
This band is caused to pass under a series of thin metallic teeth, each connected with a small electromagnet, which operate a series of pistons that open or close the holes in a perforated metallic plate (answering to the Jacquard card), through which pass the needles governing the hooks by which the warpthreads are lifted or let fall, according as the electromagnets are in action by contact of the teeth with the metallic surface of the band, or inoperative by contact with the varnish.
E-lec′tric Me′ter.
See electrometer ; electroscope.
E-lec′tric Pen′du-lum.
The ordinary element of an electric clock.
A point below the bob of the pendulum passes through a globule of mercury, the time of contact being indicated on a traveling fillet of paper.
In another form the bob comes in contact, at the limit of each stroke, with a delicate spring, which makes the electric connection.
Besides its use as a chronograph for recording atmospheric, astronomical, and other observations, it is also employed to secure isochronous beats of distant pendulums.
A mode of keeping distant chronometers in exact simultaneous pulsation by which longitude may be exactly determined; the invention of
Dr. John Locke of
Cincinnati.
E-lec′tric Pi-a′no.
One provided with a series of electro-magnets, each corresponding to a key of
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the instrument, the armatures of which are caused to strike the keys when the circuit is closed.
This may be effected by means of perforated cards through which pins are caused to pass and again retracted in any required sequence, after the manner of the Jacquard apparatus.
The device may be connected with a number of instruments at great distances apart, so that they may be caused to play the same tune simultaneously.
In 1868, a contrivance on this principle for playing the organ was exhibited in
London.
It was operated by means of a keyboard, and by enabling the performer to be placed at some distance from the instrument it was claimed that he was better able to judge of its tones, so as to play with more effect.
E-lec′tric Rail′way-sig′nal.
A device for communicating messages or warnings as to the place or condition of a train on the track, in regard to stations left or approached, or to other trains on the same line.
1. An automatic signal operated by the wheel on the track to indicate the passage of a given point by a train, to signal the approach to a crossing in advance; or to the rear, to show the distance of a preceding train; or to signal to a station the position of trains on a track.
2. To enable an operator on a car to communicate with a station at a distance, or with an observer or operator on another train on the same line.
3. To communicate between parts of the same train, as between the conductor and engineer, etc.
E-lec′tric Reg′u-lator.
A device by which an electro-magnetic circuit is made the means of reaching a machine to stop it or start it. The applications are numerous and various.
In gas-lighting by electricity, the gas-cock at a distance is turned by a succession of impulses derived from a battery, communicated through a wire circuit, and imparted to an armature connected with the plug or valve.
As a means of controlling machinery at a distance, the electric circuit, by its magnetic power, affords means for putting a detent into action or removing it.
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Electric steam-gage. |
Stop motions in machinery are also made effective by electric connection, as, for instance, in spinning and knitting machines, when the breaking of a thread allows a metallic arm to drop, and this comes in contact with a tongue, and makes a connection which turns a band on to a loose pulley or otherwise.
E-lec′tric Sig′nal.
One in which visual, palpable, or audible signals, by simple or repetitive sounds or by code, are conveyed by electric influence.
The motion of bell-hammers, of flags, index-fingers, or semaphoric arms may be held as included in this definition, which thus covers telegraphing and signaling by electric circuit.
By a not distant connection, storm-signals and time-balls of observatories may be held as included.
E-lec′tric Steamgage.
A steam-boiler attachment, in which the rise of the mercury under pressure of steam is indicated by means of electric connection to the dial.
In the example, the galvanic battery and index are connected with the mercury column by means of insulated points on the tube, so that the index will signal each successive pound of pressure upon the dial, which has corresponding points.
The completion of the circuit also sounds an alarm by attracting the armature on the hammer-shaft.
E-lec′tric switch.
A device for interrupting or dividing one circuit and transferring the current or a part of it to another circuit.
See switch. A
commutator. See
Culley's “Handbook of telegraphy,”
London, 1870, pp. 199-203.
E-lec′tric Tel′e-graph.
That form of electric signaling apparatus in which an insulated wire excited by frictional electricity is — or rather was — used to convey messages by sparks or shocks.
For notices of early observations, see electrical apparatus.
Gray, in 1729, experimented with conductors; Nollet soon afterwards sent a shock along a line of men and wires 900 toises in length;
Watson, the learned
Bishop of
Llandaff, in 1745, sent a shock through 12,000 feet of wire, and proved that it was practically instantaneous throughout its length.
He signaled an observer by this means.
A writer in the “Scots' magazine,” in 1753, proposed a series of wires from the ends of which were to be suspended light balls marked with the letters of the alphabet, or bells which were to be moved by an electric current directed to the appropriate wire.
Lesage, at
Geneva, in 1774, actually constructed a telegraph arranged in this manner, the end of each wire having a pith-ball electroscope attached.
Lamond, in 1787, employed a single wire, employing an electrical machine and electroscope in each of two rooms, and thus talking with
Madame Lamond by the peculiar movements of the pith-balls according to an agreed code; and Reusser, in 1794, proposed the employment of letters formed by spaces cut out of parallel strips of tin-foil pasted on sheets of glass, which would appear luminous on the passage of the electric spark.
In 1795,
Cavallo proposed to transmit letters and numbers by a combination of sparks and pauses.
Don Silva, in
Spain, appears to have previously suggested a similar process.
See electrical apparatus.
In 1816,
Mr. Ronalds experimented with a frictional electricity telegraph at
Hammersmith.
The current had to pass through eight miles of wire, and the signals were made by means of light pith-balls.
The reading was effected by dials at each station having a synchronous movement derived from clockwork.
Upon their circumferences the letters of the alphabet were engraved, and a screen with a hole cut through it was arranged at each end of the line, so that only one letter should be visible at a time.
The operator at the transmitting station waited until the letter be wanted came opposite the hole in the screen and then made the signal, causing the divergence of the pith-balls at the instant that the same letter became visible to the observer at the other station through the aperture in his screen.
Betancourt, in 1796, constructed a single-line telegraph between
Madrid and Aranjuez, a distance of twenty-seven miles, in which the electricity was furnished by a battery of
Leyden jars, and the reading effected by the divergence of pith-balls.
It was not, however, until the discoveries of Volta,
Galvani, Oersted,
Ampere,
Faraday, and Henry elucidated the properties of electricity de-
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veloped by the voltaic battery, that a practical, continuously working instrument was feasible.
Following these discoveries came the practical instruments and codes of the no less illustrious
Morse,
Wheatstone, and others.
See voltaic pile ; galvanic battery ; electro-magnetic telegraph.
E-lec′tric time-ball.
A balloon of canvas suspended on a mast, and dropped at an exact time every day by means of an electric circuit operated by an observer whose eye is upon the astronomical clock, and hand upon the telegraph-key.
E-lec′tric torch.
A gas-lighter operating by electric action.
An
electrophorus.
E-lec′tric wand.
An electrophorus in the shape of a baton.
See Electr Phorus.
E-lec′tric watch-clock.
A watchman's timedetector, in which a patrol touches a stud at such times during the night as may indicate his presence at that spot at the appointed hour.
Touching the stud completes an electric connection and makes a mark upon a traveling time-paper.
E-lec′tric Weigh′ing-appa-ra′tus.
An attachment to a scale which comes in as an auxiliary to the eye in detecting the turn of the scale.
The poise is shifted out on the beam, and as soon as it feels the tendency to rise the circuit is completed, and the point at which the poise stopped is indicated.
E-lec′tric Whal′ing-appa-ra′tus.
A means whereby a bursting-charge in a harpoon may be exploded.
See electric harpoon.
E-lec′tro-bal-lis′tic Appa-ra′tus.
An instrument for determining by electricity the velocity of a projectile at any part of its flight.
The projectile passes through a wire screen, thus breaking a current of electricity, and setting in motion a pendulum, which is arrested on the passage of the projectile through a second screen.
The distance between the screens being known, the are through which the pendulum vibrates measures the time due to the projectile's flight between the screens.
See chronograph ; ballistic pendulum.
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Electro-ballistic pendulum. |
E-lec′tro-bal-lis′tic Pendu-lum.
Fig. 1848 1 is an elevation and 2 a section of the apparatus used in the
United States Ordnance Department.
The pendulums
a b are suspended from the same axis, and are so adjusted that when each is brought to a horizontal position at the 90° mark on each side of zero at the middle of the are
c and let fall, they will meet precisely at the center.
The bob of the inner pendulum
b is provided with a marking point, the outer end of which is struck by a blunt projection on the outer pendulum
a, when the two pass each other, impressing a mark on a sheet of paper clamped to the are. See chronograph.
E-lec′tro-blast′ing.
Blasting by means of an electric or electro-magnetic battery, communicating through connecting wires with the charges of powder.
It was first tried in blowing up the sunken hull of the “Royal George,” in 1839, by
Colonel Pasley.
In 1840 the plan was used in
Boston Harbor by
Captain Paris.
In 1843, by
Cubitt, for overthrowing a large section of Round-down Cliff,
Kent, England, in making a portion of the
Southeastern Railway.
The mass dislodged weighed 400,000 tons.
See blasting.
E-lec′tro-chem′i-cal Tel′e-graph.
A telegraph which records signals upon paper imbued with a chemical solution, which is discharged or caused to change color by electric action.
Nicholson and
Carlisle discovered, in 1800, that water was decomposed by the voltaic pile, hydrogen being evolved at the negative and oxygen at the positive end of the wire.
Davy, afterwards
Sir Humphry Davy, by the aid of the apparatus of the
Royal Institution at
London, the most powerful then in existence, proved by a series of experiments, commencing in 1801, that many substances hitherto considered as elementary bodies could be decomposed by voltaic action, and succeeded in 1807 in resolving the fixed alkalies soda and potash.
Faraday, 1833, besides his extensive additions to the science of electro-magnetism, established the fact that the chemical power of a current of electricity is in direct proportion to the absolute quantity of electricity which passes; and farther proved that the quantities required for decomposing compound bodies were proportional to the atomic weights of
Dalton.
Bain's telegraph (1845) was the first in which these scientific facts were so applied as to lead to any practical result.
In this, a solution of ferro-cyanide of potassium in water, to which are added two parts of nitric acid and two of water, is employed.
With this long strips of paper are saturated, which being drawn between a metallic roller and stylus operated by means usual in electro-telegraphy, — dispensing, however, with relay-magnets, — dots and dashes are produced, as in the
Morse system.
These appear of a blue color, in consequence of the ferro-cyanide of potassium being converted into cyanide of iron by electric action and contact of the iron stylus with the paper.
Bakewell subsequently improved the construction of this instrument, and added an electro-magnetic governor, to obtain synchronism in the movements of the apparatus at the two ends of the line.
Gintl, a German, in his method, also dispenses with the relay, and records messages by the line-current direct.
He prepares his paper with a solution of one part iodide potassium and twenty starch-paste in forty parts of water.
The iodine being set free colors the starch blue.
Bonelli's telegraph (1860) records a fac-simile of the transmitted message on mechanically prepared paper.
The message is set up in type, which are arranged in a box at one side of a carriage that traverses from end to end of a table, and passes back and forth under a bridge placed transversely thereto.
The type occupy the lower left-hand side of the carriage, and at the upper right-hand side is placed a strip of the paper.
Immediately over the type are five movable teeth, insulated from each other and connected by five wires with a similar number of styles at the receiving apparatus.
As the carriage with the types face upwards comes under the bridge, the teeth come lightly in contact with their raised portions, closing the circuit so long as the metallic contact lasts.
Thus letter after letter is transmitted.
On the right side of the bridge is a writing-comb composed of five teeth made of platinum-iridium alloy, which is not subject to corrosion, insulated from each other and pressing lightly on the paper strip beneath.
This would produce, if each tooth were simultaneously
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traversed by the electric current, five parallel lines on the paper; but as the current only passes to each during the time when some portion of a type is beneath the corresponding tooth of the type-comb at the sending station, they only produce lines at such intervals and of such length as are determined by the form of the type; cavities in the letters and spaces between letters and words being represented by the discontinuation of one or more of the lines.
The wagon is moved by a cord and weight, and is secured at one end of the carriage by a hook, which is released by an electro-magnet when a current is sent over the wires.
Those at each end of the line are adjusted to traverse their respective carriages in equal or nearly equal times.
The paper intended for receiving permanent printing is prepared by being saturated in a solution of nitrate of manganese, which, under the action of the current, leaves a light brown mark.
Fugitive printing, as for the press, is done on paper prepared with iodide of potassium, which affords at first an iodine color, but is liable to fade.
It is said that a speed of 300 in permanent, and of 1200 words in fugitive, printing per minute is attainable by this apparatus.
See electro-magnetic telegraph ; autographic telegraph.
E-lec′tro-chron′o-graph.
An instrument used for recording time and occurrences in the instant and order of their time, as in noting transits in observatories.
A paper marked for seconds is placed on the surface of a revolving drum, over which is a stylus operated by electro-magnetic action when the circuit is closed by the telegraph key in the hand of the operator, who is also the observer at the transit instrument.
A mark is thus made on the time-paper at the instant of the occurrence of the transit.
E-lec′trode.
Either of the poles of the voltaic circle.
The positive, +, electrode is the
anode; the negative, —, the
cathode. The terms are
Faraday's.
E-lec′tro-dy-nam′ic En′gine.
An engine in which a dynamic effect is produced by the evolution of an electric current, by voltaic battery or otherwise.
See electro-magnetic machine.
E-lec′tro-en-grav′ing.
Engraving executed by means of electricity.
A form of etching.
E-lec′tro-etch′ing.
A process for biting — in an engraving by attaching it to the copper of the battery in an electro-bath.
The plate is covered with a ground and etched in the usual manner; being immersed for a while in the bath, it is withdrawn and the fine lines
stopped-oit; a second immersion deepens the lines and makes the next tint, and so on.
E-lec′tro-gild′ing.
A thin deposition of gold by voltaic action on an object placed in a bath of a salt of the metal.
See electro-plating.
E-lec′tro-lyte.
The compound in the electroplating bath which is decomposed by the electric action.
E-lec′tro-mag′net.
A bar of soft iron rendered temporarily magnetic by the passage of a current of electricity through a coil of wire by which the bar is surrounded.
The electro-magnet of the Stevens Institute of Technology weighs in all about 1,600 pounds; eight brass spools, each of which is wound with 272 coils of copper wire insulated with
kerite. The hollow spools contain cores of
Norway iron, four to each core.
The lifting-force of the magnet is from thirty to fifty tons.
E-lec′tro-mag-net′ic A-larm′.
One which is brought into action by the closing an electro-magnetic circuit.
This may be a burglar-alarm in which the opening of a door or window is made to close a circuit mechanically; or it may be a fire-alarm in which the lengthening of a rod or a change in its shape is made to close a circuit.
In some cases, a column of mercury is expanded by the heat and thus completes the circuit, the coil
b attracting the armature and releasing the detent of the wheel
k, which is then revolved by the weight
i and cord
h, and vibrates the hammer-shaft, delivering a blow upon the bell.
By this means the hammer may be made to give a repetitive alarm, like that of a clock, as a warning, or the instrument may be used as a signal, each closing of the circuit by means of a key giving a single blow.
See fire-alarm.
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Electro-magnetic alarm. |
E-lec′tro-mag-net′ic clock.
These clocks are of two kinds: —
Those in which the motive-power is derived from electric action.
Invented by
Wheatstone.
Those which are operated by the usual means, but are made the medium by mechanical devices of driving or regulating other clocks to which they are connected by an electric circuit.
1. In
Bain's clock the pendulum, at each vibration, moves a light slide by which the electric circuit is alternately completed and broken, and by which magnetism is alternately conferred upon and abstracted from a coil inclosed in a heavy hollow brass case which constitutes the bob of the pendulum.
On either side of the pendulum are the poles of two permanent magnets, which alternately attract and repel the coil of the bob, according to its magnetized or demagnetized condition.
A clock of this kind has been kept in motion by electric currents derived from a zinc plate buried in damp earth.
Shepherd's electro-magnetic clock was shown at the
London Exposition, 1851.
In this clock electromagnetism is the sole motor in moving the pendulum, driving the train, and running the strikingworks, no weights or auxiliary springs being employed.
The pendulum in its oscillations makes and breaks an electric circuit, which alternately magnetizes and demagnetizes a horseshoe-magnet, which in its active condition attracts an armature and raises a lever which is caught by a detent-latch.
On the break-
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ing of the circuit, the armature is released, the latch lifted, and the weighted lever strikes the pendulum to give an adequate impulse to maintain its motion.
This is repeated at each oscillation.
Besides the circuit just described, which maintains its own action, the pendulum makes and unmakes another circuit which actuates a ratchet-wheel, propelling it at the rate of a tooth to each second, the axis of this ratchet-wheel operating the remainder of the train.
The circuit of the
striking part is only completed once in an hour, and operates an armature to pull the ratchet-wheel attached to the notched strikingwheel one tooth forward every two seconds, and each tooth is accompanied by a blow on an electromagnetic bell.
The number of blows depends upon the notched wheel, the spaces in the circumference of which are adapted to the number to be struck; and when this is complete, a lever falls into the notch, and in so doing cuts off the electric circuit till the recurrent period again stirs the striking-parts into activity.
2. The other form of electro-magnetic clock is designed to obtain isochronous action among a number of clocks in different portions of a building or a town.
Fixed upon the arbor or axis of the second-wheel of a clock is a wheel of metal, the circumference of which is divided into sixty alternating divisions of metal and of ivory, the former being a conductor and the latter a nonconductor of electricity.
A small platinum peg is kept in contact with this divided edge, so as, by the revolution of the wheel, to be alternately in contact with the conducting and nonconducting surfaces, and so connected with a voltaic series as to alternately admit and resist the passage of an electric current.
The electric circuit thus becoming pulsative is caused by local magnets and armatures to actuate an apparatus stationed at any point to which the wires may be carried, giving motion to a wheel and axle, and causing it to revolve so as to indicate seconds, and the other motion-work of a clock.
By this means isochronous pulsations of seconds are maintained at all the points connected with the regulator, and thus perfect uniformity is established at all the clocks of a city, capitol, or private establishment.
Dr. Locke of
Cincinnati, about 1848, invented the method of obtaining isochronous vibration of pendulums by electric connection.
Congress awarded him a premium of $10,000 for the invention, designing to use it in astronomical researches and determining longitudes.
E-lec′tro-mag-net′ic Engine.
The action of a current of electricity converts a piece of soft bariron into a magnet, and the breaking of the circuit restores the iron to an inert condition.
This transition — alternate excitement and prostration — has been frequently utilized to confer a pulsative movement upon an armature, whose motion in one direction is obtained by the attraction of the magnet and the reflex action by a spring or weight in the intervals of electric excitement of the iron.
So far the chronicler has little to record of valuable effect derived from this engine, though its power is demonstrable.
At present the authorities declare it is resolved into a question of the relative costs of zinc and coal.
The case is thus stated in the American Artisan : —
The chemical action in the galvanic battery is the source of power in electro-magnetic engines, just as the rapid chemical action called combustion in the furnace of a steam-engine is the source of power there.
Chemical affinity, or the tendency of two bodies to combine chemically, is a sort of potential energy which, when the substances actually do combine, is replaced by actual energy in the form of heat or of current electricity, or of both combined; and this may be converted into mechanical energy.
In a Daniells battery, the liquid in the cells being a solution of a sulphate of copper in water, the total heat produced by the solution of one pound of zinc is 3,006 thermal units; 2,342 being produced by the oxidation of the zinc, and 664 being produced by the combination of the oxide of zinc with sulphuric acid.
The total heat consumed is 1,419 thermal units; 527 being consumed in decomposing sulphate of oxide of copper, and 1,060 being consumed in decomposing the oxide of copper.
The total quantity of heat developed is, therefore, 3,006 less 1,587, equal to 1,419 thermal units; and this quantity multiplied by 772 foot-pounds, the mechanical equivalent of heat, gives 1,095,468 foot-pounds for the amount of energy developed by the solution of one pound of zinc in a Daniells battery.
This is less than the total energy developed by the combustion of one pound of carbon.
In a Smee's battery, the liquid in the cells being dilute sulphuric acid, the heat produced by the combination of one pound of zinc with oxygen and sulphuric acid is, as before, 3,006 thermal units, and the total heat consumed is 2,106 thermal units; about 200 being consumed in separating water from sulphuric acid, and 1,906 being consumed in decomposing water.
The total amount of heat developed, therefore, is 3,206 less 2,106, equal to 900 thermal units, which are equivalent to 694,800 foot-pounds of mechanical energy derived from the solution of one pound of zinc in a Smee's battery.
This is about one sixteenth part of the energy developed by burning one pound of carbon.
It is certain that the efficiency can be made to approximate much more nearly to unity, the limit of perfection, in electromagnetic engines than in steam-engines.
At present, however, the ratio of their efficiencies can only be roughly estimated; and it may be considered as a favorable view toward electro-magnetic engines to estimate their greatest possible efficiency as four times that of the best steam-engines.
Taking this into account along with the previous calculations, and it appears that the work performed per pound of zinc may be estimated at four tenths of the work per pound of carbon in steam-engines when the solution used in the cells of the battery is sulphate of copper; and at four sixteenths, or one fourth, of the work per pound of carbon in steam-engines when dilute sulphuric acid is used in the cells of the battery.
Before, therefore, electro-magnetic engines can become equally economical with heat engines as to cost of working, their working expense per pound of zinc consumed must fall until it is from four tenths to one quarter of the working expense of one of the most economical steam-engines per pound of carbon or of coal equivalent to carbon.
The price of zinc, however, being so much greater than that of coal, it is evident from these facts and calculations that electro-magnetic engines never can come into general use except in cases where the power required is so small that the cost of material consumed is of no practical importance, and the situation of the machinery is such as to make it very desirable to have a prime mover without a furnace.
According to
Mr. Joule, the consumption of a grain of zinc, though forty times more costly than a grain of coal, produces only about one eighth of the same mechanical effect.
Cazal's electro-magnetic machine resembles a flywheel, being a thick disk of soft iron cut into the
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shape of a gear-wheel and having a circumferential groove wound with insulated wire, whose ends are soldered to insulated thimbles, which, by means of tangent springs, introduce the battery current.
Surrounding this magnetic wheel is a fixed, heavy iron ring insulated on its interior surface in a manner to present elevations corresponding to the teeth of the wheel.
When the teeth of the wheel pass before the prominences of the ring, there is a near approach to contact, and the attraction is strong.
The attractions are balanced when the teeth are midway.
At the moment of nearest approach the current is arrested; it is renewed when the teeth are midway; the momentum of the wheel carries it over the point of equal attractions.
The Birmingham Company's (
English) electromotor has four sets of fixed electro-magnets of the horseshoe form, two sets at each end of an oscillating beam by which the power is to be utilized.
The magnets of each set are arranged in two tiers, one above the other.
The armatures of these several magnets are carried by rods depending from the ends of the beam; but the rods pass freely through these armatures without being fastened to them.
When, therefore, an armature, in the descent of the rod, comes into contact with the magnet to which it belongs, the rod continues its motion and leaves the armature resting there.
In the return motion the rod lifts the armature again, by means of a collar or enlargement which has been given to it at the place intended.
In the action of the machine, the battery current actuates the magnets on the side of the descent, while on the other side the current is cut off. The machine acts, therefore, only by attraction.
As the armatures approach their magnets successively, it happens that whenever one becomes inefficient, by coming into contact with its magnet, the next will be in position to exert a very high attractive force, and this force increases until this next makes contact with its magnet in like manner.
Kravogl's electro-magnetic engine is a heavy wrought-iron wheel rotated by the creeping up inside it of a permanent magnet, which displaces the center of gravity, and by the preponderance of the side rotates the wheel.
Another form of the engine has two powerful helixes of insulated copper wire, within which are two heavy cylinders of soft iron counterbalanced on the ends of a beam, like the working beam of a steam-engine.
By the working of an eccentric on the main or fly-wheel shaft these insulated helixes are alternately connected and disconnected with the opposite sides of a galvanic battery so as to magnetize and demagnetize alternately the two helixes, and so drawing first one and then the other of the soft
bar-iron cylinders into them with a force of many hundred pounds. In some machines of this description 10-horse power has been obtained.
Page's reciprocating engine (
Fig. 1850) consisted of two electro-magnets, the armatures of which are connected by a bar moving upon centers, the bar is connected with the beam, which, by means of a crank, moves the fly-wheel; by means of a breakpiece upon the axle of the fly-wheel, the current is alternately passed through the two magnets.
A double-beam engine of similar construction, operated by two pairs of electro-magnets, has also been made.
About 1849,
Professor Page propelled a car on the track of the
Baltimore and Washington Railroad from
Washington to
Bladensburg, a distance of six miles, and back, by means of an engine of his invention, attaining a speed of nineteen miles an hour.
Various forms of electro-magnetic engines have also been invented by
Wheatstone,
Talbot, Hearder, Hjorth, and others.
Professor Jacobi of
St. Petersburg, in 1838-39, succeeded in propelling a boat upon the
Neva at the rate of four miles an hour, by means of a machine on this principle.
The boat was 28 feet long, about 7 feet wide, drew about 3 feet water.
The battery used consisted of sixty-four pairs of plates, and propelled the boat by paddlewheels.
He also applied his engine to working machinery, but without decided success.
 |
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Page's electro-magnetic engine. |
In 1842,
Davidson constructed an electro-magnetic locomotive-engine which attained a speed of about four miles an hour on the Edinburgh and Glasgow Railway.
E-lec′tro-mag-net′ic ma-chine′.
See electro-magnetic engine.
E-lec′tro-mag-net′ic Reg′u-la-tor.
A device for maintaining an even heat in an apartment, a bath, or a furnace.
See thermostat.
E-lec′tro-mag-net′ic Tel′e-graph.
A signaling, writing, printing, or recording apparatus in which the impulses proceed from a magnetic force developed by voltaic electricity.
A mass of soft iron is rendered temporarily magnetic by the passage of a current of electricity through a surrounding coil of wire.
It differs from the
electric telegraph properly considered, and also, specifically, from the magneto-electric telegraph (which see). See also list under telegraph.
Three discoveries necessarily preceded the invention of the electro-magnetic telegraph: the properties of the magnet, the modes of developing frictional electricity, and voltaic electricity.
The earlier electric telegraphs were all what their name implies, and not
electro-magnetic. See electric telegraph.
To save repetition, reference is here made to magnet, electricity, electric telegraph, voltaic pile, galvanic battery, for the precedent discoveries and inventions which are the foundation of the electro-magnetic telegraph.
In 1808, Sommering described a system invented by him, based upon the decomposition of water by the voltaic pile, embracing a number of wires equal to that of the alphabet and the numerals, and leading into glass tubes containing water, the bubbles of gas from which, when the electric fluid was conducted into them, served as signals.
Professor Coxe, of
Pennsylvania, about the same time suggested telegraphing by means of the decomposition of metallic salts.
Oersted, in 1820, after many years' research into the action of the voltaic current on magnets, announced the fact that the magnetic needle was deflected by such current, exhibiting a tendency to place itself at right angles to the wire through which the current passes; and
Faraday discovered in 1821 that the magnet would revolve about the conducting wire, or the latter about the magnet.
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The experiments of Oersted, farther extended by
Ampere, and the discovery by
Faraday that magnetism was induced in a bar of soft iron under the influence of a voltaic circuit, led the way to the invention of the first really convenient and practical system of electro-telegraphy.
In 1825,
Mr. Sturgeon, of
London, discovered that a soft iron bar, surrounded by a helix of wire, through which a voltaic current is passed, becomes magnetized, and continues so as long as the current is passing through the wire.
In 1832,
Baron Schilling constructed a model of a telegraph which was to give signals by the deflection of a needle to the right or left.
One great practical difficulty was still to be overcome, the resistance of the transmitting wire to the comparatively feeble current engendered by the voltaic battery.
This was conquered by
Professor Joseph Henry, now secretary of the Smithsonian Institution at
Washington, who, in 1831, invented the form of magnet now generally used for telegraphic purposes, and discovered the principle of “
combination of circuits, constituting the important invention of
receiving-magnet, and the
relay or
local battery, as they are familiarly known in connection with
Morse's telegraph.
The effect of a combination of circuits is to enable a weak or exhausted current to bring into action and substitute for itself a fresh and powerful one.
This is an essential condition to obtaining useful mechanical results from electricity itself, where a long circuit of conductors is used.” — Prescott,
History of the Electric Telegraph.
In 1832,
Professor Morse began to devote his attention to the subject of telegraphy; and in that year, while on his passage home from
Europe, invented the form of telegraph since so well known as “
Morse's.”
A short line worked on his plan was set up in 1835, though it was not until June 20, 1840, that he obtained his first patent, and nearly four years elapsed before means could be procured, which were finally granted by the government of the
United States, to test its practical working over a line of any length; though he had as early as 1837 endeavored to induce Congress to appropriate a sum of money sufficient to construct a line between
Washington and
Baltimore.
Professor Morse deserves high honor for the ingenious manner in which he availed himself of scientific discoveries previously made by others, for many important discoveries of his own, and for the courage and perseverance which he manifested, in endeavoring to render his system of practical utility to mankind by bringing it prominently to the notice of the public; and he lived to see it adopted in its essential features throughout the civilized world.
In the mean while
Gauss and
Weber, and after them Steinheil, in
Germany, were at work, and constructed a short line between the Royal Academy at
Munich and the observatory; this, by means of right and left hand deflection-needles, was caused to print dots on a continuous slip of paper, moved by clock-work.
While making experiments in connection with this work, Steinheil made the important discovery that the earth might be used as a part of the circuit, thus enabling him to dispense with one half the length of wire which was thought requisite.
The attention of
Wheatstone, in
England, appears to have been drawn to the subject of telegraphy in 1834.
Morse's first idea was to employ chemical agencies for recording the signals, but he subsequently abandoned this for an apparatus which simply marked on strips of paper the dots and dashes composing his alphabet.
The paper itself is now generally dispensed with, at least in this country, and the signals read by sound, — a practice which conduces to accuracy in transmission, as the ear is found less liable to mistake the duration and succession of sounds than the eye to read a series of marks on paper.
Bain, in 1846, patented the electro-chemical telegraph which dispensed with the relay-magnet at intermediate stations; and subsequently Gintl, in
Austria, and Bonelli, constructed telegraphs of this class, varying in details from that of
Bain.
See electro-chemical telegraph.
Wheatstone's first telegraph comprised five pointing needles and as many line wires, requiring the deflection of two of the needles to indicate each letter.
His first dial instrument was patented in 1840; modifications were, however, subsequently made in it. The transmission of messages was effected by a wheel having fifteen teeth and as many inter-spaces, each representing a letter of the alphabet or a numeral, and thirty spokes corresponding to these, and forming a part of the line.
The circuit was closed by two diametrically opposite springs, so arranged that when one was in contact with a tooth the other was opposite a space, when the transmitter was turned until opposite a particular letter, and held there, a continuous current being produced, causing an index on the indicating dial at the other end of the line, which had thirty divisions, corresponding to those of the transmitter, to turn until it arrived opposite the letter to be indicated.
The revolution of the index was effected by clock-work, the escapement of which was actuated by an electromagnet at either end of a pivoted beam, the ends of which carried two soft-iron armatures.
One of the line wires, as well as one of the contact springs of the transmitter, and one of the electro-magnets of the indicator, was afterwards dispensed with.
A magneto-electric apparatus was subsequently substituted for the voltaic battery.
The single-needle telegraph of
Cook and
Wheatstone is caused to indicate the letters and figures by means of the deflections to the right or left of a vertical pointer; for instance, the letter A is indicated by two deflections to the left, N by two deflections to the right, I by three consecutive deflections to the right, and then one to the left, and so on. This is extensively employed in
Great Britain and in
India.
The same inventors have also contrived a double needle-telegraph on the same plan; but this, as it requires two lines of wire, each needle being independent of the other, though greatly increasing the speed with which messages may be transmitted, has not come into general use.
Dr. Siemens, of
Berlin, invented an apparatus by which the armatures of the electro-magnets at each end of the line were caused to vibrate synchronously, maintaining the motion of scape-wheels carrying pointers traversing a lettered dial, so that, the vibrations of either armature being checked, the pointers at either end of the line would simultaneously point to the same letter.
House, about 1845, invented a telegraph which printed the letters of the
Roman alphabet on a strip of paper, and was at one time extensively used in the
United States.
It comprised a lettered disk, operated in much the same way as that of
Wheatstone, from keys arranged like those of a piano, and a receiving-apparatus, which included a scape-wheel, an anchor escapement, controlled by the movements of the lettered disk, and actuating a slide-valve which operated the piston of a compressed-air cylinder by
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which a wheel carrying type on its periphery was turned so as to present the appropriate letter indicated at the transmitting station to the paper slip which was by suitable mechanism drawn to the type-wheel to receive an impression.
Professor Hughes has also invented a very ingenious printing-telegraph, depending upon the synchronous revolutions of two or more type-wheels at different stations.
See printing-telegraph.
Various forms of dials or pointer telegraphs have been devised by Breguet in
France,
Siemens and Halske and
Kramer in
Germany, and various improvements in the details of construction by numerous others which the limits of this article will not permit us even to refer to. See specific index under telegraph.
E-lec′tro-mag-net′ic watch-clock.
An apparatus consisting of a magnet, with a recording-dial, clock-works, and a signal-bell; from this run wires, one to each of the banks or other offices under guard where watchmen are employed, whose duty it is to visit each bank at stated times during the night and give signals, which are recorded on the dial of the clock in the fire-alarm office, showing the time that the signal was given from any particular bank or office.
If the signal is not given within five minutes after the appointed time, the man on duty at the firealarm office communicates with the office of the superintendent of police, and an officer is immediately despatched to the point from whence no signal has been sent.
E-lec′tro-medi-cal Appa-ra′tus.
An instrument for the treatment of diseases by electro-magnetism.
Great success in this line was announced by
Johannes Francisco Pavate, at
Venice, in 1747.
The details of the apparatus employed by him are not known.
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Electro-Medical apparatus. |
From that time to the present the treatment of diseases by electrical appliances has undergone its vicissitudes in public favor, becoming notably prominent after the discovery of voltaic electricity and of the properties of electro-magnetism.
The latter is now generally adopted.
Fig. 1851 shows a machine designed for medical purposes.
It is operated by a single-cell Daniells battery, the current from which, after passing through a helix, is conducted by wires provided with insulating handles to any part of the person to which it is desired to apply the treatment.
In the instrument shown in
Fig. 1852 two small coils, connected with each other and furnished with a vibrating contact-breaker, are traversed by the currents from a small battery.
The coils are surrounded by hollow cylinders of copper or brass in which induced currents are generated.
These may be slipped on or off the coils, to intensity or moderate the strength of the current, which is directed by appropriate wires to the parts under treatment.
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Electro-Medical machine. |
E-lec-trom′e-ter.
An instrument to measure the amount of an electrical force.
In
Coulomb's torsion electrometer (
a) the force opposed to that of electricity is the resistance to twisting offered by an elastic thread.
In
Henly's quadrant electrometer (
b) the electric force is measured by the amount of repulsion which it produces upon a pith-ball attached to a silk fiber suspended from the center of a graduated are.
c is the gold-leaf electroscope.
See electroscope.
Sir William Thomson's and
Varley's electrometers are the most delicate of all, and are used in reading the insulating power of telegraph-cables.
See galvanometer.
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Electrometers. |
The strength of the electric force excited by the rubbing of glass, sulphur, amber, wax, resin, etc., was measured by
Gilbert by means of an iron needle (not very small) moving freely on a point,
versorium electricum; very similar to the apparatus employed by Hauy and
Brewster, in trying the electricity excited in different minerals by warmth and friction.
E-lectro-mo′tor.
An exciter of electric action.
An apparatus actuated by electricity and imparting motion to a machine.
See electro-magnetic machine.
E-lec′tro-neg′a-tive.
Having the property of being attracted by an electro-positive body, or a tendency to pass to the positive pole in electrolysis.
E-lec′tro-nome.
A measurer of electricity.
See electrometer.
E-lec-troph′o-rus.
An instrument invented by Volta, for generating electricity by induction, about 1776.
Volta's electrophorus (
A,
Fig. 1854) consisted of a thick disk of resin 12 or 15 inches in diameter, called the
plate, resting on a tin foil called the
sole. The plate has a metallic cover, insulated by a glass handle.
The resinous plate being excited by rubbing it with a warm and dry flannel, the metallic cover is placed upon it, and a spark of — electricity may be drawn from it; if it then be raised, it affords a spark of + electricity.
On replacing the cover and again
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touching it, it affords another spark of — electricity, and so on.
It forms a portable electrifying-machine, and is used as a gas lighter by developing a spark over the burner, inflaming the issuing gas.
The electrophorus
B has a metallic bell lined with fur or wool, and a hard-rubber handle.
It has also an interior bell of hard rubber with a metallic pedestal and foot.
The act of raising the metallic bell generates frictional electricity, and the bell being brought into contact with an insulated chain attached to a burner develops a spark over the latter, thus lighting the gas.
 |
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Electrophorus. |
In the electric wand
C, the electricity is generated by a metallic tube sliding in a fur-lined reservoir of hard rubber, and is applied, as the bell just described, by establishing a circuit except at a short break over which the spark jumps.
Another wand carries a Leyden jar.
E-lec′tro-pho-to-mi-cog′ra-phy.
The art of photographing objects as magnified by the microscope by the help of the electric light.
E-lec′tro-plat′ing.
A means of covering a metal or a metallic surface by exposure in a bath of a solution of a metallic salt, which is decomposed by electrolytic action.
Early in the present century, Volta demonstrated that a solution of a metallic salt, under the influence of the voltaic pile, became immediately reduced to its elements, in such a way that the metal was deposited at the negative pole.
This was regarded as an interesting fact, of some moment to electricians, but not of special interest in the arts.
“Some curious experiments have lately been made by
Mr. Cruickshank of
Woolwich.
On passing the galvanic influence by means of two silver wires through a solution of nitrat of silver, the upper wire became oxidated and gradually corroded, while at the same time a beautiful arborescent precipitation of metallic silver took place on the lower wire.
Acetite of lead and sulphat of copper were similarly decomposed and precipitated on the lower wire.” —
Monthly Magazine, August, 1800.
In 1801, Wallaston demonstrated that a piece of silver in connection with a more positive metal placed in a bath of sulphate of copper became covered with copper and would stand burnishing.
It was not until 1838 that
Mr. Spencer gave it a practical bearing by making casts of coin and casts in intaglio from the matrices thus formed.
Professor Jacobi of Dorpat, in
Russia, had been an independent inventor, and in the same year brought forward specimens which were much admired and caused him to be put in charge of gilding the iron dome of the
Cathedral of St. Isaac at
St. Petersburg.
This dome weighs about 448,000 pounds, and was electro-gilded with 274 pounds of ducat gold.
The process, briefly described, is as follows: —
The voltaic current employed is supplied by a constant battery, such as Daniells's or
Bunsen's. In the simple form, the galvanic current is produced in the same vessel in which the metallic deposit is effected.
The outer vessel
K of glass,
stone-ware, or wood, contains a solution of the metallic salt, — say sulphate of copper.
A smaller vessel
P, of unglazed porcelain, contains diluted sulphuric acid.
A plate of zinc
Z, forming the positive pole, is suspended in the acid solution and connected with the copper medals
m m by means of a copper wire.
Electrolysis ensues, the copper in the solution is deposited on the medal which forms the negative pole, and the strength of the solution is maintained by suspending a bag of crystals of sulphate of copper in the bath.
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Electro-plating apparatus. |
In the compound form the galvanic current is produced outside the bath containing the solution to be decomposed.
In this arrangement a current of any degree of strength may be employed, according to the size and number of cells forming the battery.
A is the battery,
B the vessel into which the solution of the metal to be deposited is placed; the molds are suspended from a metallic rod
a b, opposite to which the plate
f d is hung; copper, if the solution is a salt of that metal, will serve as a soluble electrode, and will be dissolved in the same ratio as the metal is deposited upon the mold.
The battery being charged,
f d is put into communication with the copper pole
C by a copper wire, and
a b is put in communication with the zinc pole
Z.
The voltaie current being passed through the solution of a metal, decomposition takes place, the metal being electro-positive attaches itself in a metallic state to the negative pole or to the object attached thereto, — the medal, for instance, — while the oxygen or other electro-negative element seeks the positive pole.
The
anode is the electrode placed at the positive pole of the battery, which in the electro-chemical decomposition can be dissolved, or which, if it be
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insoluble, attracts oxygen and acids.
The
cathode is the electrode which, placed at the positive pole, receives the metallic deposit, or attracts hydrogen and alkalies.
If the article to be coated be a medal or other object which is a conductor of electricity, the deposit will be made directly upon it; but if it be an engraved wooden block, a wax seal, or a plaster-cast, it is necessary to give it a conducting surface, which is done by brushing it over with black lead or bronze powder.
In obtaining the counterpart of a medal or engraved plate, the latter must necessarily be coated with some substance to prevent adhesion of the matrix.
In the United States Coast Survey a solution of iodine is employed in the duplication of its copper-plates.
In
Shaffner's process, wood, fabric, or fiber is prepared to receive a metallic coating by immersion in a bath containing plumbago in suspension.
Fibrous substances may also be prepared by dipping in a solution of nitrate of silver and ammonia, and exposure to hydrogen gas.
The process of electro-plating has been applied to many substances, as terra-cotta, wood, cloth, lace; and to the ornamentation of book-covers and similar objects; and also for soldering, by uniting the adjacent edges of two pieces of metal by forming a solid mass between them.
The works of a chronometer watch have been electro-plated while going.
When applied to depositing a coat of
silver or
gold upon an article, it is placed in a solution of the required metal, the acid set free in the reaction being such as will act upon the piece of metal whose function it is to keep the metallic solution to its normal strength.
Copper and its alloys and German silver are the metals upon which
gold or
silver are most readily deposited.
Electro-plating with iron has been done in
Russia by a process invented by
Jacobi and
Klein; it is much more durable than copper, and is said to afford good results, having been used by the
Russian government for printing bank-notes.
A
United States patent was granted for this process in 1868.
See also Garnier's process, “Photographic journal,” Vol.
VI., p. 31
et seq.
An important improvement in electro-plating is that of
M. Oudry of
Auteuil, near
Paris, for coating large objects made of iron with a thick layer of copper.
In the old process it was customary to clean the pieces to be plated, and after subjecting them to a weak preliminary bath in order to form a thin film on the surface, to transfer them to a stronger bath, where they were subjected to voltaic action for several days.
In this part of the process it was found that, owing to the strength of the acid bath, and the imperfection of the preliminary coating, the iron was corroded, instead of becoming coated with copper.
The details of
M. Oudry's process have not been made public, but as a preliminary to the plating the articles are covered with three coats of benzine and afterward rubbed with pulverized charcoal, when they are ready for the bath, which is composed of a saturated solution of sulphate of copper.
The battery used is
Daniell's.
The operation requires from three to four days, by which time a deposit about one twenty-fifth of an inch in thickness is formed.
The objects, when removed from the bath, are washed in slightly acidulated water, brushed with a wire brush, and rubbed with paper to brighten them, after which they are brushed with ammoniacal acetate of copper, and finally polished with a hard brush well waxed.
By this process many of the cast-iron monuments in the city of
Paris have been copper-plated, and also the street lamp-posts.
Cast-iron lamp-posts weighing 4 1/2 cwt. plated in this way cost about $40, while those of bronze of similar pattern, though weighing but 2 3/4 cwt., cost $150.
Herr W. Licke, of
Hanover, deprecates the use of the acid bath, and advocates the use of a tartrate with either a soda or a potash salt, especially for coppering iron by means of galvanism.
The best results were obtained with a solution of 20 parts of crystallized sulphate of copper in 160 parts of water, which solution is mixed with 50 parts of neutral tartrate of potash dissolved in 650 parts of caustic soda solution of 1.12 specific gravity.
E-lectro-po′i-on—bat′ter-y.
（
ἐλεκτρον-ποιέω, Gr., electricity-making.) A name applied specially to
Bunsen's carbon battery, though applicable to other forms.
E-lectro—pos′i-tive.
Having a tendency to the negative pole of a magnet or battery.
E-lectro—punct′ur-ing.
Treatment by the insertion of needles in the body, and passing a voltaic current between the points.
E-lec′tro-scope.
An instrument for detecting electrical excitation.
It is shown at
c,
Fig. 1853, and consists of a glass jar with a wooden bottom, a brass wire passing through the cork and surmounted by a ball of the same metal; to the lower end of the wire are gummed two depending strips of gold-leaf.
The test of the electric condition of a body is to bring a small ball suspended from a filament of silk against the body, and then apply the same ball to the knob of the electroscope.
The presence of electricity will be shown by the divergence of the leaves, which, being similarly electrified, will repulse each other.
A rod of glass or of sealing-wax rubbed and applied to the knob will determine whether the previous excitation was positive or negative.
The dry-pile electroscope consisted of a gold-leaf suspended between two balls, and
Grove improved on this by insulating the gold-leaf between two surfaces and charging it at the same time by an electrified rod. See electrometer.
E-lec′tro-tint.
A mode of engraving in which the design is drawn on a copper plate with an acidresisting varnish.
By the electro-bath a reverse is obtained, and from this copies are printed.
The process may be adapted to relief or to plate printing.
E-lec′tro-type.
A copy, usually in copper, of a form of type.
An electrotype is superior to a stereotype, as copper is harder and more durable than type-metal, and the plates take less room in storage.
A page of the type is covered with wax, which is driven into the interstices by powerful pressure.
The face of the wax-mold is covered with plumbago to give it a metallic surface to which the metal will adhere.
The positive pole of a battery is attached to the mold, and the negative to a copper plate, and both are plunged in a bath of sulphate of copper in solution.
The copper is deposited on the face of the mold in a thin film, which increases in thickness as the process continues.
The
shell having attained the thickness of a stout sheet of paper, the mold is removed from the bath, the shell detached, and strengthened by a backing of type-metal.
This process is called
backing-up. As type-metal will not readily adhere to copper, the back of the shell is coated with tin, and the
shell is then placed face downward on a plate, by which it is suspended over a bath of molten type-metal.
When it has attained the requisite heat, a quantity of the metal is dipped up and floated over the back of the shell.
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When cold, the plate is reduced to an even thickness by a
planing-machine.
For printing, it is mounted on a wooden backing.
Another mode of obtaining electrotype plates from a letter-press form is by a mold of gutta-percha, brushed with graphite and immersed in the electroplating bath.
Gutta-percha is also used for obtaining intaglio molds and then cameo impressions from woodcuts, for printing.
See electro-plating.
E-lec′tro—typo-graph′ic ma-chine′.
An apparatus invented by
Fontaine, a French barrister, for printing short legal documents, etc.
The letters of the alphabet—caps, lower-case, figures, etc.—are arranged around two horizontal disks, one above the other, and surmounted by a third disk which has notches corresponding to the types below.
A bar in the center is caused to press upon the notch representing any particular letter, which is, by electro-magnetic action, caused to drop and leave its impression on a sheet of paper wound upon a roller beneath, and then return to its place.
When the whole has been printed, letter by letter, in this way, an impression is transferred to a lithographic stone, from which any number of copies may be printed.
E-lec′trum.
1. Argentiferous gold: an alloy of
gold and
silver.
A vase and eight drinking-cups of this material were found in an ancient Scythian tomb at Kertch.
2. An alloy of copper, zinc, and nickel: Germansilver.
See alloy.
El′e-phant.
A size of drawing-paper measuring 28 × 23 inches, and weighing 72 pounds to the ream.
A flat writing-paper of about the same dimensions.
El′e-vated Bat′ter-y.
One which has its whole parapet elevated above the natural surface of the ground; to procure the mass of earth required, a ditch is usually dug directly in front of the parapet.
El′e-vated Ov′en.
One whose baking-chamber is situated above that plate of the stove in which are the holes for the pots and kettles.
El′e-vated Rail′way.
A railway with an elevated track.
Any railroad supported on a continuous viaduct may be said to be an elevated railway, but the term has lately received a rather more limited application.
It is now particularly applied to city railroads whose track is so elevated as not to materially infringe upon the street area, already too limited for the convenience of the citizens and the traffic.
The necessities for more convenient transportation of passengers in New York City, especially on
Broadway, have perhaps given the greatest stimulus to invention in this line, and the question of elevated railway
versus subterranean railway has been very thoroughly debated.
The capitals and other large cities of the world were not originally laid out for the modern means of locomotion.
We see in the cities of
Asia the condition which formerly existed in
European towns, — narrow streets without sidewalks, adapted for pedestrians, equestrians, pack-animals, and sedanchairs.
Jeddo, Macao, and other Asiatic cities where the natives are yet dominant, have in general no provision for wheeled vehicles, and
London before the great fire of 1666 was in much the same condition.
The foot-traveler was jostled by the horseman, and stood on one side to let the train of packanimals go by, just as the modern traveler resigns the road in favor of the loaded camel or the ambling donkey in the streets of
Alexandria.
The sedanchair of
England and the palanquin of
Constantinople were carried by shambling porters, who were attended after nightfall by torch-bearers and guards, who illuminated the way and kept off the prowling robber.
Asia, having stood still, preserves the institutions to which we have alluded;
Western Europe and the
West have outgrown them some time since.
The topography of old
Boston and Dutch New York show that no ideas of these modern stirring times troubled the engineers and architects of those days, and it has become a problem with their successors how best to adapt the thing as they find it to modern needs.
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Elevated railways. |
London has solved the problem by brick viaducts and subterranean railways, which are successful and safe; of the latter it may be added, profitable.
New York, of all our American cities, is most interested in obtaining the best solution of the problem.
The viaduct of the
London and Greenwich Railway is 3 miles and 60 chains in length; being composed of over 1,000 yellow brick arches, 18 feet span, 22 feet high, 25 feet wide.
It cost over $1,300,000 per mile, and has not proved a paying investment to the shareholders.
The
London and Blackwall Railway is upon a
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continuous viaduct of brick arches, and is 3 miles 38 chains in length.
It cost pound1,083,951.
The public are benefited more than those who built it.
These are two examples of elevated railways of a certain kind.
The Greenwich Railway was always worked by locomotives.
The Blackwall Railway was for many years worked by stationary engines and wire ropes.
In 1821,
Palmer, engineer to the
London Dock Company, patented a railway whose single track was elevated upon pillars, which were of such lengths as to bring the track to a level or moderate inclination, notwithstanding the inequalities in the surface of the ground.
This is shown in the upper illustrations of
Fig. 1856. The boxes
H are in pairs, suspended on each side of the carriage, which travels upon a pair of grooved wheels
D. The track
K is supported on the pillars.
The wheels are placed one before the other, and the axles are extended laterally so as to support the boxes by the suspension-rods
I. The center of gravity of the loaded boxes is below the level of the rail.
The carriages are hooked together, and are drawn by horses and a towing-rope.
A railway on this principle was constructed in 1825 at
Cheshunt, in England, and used for conveying bricks across the marshes to the river
Lea, where they were shipped.
Fisher's English patent, 1825, in the same figure, shows a suspended carriage between two lines of rail.
In the figure, the bar
a with rail-flanges
b b is shown suspended by rods from a catenary chain, which is supposed to be spanning a river or deep gulley.
The carriage
f has two pairs of wheels which traverse upon the flanges
b b, and support the bar
h from which is suspended the freight.
One of the views shows a modification, in which the rails are flanges of a hollow box or trunk
c, the lower side of the box having a continuous longitudinal slit, allowing the passage of the suspension-bar.
The mode of propulsion is probably by a wire or rope.
Dick's elevated railway (English patent, 1825) had a double track supported on vertical pillars
m m of varying hight when crossing irregular surfaces, so as to preserve a level, or nearly so.
The track has two rails, upon which the wheels
n of the carriage traverse; and beneath the rails are safety-wheels on the sides of the carriage, which keep the upper wheels from leaving, should the carriage sway and jump with high speeds.
The mode of propulsion was to be by drag-ropes from stationary engines.
The lower wheels journaled between the sections of the supporting frame are for the ropes to run in.
Warren and
Blume's elevated railway
M is on the principle of the Fisher (
English) patent of 1825.
The rails are supported upon inward projections at the spring of an arch
s, which is attached by one end to a single post
t. A truck runs on this track, and the car is suspended from the truck, and is drawn by horses.
The truck wheels have brakes which are operated from the car.
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Arcade Railway. |
Fig. 1857 shows another form which is supported on columns and reached from the second floors of houses.
It is driven by dummy-engine, compressed air, or by rope.
Another form is proposed to span the street and form an arcade. (
Fig. 1858.)
Cheseborough's elevated railway consists of a series of inclined planes down which a car runs by its own gravity, elevating platforms being interposed to raise the car from the foot of one incline to the head of the next.
The platforms are elevated by a perpendicular lift operated by compressed air.
In
India,
Australia, and some other places, it has not been unusual to cross gullies and rivers by means of a bucket or basket suspended from a cord.
The patents of
Palmer,
Fisher, and
Dick, already cited, are an amplification of this idea, a carriage being arranged to travel on a rail.
The idea has recently been reduced to practice in a compact and useful form.
See wire-way.
El′e-vating—block.
A tackle-block used in elevating hay or bales, where, after the object has been raised to a given hight, the block is required to travel along to a position above where the load is to be deposited.
The track-rope passes through the case under the
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locomotive pulleys.
The draftrope leading from the hay-fork to the team passes between the lower pulley and the stop.
The cord running over the pulley in the rear operates the stop that rigidly connecting the draft to the track-rope above arrests its progress in either direction.
It is managed by a depending checkrope, which is grasped by a man on the barn or warehouse floor.
 |
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Elevating-block. |
El′e-vating—clutch.
Designed to attach a clutch to an elevated beam in a barn, as a means of suspension of the tackle of a horse hay-fork, and to detach the clutch therefrom when required.
It has two arms attached to a handle of any suitable length, and arranged to engage the jaws of the clutch to hold them open until the beam is grasped or to unclose them when required.
 |
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Elevating-clutch. |
El′e-vating-screw.
One beneath the breech of a piece of ordnance, to give the elevation or vertical direction to the piece.
In fieldpieces it is bedded in the stock immediately under the basering of the gun, which rests on the top of the screw.
The latter is turned by four handles.
In theodolites and other geodetical and astronomical instruments a similar contrivance is used for leveling the instrument.
See also jack-screw, etc. See list under hoisting.
Ele-va′tion.
1. (
Astronomical Instruments.) The arc of a vertical circle intercepted between an object and the horizon.
2. (
Dialing.) The angle of the gnomon with its base.
3. (
Gunnery.) The angle of the line of fire with the plane of the horizon.
4. (
Drawing.) A side or end view of an object or representation on a perpendicular plane.
An end or side view of a building or machine drawn according to the actual width and hight of its parts without reference to perspective.
Projections or depressions from the plane of the general surface are indicated by shadows equal in width to the depth of the elevation or depression, the light being supposed to fall at an angle of 45° both to the vertical and horizontal lines of the drawing, and usually from the upper and left-hand side.
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Elevation:— porch and Veranda (rural Gothic). |
El′e-vator.
1. A machine for transferring grain by raising it from the car, a bin, or the hold of a ship, to an elevated hopper, whence it is discharged by any one of a series of spouts directed to a bin for storage or to the hold of a boat, a car, or to a run of stones.
Elevators are used in flour-mills to carry the wheat to the upper story, where it is cleaned in the smut-mill; also to raise wheat, so cleaned, to a bin whence it proceeds to the stones; also to raise the meal to the bolt, the offal to the bran-duster, etc., as the case may be.
Elevators are also used in many other machines for raising small objects or materials, such as the tailings in a thrashing-machine or clover-huller.
These may be consulted where they occur under these heads.
They are also used in elevating bricks, mortar, etc., in building.
See list under Hoistingmachines.
 |
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Grain-elevator. |
2. A platform or cage in a warehouse, hotel, mine,
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or elsewhere, for raising or lowering persons, goods, or material to or from different floors or levels.
See hoist; man-engine; cage. Also the list above cited.
3. A building specially constructed for elevating, storing, and loading grain into cars or vessels.
These structures are very capacious both as to the capacity for handling and storing, but the construction is very simple.
An
elevator-leg, so called, seen in
Fig. 1863 and also in
Fig. 1862, reaches into the bin or cellar into which the contents of the wagons or cars are discharged.
A strong belt, carrying a series of buckets, travels over a drum at the lower end and also over one at the upper end, where the buckets tip over and discharge into the upper bin. This, as seen in Fig. 1862, has valved spouts
F which direct the contents into either one of the deep bins
A. The floors of these bins are over the tracks, and valves in the floor allow the contents of the bins to be discharged into cars or canal-boats, which are brought beneath.
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Elevator-leg. |
In unloading from ships, the leg is a pivoted, adjustable piece, which is first raised to obtain the necessary hight, brought over the hatchway, and lowered thereinto.
In practice, the grain is discharged into the hopper of a weighing-machine gaged exactly for one hundred bushels; by pulling on a valve the contents are sent by a spout to the bin, the valve closed, the elevating resumed, and so on. Seven thousand bushels an hour are thus weighed.
An elevator at
Milwaukee is 280 feet long and 80 feet wide.
The total length of the great driving-belt, urged by a 200-horse-power engine, is 280 feet, that is, the half extending from cellar to comb is 140 feet, and the down half is of course equal to it. This belt is 36 inches wide and 3/4 of an inch thick, and is made of six-ply or thicknesses of canvas, with sheets of india-rubber passed between and into them.
It drives nine receiving elevators or belts set with buckets, each of which lifts the grain 140 feet. The buckets are made of thick tin, bound with hoop-iron, and are well riveted to the belt at intervals of fourteen inches; six inches across the mouth and eighteen inches long.
When full, one contains a peck.
They do not usually go up quite full, but, allowing for this, there are 100 pecks = 25 bushels, loaded on one side of one of these belts whenever it is at work.
If all nine are running at once, as is often the case, the quantity of wheat lifted on these swift-running belts is 225 bushels.
The established weight of a bushel of No. 2 Milwaukee Spring is 55 pounds. This would make the total lift of the receiving elevators during the time they are at work over 12,000 pounds.
The bins in which this wheat is poured are of great size, being 60 feet deep, 20 wide, and 10 across, containing 12,000 cubic feet.
The total receiving and storing capacity of this building is 1,500,000 bushels.
Of the crop of 1869 it received 7,000,000 bushels.
About 10,000 bushels are taken into a train of the average length; so 2,100 trains were that year rolled into this elevator and discharged.
In discharging on to the
Lake grain-vessels, as soon as a ship is anchored beside an elevator the hatches are removed and great spouts extend over them from the bottom of one of the bins described.
The gate is raised, and a torrent of wheat pours down.
The loading power of these spouts is 12,000 bushels an hour.
A vessel with a capacity for 18,000 bushels may be loaded in an hour and a half.
The
Oswego and
Ogdensburg schooners and vessels destined for the
Welland Canal usually take on from 12,000 to 20,000 bushels.
The
Buffalo vessels are larger, often receiving 30,000, and in a few cases 45,000 bushels.
4. (
Surgical.) An instrument employed in raising portions of bone which have been depressed, or for raising and detaching the portion of bone separated by the crown of the trepan.
The common elevator is a mere lever, the end of which is somewhat bent and rough, in order that it may less readily slip away from the portion of bone to be raised.
The elevator of
Louis has a screw peg united to the bridge by a kind of pivot.
Pettit's elevator is a straight lever, except at the very point, where it is slightly curved.
The triploid elevator consists of three branches united in one common trunk.
The elevator is one of the instruments of the trephine case.
A curved instrument for operating upon depressed portions of the skull was disinterred at
Pompeii, 1819, by
Dr. Cavenke of
St. Petersburg.
El′e-vator—buck′et.
One of the grain-cups on the traveling belt of the elevator.
El′io-type.
（
Photography.) A mode of multiplying photographic copies of artists' work, patented by
Eliot,
England.
The painting is made upon glass in a body-color more or less dense, and consequently more or less effective as a negative, and from it positives are printed.
Eli—qua′tion.
The process of separating metals by exposure in a furnace or on a hearth to a heat which melts one and does not melt the other.
See liquation-furnace.
El-lip′so-graph.
An instrument for describing ellipses.
The pins of the beam traverse in the slots of the trammel, each occupying its own slot, and the pencil at the end, as the beam revolves, is guided in an elliptical path.
See trammel.
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Ellipsograph. |
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Elliptical wheels. |
There are many varieties of compass for this purpose.
El-lip′ tical—arch.
（
Architecture.) An arch having two foci and an elliptical contour.
The arches of
London Bridge are the finest elliptical arches in the world: the middle one has 152 feet span.
El-lip′ti-cal—gear′ing.
See elliptical-wheel.
El-lip′ti-cal—wheel.
One used where a rotary
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motion of varying speed is required, and the variation of speed is determined by the relation between the lengths of the major and minor axes of the ellipses.
In the upper figure, variable rotary motion is produced by uniform rotary motion.
The small spur pinion works in a slot cut in the bar, which turns loosely upon the shaft of the elliptical gear.
The pinion is kept to its engagement by a spring on the shaft.
The slot in the bar allows for the variation of length of radius of the elliptical gear.
El-lip′tic—chuck.
A chuck invented by Abraham Sharp, for oval or elliptic turning.
See chuck.
El-lip′tic—spring.
（
Vehicle.) One formed of a number of bent plates in two sets, curved apart in the middle and united at the ends.
The pressure is brought upon the middle and tends to collapse them.
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Elliptic carriage-spring. |
In the illustrations, the spring is of one or two pieces, united by blocks or bolts.
E-lutri-a′tion.
Purification by washing, when the water carries off a lighter or more soluble material from the heavier portion, which is designed to be saved.
It differs from
lixiviation in the latter respect.
To recover saccharine matter from animal charcoal, the latter may be
lixiviated, water being passed through the mass to carry off the sugar.
To remove saccharine and coloring matters from starch in the process of manufacture, the material is
elutriated, and the granules of starch settle in the bottom of the vat; the substances remaining in solution are removed by decantation.
El-y-dor′ic Paint′ing.
A mode of painting invented by
Vincent, of
Montpelier, intended to combine the fresh appearance of water-colors and the mellowness of oil-painting.
The vehicle for the pigments is an emulsion of oil and water with the intervention of a gum or mucilage.
Em.
（
Printing.) The square of the body of a type.
As the “m” in early fonts had a square body, it became a unit of measure for compositors' work.
E-mail′—om′brant.
A process which consists in flooding colored but transparent glasses over designs stamped in the body of earthenware or porcelain.
A plane surface is thus produced, in which the cavities of the stamped design appear as shadows of various depths, the parts in highest relief coming nearest to the surface of the glass, and thus having the effect of the lights of the picture.
Introduced by the
Baron A. de Tremblay, of Melun.
Em-balm′ing.
The art of preserving the dead bodies of men or animals.
The earliest examples are found in
Egypt, where it was practiced over 3000 years ago. There the custom was universal and intimately connected with their religion, as they believed in the resurrection of the body, and imagined that after the lapse of 3000 years the spirit would again inhabit its original tenement if the latter was still in existence.
The invention was ascribed by them to
Anubis the son of
Osiris, who was said to have performed the office for his father.
It has been estimated that more than 420,000,000 mummies were embalmed between his time and the year 700 A. D., when the practice fell into disuse, besides an innumerable multitude of sacred animals, as dogs, cats, apes, ibises, bulls, rams, foxes, crocodiles, serpents, etc., which are found along with human mummies in the tombs.
The
Egyptians, however, were not the only people who embalmed their dead.
The practice prevailed, though not so extensively, among the nations of
Asia, and was, at a somewhat later period, in use to some extent among the Greeks and Romans.
Herodotus gives a long description of the different methods employed by the ancient
Egyptians.
These varied according to the rank or wealth of the subject.
Drying the bodies in sand was a method chiefly practiced among the poorer classes; and it may be remarked that, in a warm dry climate like that of
Egypt, decomposition does not take place so readily or speedily as in those which are favored with more moisture.
Embalming was also performed by salting in natron and then drying; boiling in resins and bitumen; and by removing the brain and viscera, washing with palm wine, and then applying fine resins, myrrh, cassia, and other aromatic substances.
In some cases oil of cedar was injected into the cavity of the body, which was then steeped in a solution of natron for 70 days, when the viscera came away, leaving little but skin and bone remaining.
Among the upper classes, the bodies, after being prepared, were swathed in linen bandages saturated with gum, the total length of which amounted in some instances to more than 1,000 yards.
The physicians embalmed Israel (
Gen. 1. 2) B. C. 1689, and the bodies of the Hebrew kings were embalmed with spices.
Within and about the bodies of different mummies have been found sulphate of soda, saltpeter, common salt, soda, oil of cedar, turpentine, asphalt, myrrh, cinnamon, and other substances.
The opinion has been advanced that an essential part of the process was the application of heat to the bodies, which were filled with some bituminous substance, by which means creosote was generated.
As all mummy bandages were smeared with gum, and bear the appearance of having been heated, being often reduced to tinder, the production of creosote may have been the object for which they were gummed and partially calcined.
The cost of the most expensive method of embalming was a talent of silver, more than $1,100; according to Calmet, the prices ranged from the neighborhood of $300 to $1,500.
The principal materials used by the ancients (the Egyptians excepted) in embalming were honey, brine, wax, and vinegar.
Pharnaces put the body of his father,
Mithridates, in brine, in order to preserve it during its transportation to Pompey.
Several curious monsters and an ape were pickled and sent to
Rome; Pliny and St. Jerome mention them.
The body of St. Guibert was pickled to make it keep during a long journey in summer, A. D. 1113.
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The bodies of several Grecian kings were preserved in honey.
Agesipolis, who died in Macedonia, was thus sent home to
Sparta.
Alexander is said to have been sent to
Egypt in honey; by others, to have been embalmed in
Egyptian style.
Perhaps he went to
Alexandria in honey, and was then embalmed in regular order.
The Emperor Julian II.
was placed in honey mixed with spices.
Wax and waxen cerecloth were used for centuries in
England.
The body of one of the
Edwards, interred 1307 and exhumed 1774, was preserved in natural shape, but fragile.
The body of Lord Nelson was sent to
England in a puncheon of rum. The sailors ran foul of the cask, and, getting drunk, playfully called it “tapping the admiral.”
The poor man was nearly dry by the time he reached home.
The
Scythians, Assyrians, and Persians used wax. The body of
Agesilaus was covered with wax, but the practice soon became general of wrapping in waxed cloths.
We read of these cerements in the preparation for burial of Philip of Burgundy, 1404; Edward I. of
England, 1307; and George II.
The cerecloth and aromatics for the latter cost pound152.
John Hunter (died 1793) embalmed several bodies by injection into the arteries and veins.
The bodies are preserved in the Museum of the
College of Surgeons,
London.
The
Khasias, a people of the Himalayas, preserve the bodies of their dead in honey till the cessation of the periodical rains permits their being burned.
The quantity of rain which falls in that region is remarkable.
See rain-gage.
Embalming was practiced by the Guanches, or aboriginal inhabitants of the
Canary Islands, and by the ancient
Peruvians.
Mummies from the latter source are now to be seen in the museum of the Smithsonian Institution.
Some bodies have been preserved for ages by burial in caverns, the earthen floors of which contained a notable quantity of saltpeter.
The steepes of Tartary, some of the uplands of
Montana and
Colorado, and the dry uplands of the Andes, are nitrous.
Many caves are so also, the
Mammoth Cave of
Kentucky, for instance.
In very recent times, with the increase of chemical knowledge, considerable attention has been devoted to the subject, and various processes and compounds have been devised.
Dr. Chausier employed a solution of corrosive sublimate, with which the corpse, previously disembowelled and cleansed, is saturated; this imparts firmness to the flesh and renders it imputrescent.
Gaural practiced injecting the veins with sulphate of alumina.
Dr. Ure proposes chloride of mercury and wood vinegar to be used in a similar way.
M. Falconi found that sulphate of zinc, injected into a body, would preserve it in a flexible condition for some six weeks, after which it began to dry up, though still preserving its natural color.
Chloride of zinc and sulphate of soda are also sometimes used.
A more simple form of preparation for injection, well suited for anatomical purposes, consists of glycerine, 14 parts; soft sugar, 2 parts; nitrate of potash, 1 part.
It is found that, after saturation for some days in this solution, the parts become comparatively indestructible, and change neither in size nor figure.
Dr. Hutton's (1863) composition is 4 pounds of zinc dissolved in 6 pounds muriatic acid, to which are added 1 gallon alcohol, 2 drams arsenic, and 1 dram corrosive sublimate; the fluid is injected into the arteries in a heated state.
Dr. Morgan's (
English, 1864) is 6 pounds common salt, 1 1/2 pounds nitrate potash, 1 1/2 pounds powdered alum, and 2 drams to 1 ounce arseniate of potash.
This, in the form of a solution, is injected into the heart.
This process embraces some peculiarities in the mode of treatment of the subject and manner of injecting the fluid.
Coffman's (1867). Distilled water, 1 gallon; carbolic acid, 4 ounces; nitrate of potash, 4 ounces; alcohol, 4 ounces.
Brunetti, of
Italy (1867), expels the blood from the tissues by injections of pure water and of alcohol, and fatty matters by injections of sulphuric ether, and afterwards injects a solution of tannin into the arteries, veins, or excretory canals, after which the body is dried in a case heated by steam to a temperature of 90° centigrade.
E
de la Granja (1867) employs a solution of sulphurous acid and the sulphides of soda, potash, or lime, in water or alcohol, injected into the aorta.
The cavities of the body, head, thorax, and abdomen are filled with tannin, gun-cotton, camphor, and resin dissolved in absolute alcohol or ether, and stiffened with cotton and wax.
Em-bank′ment.
A structure raised to prevent water from overflowing a level tract of country, or to support a roadway.
Technically, in civil engineering, the earth removed to produce a level is excavation, and that which requires to be heaped up for the same purpose is embankment.
A raised mound or bank of earth to form a barrier against the encroachments of the sea. See dike.
Or against the overflow of a river.
See levee.
Or to carry a railroad, canal, or road across a tract of low ground or across a ravine or gully.
See filling.
The oldest embankment in
England is
Roman, that of
Romney Marsh.
In the time of Crornwell, 425,000 acres of fen and morasses were recovered, 1649-51.
The embankment by which the
Nile was turned from its course before the time of Abraham is mentioned under dike (which see). Reference is also there made to some of the works of
Holland.
The bottom part of the embankment of the Amsterdam and Haarlem Railways through the low country consists of treble ranges of fascines, tied down by longitudinal poles 39 inches apart from center to center and 10 inches diameter, two double stakes at each end of the poles, and two ties in the intermediate distances.
The interstices of the fascines and the space between the rows are filled in with sand.
The upper part, forming the encasement for the ballast, is made of three rows of treble fascines, well staked, and wattled together.
A core of sand or clay, faced with step fascines, is made up to low-water mark.
Upon this a bed of rushes, fastened down by stakes and wattles, is laid; and the upper portion of the bank is faced with fascines of a regular slope of 1 to 1.
See also
Wiggins's “Embankments of lands from the sea” (
Weale's series).
Em-bat′tled.
（
Fortification.) Having a parapet with embrasures.
Em-bo′lus.
Something inserted in another and moving therein, as a wedge, a piston of a steamcylinder, the bucket or plunger of a pump.
Em-bossed′ Pa′per.
Paper having an ornamented surface of raised work; done by stamping or rolling.
Embossed paper or cards may be copied in metal by taking a mold in wax, treating the surface with graphite, and subjecting it to electro-deposition in a bath of solution of sulphate of copper.
Em-bossed′ Print′ing.
Printing in which the paper is forced into dies, into which the letters have
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been cut or punched.
The result is raised letters, used for printing for the blind, and various kinds of ornamental work.
Embossed typography is also effected by pressing the type into the paper, raising the letters or characters on the other side.
See printing for the blind.
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Embossing-type. |
Em-boss′ing.
Ornamenting by raised work or figures in relief.
It is applied to many objects.
Stamps or initials are embossed on envelopes, paper, cards, etc.
Ornaments are embossed on book-covers, especially on those of cloth.
Leather is embossed for binding and many ornamental uses, saddles,
porte-monnaies,
pocket-books, satchels, etc.
Textile fabrics are embossed for various purposes.
Glass is embossed — so called — by molding with raised figures.
Em-boss′ing—i′ron.
（
Sculpture.) A tool for giving a peculiar grained or caruncular appearance to a marble surface.
Em-boss′ing–ma-chine′.
A machine in which a compressible material is placed between a rolling or reciprocating surface and a bed, the moving portion having a design in intaglio, which confers a cameo ornamentation upon the object.
In
Fig. 1868 the roller has a roughened surface and is rotated by a hand-crank.
Above the roller is a hollow pressblock having a removable convex-faced plate, with ridges for embossing any substance passed between it and the roller.
The block is depressed by a pivoted lever having an elastic press-band over the end. The hollow within the block serves to introduce some substance to heat the embossing-plate.
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Embossing-machine. |
The embossing-machine for giving an indented ornamentation to velvet and other goods (
Fig. 1869) has engraved copper rollers, which are heated by inclosed red-hot irons when operating on dampened goods, as in giving a “watered” surface.
Em-boss′ing—press.
A hand-stamp or machine for giving a raised surface to an object placed between the descending die and the bed. In the example, the lever is raised by a spring, and is driven down by a blow of the hand, impressing the paper placed between the intaglio upper die and the cameo counter die.
Embossing-presses of bookbinders are screw, toggle, or lever presses, according to the area of surface and character of material under treatment, and other considerations.
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Embossing-machine. |
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|
Embossing-press. |
Em-boss′ing wood.
A process of indenting designs in wood by heat and pressure.
The wood is saturated with water, and the castiron mold heated to redness and pressed forcibly upon the wood.
The water preserves the wood from ignition, though the surface is slightly charred.
The iron is reheated, the wood re-wetted, and the branding-iron again applied.
This is repeated until the wood fills the mold.
The surface is cleansed between each operation, and finally with a scratch-brush, and any desired color may be retained or obtained by the extent to which the charcoal and discolored surface are removed.
Perforated designs are obtained by pressure upon portions of the surface and the removal of a scale of material by a saw. See carving.
Em-bra′sure.
1. (
Fortification.) A crenelle opening cut through a parapet or wall to fire guns through.
The
cheeks are the sides.
The
mouth is the widest or outer part.
The
neck is the narrow part.
The
sole is the bottom part.
The
sill is the front of the
sole.
The
merlon is the part of the parapet between two
embrasures.
Embrasures are usually perpendicular to the par-
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apet, but are sometimes inclined thereto so as to obtain a line of fire in a particular direction.
2. The inward enlargement of the cheeks or jambs of a window or door.
Em-broid′er-ing—ma-chine′.
A form of
sewing-machine in which the cloth is moved beneath the reciprocating needle-bar according to the requirements of the tracing, while the needles and hooks retain their respective relative positions above and below the fabric.
Heilmann's embroidery-machine (Mulhausen) has an arrangement by which the needles — 100, more or less — are attached to a carriage which travels to and fro in front of a vertical web. The needles have an eye in the middle and a point at each end. They are grasped by pincers and pulled through.
Em-broid′er-y.
Ornamentation by raised figures of needle-work.
This is a very ancient art.
The
Egyptians, Babylonians, Medes, and Persians all excelled in it.
The adornments of the tabernacle in the wilderness were of tapestry worked in blue, scarlet, and gold.
The garment of Sisera, as referred to by
Deborah, was embroidery, “needle-work on both sides.”
See damask.
Homer refers to embroidery as the occupation of
Helen and
Andromache.
The tents of wealthy Arabs have an inner covering of white embroidered stuff beneath the dark, outer, water-proof covering of goat's-hair.
“The Tartar women excel in embroidery, and exhibit in this a skill, taste, and variety that is really admirable.
It is very doubtful whether it would be possible to find, even in
France, embroideries as beautiful and perfect as those sometimes executed by Tartar women.” — Abbe Huc's
Travels in Tartary.
The tent of a late Persian shah was a load for forty camels, and cost $10,000,--000.
It was embroidered with gold, studded with precious stones and pearls; the figures representing animals, vegetables, and the works of men.
The
Chinese, at the present day, are skillful and patient workers at this art, and excel in the disposition of colors.
The North American Indians have a certain rich and barbaric taste in the disposition of colors (preferably scarlet); with the addition of beads, porcupine quills stained, and other mere bizarre ornaments, such as skins, claws, and feathers of birds, claws of bears, ears of the lynx and fox, tails of
Mustelidoe, shells, etc.
Embroidery is generally done in frames, the woven fabric being stretched flat and the needle passed through and through.
Em′e-rald.
A type, used in
England, between nonpareil and minion.
Nonpareil.
Emerald.
Minion.
Em′e-ril.
A glazier's diamond.
A
quarrel, or
quarry.
Em′e-ry.
An amorphous, compact, opaque variety of corundum, consisting chiefly of indurated alumina.
It is extremely hard and cuts almost all minerals, and is extensively used in cutting and polishing glass and other hard substances.
The emery is stamped to powder and sorted into finenesses by bolting through sieves of different degrees of fineness.
For delicate purposes, it is sorted by elutriation.
It is made up into various forms with gums, resin, glue, clay, etc., according to purpose.
Emery-cakes are used to dress the edges of buffs and glaze-wheels.
They are formed of emery melted with bees-wax and made into cakes.
Emery-cloth is prepared by brushing the surface of thin cotton cloth with liquid glue, and sifting the emery-powder over the surface while still warm.
Emery-paper is made in the same way as emerycloth.
Emery-sticks and rifles are pieces of wood prepared in the same manner.
Emery-stones are made or formed of emery of the requisite coarseness, mixed with about half its weight of clay and water, to make a stiff paste, which is forced into a metallic mold by powerful pressure.
They are then dried in a muffle.
Disks, laps, and wheels are thus made.
Other cementing materials are frequently used instead of loam.
See grinding materials; also list under grinding and polishing.
Em′e-ry—grind′er.
An emery-wheel mounted in a stand, to be used as a grindstone.
It may be considered as such, indeed, the mineral corundum with a matrix of gum, resin, glue, vulcanite, etc.
The example is a double machine having two grinding-wheels and rests; one wheel being at one end and one at the other end of the mandrel, and both outside of the supporting frame.
The faces or edges of the wheels may be used.
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Emery-grinder. |
Em′e-ry—pa′per.
Paper brushed with liquid glue and dusted with emery of the required grade of fineness.
Em′e-ry Vul′can-ite—wheel.
A compound of emery and caoutchouc, molded into the shape of a grindstone or lap, and vulcanized.
Em′e-ry—wheel.
This is a leaden wheel in which emery is imbedded by pressure, or more commonly a wooden wheel covered with leather and with a surface of emery.
The wheel is fastened to a mandrel and rotated by a wheel and band; its principal use is in grinding and polishing metallic articles,
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especially cutlery.
Those wheels in which the edges are used are grinders, buff-wheels, cloth-wheels, glazers, etc. When the flat surface of the disk is used, they are known as
laps. The wheels may have coarse or fine cutting surfaces for different descriptions of work.
For polishing, flour of emery, crocus, or rouge may be substituted.
In machine-shops the emery-wheel is known as a
buff-wheel; among cutlers it is a
glazer.
Sometimes called a “corundum” wheel, from the specific name of the crystalline alumina used thereon.
The hardest known substance next to the diamond.
Emery is a dark, granular variety; the sapphire and ruby are peculiarly colored varieties.
E-met′ic—cup.
A cup of metallic antimony in which wine is left for ten or twelve hours to become emetic.
Em-is-sa′ri-um.
A sluice or flood-gate.
E-mol′li-o-type.
（
Photography.) A collodiochloride picture on opal glass.
Em-plec′tum.
A kind of masonry having a squared stone face; in the Greek it is represented as solid throughout, and in the
Roman having a filling of rubble.
One form of
Roman emplectum has courses of tiles at intervals.
See masonry.
Em′press—cloth.
（
Fabric.) A lady's
dress-goods, all wool and not twilled.
It may be considered as an equivalent to the merino, excepting the twill of the latter.
En-am′el.
A vitreous, opaque, colored material, tractable in the fire, and used in ornamenting metals; in painting on metals, to be subsequently fired.
Enameled bricks of various colors,
blue,
red, yellow,
white, and
black, are abundant in some of the mounds of
Babylon and other cities in Mesopotamia. — Layard.
Enameled pottery has also been recovered at
Thebes.
Vestiges of the
Roman occupation of Britain are occasionally disinterred in various parts of the country.
The art of painting in enamel or with metalline colors, and fixing them by fire, was practiced by the Egyptians and Etruscans on pottery, and passed from them to the Greeks and Romans.
Enameling was also practiced among the Chinese.
Specimens of enameled work are yet extant of early British,
Saxon, and
Norman manufacture.
An enameled jewel, made by order of Alfred the
Great, A. D. 887, was discovered in
Somersetshire, England, and is preserved at
Oxford.
An enameled gold cup was presented by King John to the corporation of
Lynn,
Norfolk, and is yet preserved.
Luca della Robbia, born about 1410, applied tin enamel to pottery, and excelled in the art.
Bernard Palissy, the Huguenot potter, born about 1500, devoted many years to the discovery and application of enamels of various colors to pottery.
He was remarkably successful in true copies of natural objects.
His method died with him. He died in 1589, in prison, for consciencea sake.
John Petitot, of
Geneva (1607 – 91), is regarded as one of the first to excel in portraits.
He worked for Charles I. of
England, and subsequently for Louis XIV.
of
France.
The revocation of the Edict of
Nantes drove him from
France to the city of his birth,
Geneva.
In 1632,
Jean Tontin, of Chateaudun, introduced the practice of grinding the colors in oil of spike, instead of water.
Faience and
majolica may be considered forms of the art.
The enameled portrait of herself, presented by Queen Victoria to
Mr. Peabody, is fresh in the recollection of those who speak the language common to the donor and presentee.
Enamel is applied to various kinds of pots and pans for stewing and preserving fruits whose flavor would be injured by contact with iron, and wholesomeness by being cooked in brass or copper.
The ordinary enamel for the purpose is common glass fused with oxide of lead.
This will not resist vinegar and some other acids, and a dangerous poison may be present unsuspected in the mess.
Articles exposed to the weather are sometimes enameled to preserve them from rusting.
This has been done with plowshares, mold-boards, waterwheels.
The asphaltum varnish which is burned on to some articles of hardware and household furnishing is not an enamel, but a bituminous varnish.
The term
enamel, as applied to these, is therefore a misnomer.
One of the most familiar examples of enameling is a watch-face.
The white ground of these is first fired, the figures being added afterwards.
The backs of gold watches and numerous articles of jewelry are enameled by first engraving them so as to make depressions to hold the pulverized enamel, which is burned in, and the whole polished down to a uniform surface.
Enameled work may be ground by the horizontal lapidary mill or lead-wheel, with emery; second, the same with rottenstone and water; third, polished by the leather lap or buff-wheel with putty powder.
Or the process may be completed in a lathe, using the same materials, and either chucking the object to be ground and polished, or placing it on a mandrel.
In hand polishing, the work is roughed down with slips of water-of-Ayr stone and water, followed by slips of wood dipped in powder of pumice-stone and crocus successively.
En-am′eled board.
Card-board treated with a surface of
white lead and size laid on by a large, flat brush and smoothed by a round badger's-hair brush.
A powder of talc (silicate of magnesia) is rubbed upon the dried surface of lead, and the face is then polished by the brush.
En-am′eled Leath′er.
A glazed leather for boots, shoes, carriage upholstery, and other purposes.
It is prepared from hides, which are split to the required thickness, well tanned, curried, and passed through two operations; the first to render the leather impermeable to the varnish, and the latter to lay on the varnish.
The hides used are those of kip, calf, ox, or horse.
They are rubbed on the grain or flesh side with three coatings of boiled
linseed oil mixed with ochre or ground chalk, and dried after each coating.
The surface is then pumiced, treated with the same material of a thinner quality in several applications.
Over the surface thus prepared are laid successive layers of boiled
linseed oil and of the oil mixed with lamp-black and turpentine spread on with a brush.
The surface, which has become black and shining, is then varnished with copal and
linseed oil with coloring matters.
The following is recommended.
| Boiled linseed oil | 20 pounds. |
| Turpentine | 20 pounds. |
| Thick copal varnish | 10 pounds. |
| Asphaltum, or | 1 pound. |
| Prussian blue, or | 1 pound. |
| Ivory black | 1 pound. |
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Five coats of varnish are successively applied, and the colors are varied at will.
En-am′eled Photo-graph.
（
Photography.) Metal or pottery is used for the ground; the image is developed by nitrate of silver until the half-tints are overdone or obscured, and the deep shades are covered with a thick deposit.
The heat of the muffle drives off the organic matters which formed but vehicles, and the fire cleans the image and restores the brilliancy and delicacy.
A thin layer of flux fixes the image.
See
Comptes Rendus, June 11, 1855. “Photographic News,” Vol.
XIV. p. 86.
En-ameled ware.
The enameling of hollowware is by a mixture of powdered glass, borax, and carbonate of soda, mixed, fused, cooled, and ground.
The ware is cleansed with acid, wetted with gumwater, the powder dusted on, and then fused by heat carefully applied.
En-amel-ing.
The art of applying vitrifiable colors to metal, pottery, or glass.
The colors are prepared from the oxides of different metals, melted with a vitreous flux and laid on with a fine brush; the medium being oil of spike or some other essential oil. The work is heated in a muffle, which fuses the colors so that they adhere to the metal or other object.
The principal colors are oxides of lead, platinum, chromium, uranium.
Oxides of tin and antimony give opacity.
The enameller works, not with actual colors, but with materials which will assume certain colors under the action of fire.
See enamel.
En-am′el-ing-furnace.
For vitrifying the enamel coating on a plate, glass, or biscuit.
The work is placed in a
muffle, which consists of an arched chamber in the midst of a small furnace, and surrounded by fuel, which keeps it at a red heat, although the fuel cannot touch the work.
The furnace and muffle are sometimes made of
sheet-iron mounted on legs so as to bring the work to the level of the artist's eye.
En-amel-ing-lamp.
（
Glass.) A glass-blower's lamp with blow-pipe for performing some of the more delicate surface ornamentation of glass.
En-amel-kiln.
（
Porcelain.) The enamel-kiln for firing porcelain which has been
bat-printed, that is,
printed on the glaze, is made of fired-clay slabs, and is 6 1/2 by 3 1/2 feet, and 7 1/2 feet high, with flues beneath and around.
The fireplaces are at the sides, and smoke and flame are excluded from the interior.
En-amel-painting.
Vitrifiable colors are laid on metal and fused to it. See enamel.
En-amel-paper.
Paper with a glazed metallic coating.
Various metallic pigments are employed, such as will spread smoothly and take a polish.
The pigments are
white lead, oxide of zinc, sulphate of barytes, china, clay, whiting, chalk, in a menstruum or upon a previous coating of glycerine, size, collodion, water, varnish, etc.; afterwards polished by an agate or between calendering or burnishing cylinders.
En-caustic.
A mode of painting in which the colors are laid on or fixed by heat.
The ancient
Greek encaustics were executed in wax-colors, which were burned in by a hot iron, and covered with a wax or encaustic varnish.
Pictures in this style were common in
Greece and
Rome.
(See
Smith's “Dictionary of
Greek and Roman Antiquities.” ) The credit to Gausias, of
Sicyon, 33 B. C., as the inventor, is rather to be taken as an indication that he was an improver.
Sir Joshua Reynolds, in his attempts to fix his colors durably, mixed wax with them as a vehicle.
On one occasion he placed his painting before a fire to mellow the tints by warming the wax. On returning, he found the lady's face had slipped down over her bosom.
The term “encaustic” at the present day is mostly confined to colors burnt in on vitreous or ceramic ware.
By the ancient method, according to Pliny, the colors were made up into crayons with wax, and, the subject being traced on the ground with a metallic point, the colors were melted on the picture as they were used.
A coating of melted wax was then evenly spread over all, and, when it was quite cold, was polished.
The art was revived by
Count Caylus in 1753.
The wood or canvas is coated with wax, which is warmed at the fire.
The colors are mixed with white wax and powdered mastic, which are rubbed smooth with gum-water and applied with a brush.
The surface is coated with white wax and polished.
En-caustic-brick.
Diodorus Siculus relates that the bricks of the walls of
Babylon, erected under the orders of
Semiramis, “had all sorts of living creatures portrayed in various colors upon the bricks before they were burnt.”
En-caus′tic-tile.
An ornamental tile having several colors.
A mold is prepared which has a raised device on its face so as to leave an impression in the face of the tile east therein.
This intaglio recess is then filled by a trowel with clay compounds, in the liquid or
slip state, and which retain or acquire the required colors in baking.
The tile is then scraped, smoothed, baked, and glazed.
This tile is common in ancient and modern structures.
The glazing came from the Arabs, who derived it from
India, and primarily from
China.
En-ceinte.
（
Fortification.) The line of circumvallation; the space inclosed within the ramparts of a fortification.
En-chased — work.
Chased work in
silver and
gold smithing.
See chasing.
En-chasing.
A form of engraving which results in an ornamental embossing.
It is partly executed by punching on the back and partly by the graver.
Another mode is by filling the object with pitch or lead, and then indenting from the outside.
The modes are variously combined, according to the object, the style, and the material.
See chasing.
End.
1. A sliver or carding.
2. (
Wearing.) One of the worsted yarns in a loom for weaving
Brussels carpet.
It proceeds from a bobbin on the frame and through a small brass eye called a
mail, by which it is lifted when its turn comes to be raised to form a loop in the pattern.
See Brussels carpet.
End′less-chain pro-peller.
One in which the paddles are attached to a traversing belt or sets of chains, which rolls over two parallel wheels.
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Endless-chain propeller. |
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End′less-saw.
A
band-saw, consisting of a steel ribbon serrated on one edge and passing continuously over wheels above and below the worktable.
Used for scroll-sawing, etc. See Bandsaw.
End′less-screw.
A screw whose action is continuous, engaging the teeth of a wheel which is revolved thereby.
It is used in graduating-machines, registers, odometers, and in many other places where a means of slow and positive rotation to a wheel is required.
A
worm-wheel.
There is a necessary relation between the pitch of the worms on the shaft and of the teeth on the wheel, and a revolution of the shaft moves the wheel a distance of one tooth.
By an index arrangement on the shaft to enable it to be turned a certain portion of a revolution, say through 6°, and having, say, sixty teeth in the wheel, the latter may be turned 1/3600 of a revolution at a time, a distance inappreciable to the eye. This is the
micrometer-screw. See micrometer.
 |
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Endless-screw. |
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|
Endosmometer. |
En-dos-mom′eter.
An instrument invented by
M. Dutrochet to measure the rapidity of endosmotic action; that is, the passage of a less dense fluid through a membrane which separates it from a denser fluid.
The
exosmose, or passage of the denser fluid in the opposite direction, is slower.
A simple form of the instrument is a trumpetshaped tube with a membrane covering its bell mouth.
The tube is filled with a solution of a given density and plunged in a solution of lesser or greater density to ascertain by successive trials the relative rapidity of the endosmotic or exosmotic actions, or the action of different fluids.
End-shake.
A certain freedom of endwise motion of a spindle or arbor, which has bearings at each end, so that the shoulders of the gudgeons or pivots (as in a watch) shall not bear against the journalboxes or plates.
End-stone.
One of the plates of a watch-jewel against which the pivot abuts.
See jewel.
Ene-ma-chair.
One specially constructed for the administration of clysters to the helpless and infirm.
En′e-ma-syr′inge.
A syringe for injection
per ano. See injection-syringe.
En-er′gi-o-type.
（
Photography.)
Mr. Hunt's process, called so by him from a supposed influence which he called
energia, as distinct from light (visible).
Enfield Ri′fle.
The British infantry servicearm prior to the introduction of the breech-loading system.
It was first extensively introduced in 1853, just prior to the
Crimean War. It has three shallow grooves, which make one turn in 6 feet 6 inches, the length of the barrel being 3 feet 3 inches, and the diameter of the bore .577 of an inch.
In construction and general appearance it very closely resembles the
Springfield rifle musket (caliber .58 of an inch) of the
United States service, with the exception that in the Enfield the barrel and other visible metallic parts are blued, while in the latter they are left bright.
Large numbers of these rifles have of late years been converted into breech-loaders on the Snider principle.
To these the term “
Snider Enfield” is applied.
See fire-arm.
En′fil-ade.
（
Fortification.) The act of obtaining a fire on a work in the direction of one of its faces.
Engine.
A machine which acts automatically, both as to power and operation.
Distinct from a
machine in its ordinary acceptation, whose motor is distinct from the operator, and a
tool, which is propelled and operated by one person.
En′gine-fur′nace.
A furnace appertaining to a steam-engine boiler.
En′gine-lathe.
A lathe of the larger kind, having a capacity for all the principal turning work of a machine-shop.
That shown in
Fig. 1875 has screw gearing, center and follow rests, and face-plates.
On the floor are shown the overhead counter-shaft and cone-pulley, a pile of change-wheels, and a face-plate.
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Engine-lathe. |
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En′gine-sized.
Paper sized by a machine, and not while in the pulp, in a tub.
En′gine-turning.
A system of ornamented turning done in a rose-engine lathe, and commonly seen on the outside of watch-cases.
Engi-scope.
A reflecting microscope, invented by
Amici, in which the image is viewed at a side aperture in the tube, in a manner similar to the Newtonian telescope.
Eng′lish.
（
Printing.) A size of type between
Great Primer and
Pica.
Great Primer, 51 ems to a foot.
English, 64 ems to a foot.
Pica, 71 ems to a foot.
En-graving.
Engraving is very ancient.
The oldest records are cut in stone, some in relief, some in intaglio.
The hieroglyphics of
Egypt are cut in the granite monoliths, and on the walls of the tombs and chambers.
In Exodus XXVIII.
we read that two onyx stones were to be engraved like a signet with the names of the tribes, 1491 B. C. The two kinds of stones of the high-priest's breastplate were engraved with the names of the tribes of
Israel.
Seals and signet-rings with the cartouches of the Pharaohs are in many museums; those of
London,
Berlin,
Paris, and the New York Historical Society, for instance.
The “graving with an iron pen and lead,” referred to by Job (chap.
XIX.), consisted probably of an etching or scratching process, that of a sharp stylus upon a piece of sheet-lead; Hesiod's poems were thus preserved.
The date is not quite determined at which this patriarch of Uz lived; but assuming him to be coeval with
Moses, we find quite an advanced state of the art in the time and country of the latter.
Moses was learned in all the wisdom of the Egyptians, and when the Israelites went out of
Egypt there were a number of skillful workmen able and willing to engrave on precious stones and on metals.
The tools, weapons, and ornaments of the ancient
Egyptians are in some cases elaborately engraved.
Chasing and carving, which are kindred arts, flourished in the kingdom watered by the
Nile.
Layard and his friends disinterred from the mounds of Nimroud, and at other places, many specimens of the graver's art; copper vessels, beautifully engraved, were among the number.
Carving in stone is closely allied to the above, and may be be termed engraving in stone.
Egypt is one triumphant vindication of the skill and industry of that nation in this particular.
The warlike
Osymandyas, nearly 200 years before Abraham, perpetuated upon granite the memory of his exploits, which reached as far as and included Bactria.
The temples, tombs, and obelisks of
Egypt, the sculptured palaces of
Nineveh, and the gorgeous rilievos of
Persepolis, attest the skill and fancy of the artists of the times
“Ere
Romulus and Remus.”
From
Egypt or Phoenicia the Greeks received the art of engraving, where it had considerably advanced in the time of
Homer.
Among other uses which are allied to chasing and inlaying, it was employed in delineating maps on metallic plates.
Specimens of Etrurian art are also of great antiquity, and we prudently do not enter the arena to settle the questions of precedence so lately revived by the wonderful discoveries of
General Di Cesnola, in
Cyprus.
In the temple of
Jupiter Capitolinus were stored 3,000 brass plates on which the laws of
Rome were engraved.
The ancient engraving was much of it complete enough for printing, but was generally intended for impressions in plastic material, clay, wax, and what not. (See seal.) It is, however, believed that parchment, linen, silk, and papyrus were sometimes impressed by the surface of the seal, previously blackened by ink or pigment.
Other than this, the first we know of engraving as a means of delivering an impression in ink or color was among the Chinese.
See printing.
The art of engraving is fairly referable to three divisions :
chalcography, or plate-engraving;
xylography, or wood-engraving;
lithography, or stone-engraving : the names being derived from the Greek words
chalcos, xylon, lithos, respectively, and the terminal
graphein, I write.
Engraving on metal originated with chasers and inlayers.
This art is very ancient, but does not seem to have suggested the sister art of printing from the plates thus engraved.
It appears singular that it did not, for a common mode of examining a piece of engraved work is to fill the engraved lines with a dark liquid, — the dirty oil, for instance, of the polishing rag, — so as to make visible the lines and the effect produced.
A piece of soft paper laid on this would obtain an impression, imperfect, it is true, but apparently sufficient to have suggested the art of copperplate printing.
In taking a cast in sulphur of some engraved church ornaments, it is stated that a Florentine artist named Finiguerra, about 1440, was led at length to the discovery of the value of plate-engraving as a means of printing.
Some dust and charcoal which had gathered in the lines came out upon the sulphur and gave an unexpected and suggestive effect.
Vasari records a similar mode of taking impressions in work, and states that “from these engravings the artists were in the habit of taking impressions by smoking them, and then, after cleaning the surface with oil, impressing upon the work a damp paper.”
The collections of impressions of these plates in the Florentine and other museums show that, previous to the time of Finiguerra, they are but proofs of inlayer's work, and that they were not made with a view to furnishing prints; the figures have their swords, pens, etc., in their left hands in the impressions, instead of the right.
Had they been engraved for the purpose of printing, the figures would have been reversed on the plate, so as to print right.
Euclid was printed with diagrams on copper in 1482.
The copperplate roller-press was invented in 1545.
Etching on copper by means of aqua-fortis invented by
F. Mazzuoli or Parmegiano, A. D. 1532.
Mezzotinto engraving invented by
De Siegen, 1643; improved by Prince Rupert, 1648; and by
Sir Christopher Wren, 1662.
“
Mr. Evelyn showed me most excellent painting in little [miniature]; in distemper, in Indian incke, water-colours : graveing; and, above all, the whole secret of mezzo-tinto, and the manner of it, which is very pretty, and good things done with it.” — Pepys's
Diary, Nov. 1, 1665.
At Gresham College, the Royal Society meeting,
Mr. Hooke explained to
Mr. Pepys “the art of drawing pictures by Prince Rupert's rule and machine and another of
Dr. Wren's [Sir Christopher]; but he [
Dr. Hooke] says nothing do like squares, or, which is best in the world, like a dark room.” — Pepys, Feb. 21, 1666.
These devices are apparently for copying; the
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former is probably on the principle of the pantograph; the squares is a familiar mode of reducing or enlarging by ruling off into equal numbers of squares the original and the paper on which it is copied.
The
dark room is probably the
camera-obscura, in the simple form of a hole in a shutter of a darkened apartment.
Cocker [the famous arithmetician] says, that the best light for his life to see a very small thing by, contrary to Chaucer's words to the Sun, that he
Should lend his light to them that small seals grave,
it should be by an artificial light of a candle, set to advantage as he could do it. — Pepys's Diary, Aug. 8, 1664.
“Come
Mr. Cocker, and brought me a globe of glasse, and a frame of oyled paper, as I desired, to show me the manner of his gaining light to grave by, and to lessen the glaringness of it at pleasure, by an oyled paper.
This I bought of him, giveing him a crowne for it; and so, well satisfied, he went away.” —
Ibid., Oct. 5, 1664.
Aquatint engraving invented by St. Non of
France, 1662.
Engraving in steel introduced into
England by
Perkins of
Philadelphia, 1819.
The earliest application of the wood-engraver's art in
Europe was in cutting blocks for playingcards.
The French writers ascribe it to the time of Charles V., but the Germans show cards of the date 1300.
The
Italians again claim that it originated in
Ravenna, about 1285.
An Italian pamphlet of the year 1299 speaks of cards as a gambling game, but these may have been drawn by the pen and colored by hand.
In the year 1441 the Venetian government forbade the importation of
stamped playing-cards as being injurious to their handicraft manufacture.
Ugo di Carpi introduced the method of printing in colors or tints by separate successive blocks.
Engraving on wood assumed the character of an art about 1440; the first impression, 1423.
Improved by Durer, 1471 – 1528; by
Bewick, 1789.
Engraving on stone. Work done upon a lithographic stone by etching-point, diamond, or rulingmachine : the stylus of the latter is a diamond.
There are two modes, the first of which is the more usual : 1.
The stone is covered with a gum and acid ink-resisting compound, dried, and the design scratched through this ground to such a depth merely as to expose the clean stone.
The stone is then oiled, the engraved portions alone absorbing the oil : it is afterwards washed, rolled up, and printed.
Printing is, however, usually done from transfers from the engraved stones.
2. The stone is etched through a ground of asphaltum; acid is applied to deepen the lines.
These are inked; the face cleaned off, gummed, and etched, the stone rolled up and printed.
Engraving is in many styles, and these are briefly considered under their respective heads, as follows : —
| Anaglyphtograph. | Chemitype. |
| Anastatic engraving. | Clamming-machine. |
| Aquatint. | Copperplate engraving. |
| Autopyrograph. | Counter-proof. |
| Banking. | Cradle. |
| Bite-in. | Cycloidal-engine. |
| Bridge. | Dabber. |
| Burin. | Daguerreotype etching. |
| Burnisher. | Diamond-point. |
| Cameo. | Die. |
| Celature. | Dotting. |
| Chalcography. | Draw-point. |
| Chalk-engraving. | Drive. |
| Chasing. | Dry-point. |
| Eccentric-engine. | Passe-partout. |
| Ectypography. | Photographic-engraving. |
| Electro-engraving. | Photograph-plate engraving. |
| Electro-etching. | |
| Electro-tint. | Proof. |
| Engraving. | Rebiting. |
| Engraving-machine. | Re-entering. |
| Engraving.
Photo- | Relief-line engraving. |
| Etching. | Reversing. |
| Etching-ground. | Rocker. |
| Etching on glass. | Rocking. |
| Etching-point. | Roulette. |
| Finishing. | Round-point. |
| Galvanograph. | Rubber. |
| Gem-engraving. | Ruling-machine. |
| Glass-engraving. | Scraper. |
| Graver. | Seal-engraving. |
| Ground. | Small chisel. |
| Grounding-tool. | Steel-plate engraving. |
| Intaglio. | Stipple. |
| Line-engraving. | Stopping. |
| Lithography. | Tint-tool. |
| Lithotint. | Transferring. |
| Lozenge-graver. | Transferring-machine. |
| Medallic-engraving. | Wood-engraving. |
| Mezzotint-engraving. | Xylography. |
| Niello. | Zincography. |
En-grav′ing-ma-chine.
1. A machine in which an intaglio impression is delivered upon a plate or cylinder for bank-note printing, or calico-printing, by the rotation under contact with the said object of a hardened steel roller (
mill) bearing the design in cameo.
This system was invented by
Jacob Perkins, and was first adopted in bank-note engraving.
(See transferring-machine.) The process for obtaining in the design in cameo on the
mill, by rotation in contact with an intaglio
die, is effected in a transfer press.
See also Clamming-machine.
A pantograph is used in etching a reduced copy of a pattern on to the copper cylinder for calico-printing.
Eccentric-engraving, for a certain class of patterns in calico-printing, is performed by a diamond etching-point on the varnished roller.
The points are moved by elaborate machinery, and the effect is analogous to that of the
eccentric and
rose-engine lathes.
2. An apparatus on the principle of the pantograph, but provided with a cutting device and machinery for causing pressure upon the surface to be engraved, so as to produce lines similar to those made by hand with the graver.
Collas (English patent) engraving-machine, 1830.
Electro-magnetic engraving-machine used in
Germany, 1854; in
America, 1858.
Guerrant and
Field's engraving-machine was patented in 1867, and was in operation in New York City during the year 1868.
To engrave by means of this machine the operator sits with a copy of the drawing, photograph, or whatever design is to be engraved, directly in front of him. A small pointer rests upon the drawing, and the whole operation consists in moving the pointer over the several lines of the copy.
The pointer is operated by two small cranks, one of which produces a vertical and the other a lateral movement; the simultaneous operation of both cranks producing a circular, inclined, or any desired irregular motion of the pointer, which is thus made to “follow copy.”
All the movements of the pointer are imparted, by means of a simple arrangement of levers, to a graver, which cuts or engraves the design upon the surface of a copper plate or block.
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At the
Paris Exposition of 1868, an apparatus was exhibited by
M. Gaiffe, of
Paris, for engraving by electro-magnetism.
It consists of two or more disks having their faces in the same vertical and their axes in the same horizontal plane.
The graving tools are provided with diamond points, and are connected with the armature of an electro-magnet, and with a tracing-point in contact with the patternplate.
The tracing-point and graver are caused to approach the centers of their respective plates by a gradual and uniform motion, forming a spiral of extremely close involutions.
A design is drawn on the pattern-plate in a non-conducting ink, and as the plates revolve together whenever the tracer crosses one of the lines of the pattern the circuit is broken, and the graver takes the metal of the plate to be engraved; when the tracer, on the contrary, is in immediate contact with the metal of the pattern, the graver is withdrawn from the plate to be engraved.
When the tracer has thus passed over all parts of the pattern-plate from the circumference to the center, a fac-simile of the pattern will have been engraved, in which, however, all the lines of the original will be represented by a series of dots.
The pattern may be reduced or enlarged by the application of the pantographic principle; and by the use of a series of gravers arranged on a pivoted bar at various distances from its center of motion, several copies may be made at the same time on scales proportioned to the distance of the gravers from this center.
En-larging-hammer.
The gold-beater's hammer, by which he reduces the package of
quartiers or gold-plate.
Fifty-six of the
quartiers form a package (
caucher), and are interleaved with vellum.
The hammer weighs fourteen or fifteen pounds, and is shaped like a truncated hexagonal pyramid, 6 inches high.
Its face is very slightly convex, and 5 inches diameter.
En-le-vage′--style.
A mode of calico-printing (which see).
E-nor′tho-trope.
A toy on the principle of the
thanmatrope, the
stroboscope, and
phenakistoscope, which depend for their action upon the persistence of visual impressions.
Upon different parts of a card are detached parts of a given figure, and when the card is rotated these become assembled and give a combined impression to the eye.
En-rock′ment.
Stone pitched on to the seaface of a breakwater or dike, or a shore subject to encroachment by the waves or stream.
En-tab′la-ture.
1. (
Architecture.) That portion of a classical structure which rests on the columns; it consists of an
architruve, frieze, and
cornice.
An attic or blocking-course is sometimes added.
Those members of a portico which were constructed upon the columns, consisted of the epistylium, zophorus, and corona.
2. (
Machinery.) A strong
iron frame supporting the paddle-shaft.
It usually receives additional stiffness from being confined between two beams of timber, called the
entablature or
engine-beams.
Enta-sis.
The swell of the shaft or columns of either of the orders of architecture.
En′ter-ing-chis′el.
A spoon-chisel; used by sculptors.
Enter-ing-file.
A narrow, flat file, with considerable taper, to enable it to enter and open a groove, which may be finished by a
cotter-file, for instance.
En′ter-ing-port.
（
Shipbuilding.) A port cut in the side of a vessel to serve as a door of entrance.
En-tero-tome.
An instrument for opening the intestinal canal through its whole extent.
It consists of a pair of scissors, one blade of which is made longer than the other, and rounded at its extremity.
This is passed into the intestine.
En-to-mome-ter.
An instrument for measuring the parts of insects.
En′trail-clean′ing ma-chine.
A machine for cleaning guts for sausage holders or strings.
Two rollers, revolving in opposite directions and armed with scrapingedges, are surmounted by elastic feed rollers, and provided each with an adjustable curved surface for pressing the entrails against the scrapingedges.
 |
|
Entrail-cleaner. |
En′tre-sol.
（
Architecture.) A low story or part of a story in a building, between two higher ones.
Intersol.
En-tro′pi-um For′ceps.
Forceps for grasping and returning to the natural position the eyelid, in which, by inversion, the eyelashes have become turned inwardly.
En′ve-lope.
1. A paper case to contain a folded letter.
2. (
Fortification.) The exterior line of works surrounding a fort or fortified position.
The besieged are said to be enveloped when completely surrounded by the works of the besiegers.
Enve-lope-ma-chine′.
The manufacture of envelopes is said to have been introduced by an English stationer named
Brewer, some fifty years ago. He cut them from the sheet with the aid of metallic formers, and folded and gummed them by hand with the brush, in the manner generally practiced until a comparatively recent period.
An envelope-machine was invented as far back as 1840, but
De la Rue's, 1845, appears to have been the first which achieved any notoriety.
Envelope-machines, so called, generally comprise only provisions for folding and gumming the envelope after it has been cut to the proper form.
The English envelope-machine, invented by
Hill and
De la Rue, operates upon diamond-shaped pieces of paper, which are successively placed on the platform.
A plunger descends and forces the central
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part of the paper into an oblong quadrangular cavity; the four corners stand erect and are successively flattened by four fingers.
When the folding is completed, two india-rubber fingers lightly touch the envelope and draw it aside to make room for another.
These fingers are small metallic cylinders with tips of india-rubber, which adhere sufficiently to the paper to retract it from its place in the machine and make room for another.
The gum is spread over an endless apron or blanket, and an artificial arm takes a supply and applies it to the envelope in its proper place, just before the flap is folded down.
As fast as the envelopes are made they are automatically ranged on an inclined plane and slide into a box. The machine (1853) made sixty a minute.
M. Remond's envelope-machine feeds the blanks by means of a pneumatic apparatus known as an aspirator, consisting of a hollow tube which is thrust forward and rests on the upper blank; the air is exhausted from the tube by an air-pump, and the blank becomes attached thereto by atmospheric pressure.
The tube is then withdrawn, removing the blank, which is dropped at the required place, by the relaxation of the atmospheric tension.
The machine of Robineau and Roumestant, exhibited at the
Paris Exposition of 1867, also lifts the blanks singly by atmospheric pressure, and folds them and gums them by a series of operations similar to those of
Remond's machine.
In another machine, the paper is fed in a continuous strip of a given width for a certain size envelope First are made transverse incisions, which answer for a portion of the division between the adjacent envelopes; the rectangular crease is made determining the size of the envelope, slits made from the corners of the latter to the edges of the paper; the included flaps are folded over and paste applied; the superfluous edge strip is cut off, and the angular division is made between the adjacent envelopes; the envelope is bent on the folding-line and passed between rollers, to be afterwards dried and have its flap gummed.
In
Keating's machine, the paper blanks are placed on a reciprocating feeder-plate
O and carried forward under the plunger
S by small hooks or projections.
The plunger descends, doubles the blanks by their contact with the creasing-rollers, and leaves the blank on a flat hinged bed, where the flap-folders are actuated to fold consecutively.
The auxiliary presser
s′ operates upon the gummed portion, starting directly after the gum-flap folder, which is cut away to allow its passage, and rises a little in advance of it. The counting apparatus is a ratchet and pawl arrangement.
E-o′li-an.
1. A frame with catgut strings which are vibrated by the wind.
See AeOLIAN.
2. An
eolian-attachment to a piano-forte is a supplementary arrangement of a bellows and set of reeds which are called into action at the discretion of the performer.
E-oli-pile.
The rotary steam-engine of Hero.
See AeOLIPILE.
E-paule.
（
Fortification.) The shoulder of a bastion; the salient angle formed by the face and flank.
E-paulement.
（
Fortification.) A species of breastwork formed to defend the flank of a post or any other place.
A work thrown up to defend troops from an attacking force; usually shoulder-high, hence the name epaulement.
E-pergne.
An ornamental stand for a large dish on a table.
Epi-cyclic train.
（
Gearing.) An epicyclic train is one in which the axes of the wheels revolve around a common center.
They are used for various purposes.
Several are shown under the heads equational box; sun and planet motion; parallel motion; epicycloidal wheel, etc.
Their forms are numerous, curious, and ingenious.
(See page 120,
Brown's “Five hundred and seven mechanical movements.” ) Quite a number of applications of the device have been made to harvestingmachines, in transmitting the motion of the drivingwheel axle to the cutter-bar.
a b c d are forms of epicyclic gearing.
The epicyclic train
b has some features in common with
Houldsworth's equational-box for regulating the relative speeds of the spindle with its flyer, and the bobbin, in the roving-frame.
If motion be imparted at the same speed and in the same direction to the loose wheels
D C, the effect is to revolve
B around the shaft
A without rotating
B on its axis
F G; they all move together as if pinned fast in a cluster.
 |
|
Epicyclic trains. |
If motion be imparted to the loose wheels
D C at the same speed in opposite directions, the effect is to rotate the wheel
B on its axis without revolving it on the common axis
A.
Unequal rates of motion of the wheels
D C, either in the same or opposite directions, will cause the wheel
B to rotate on its axis, and with its axis
F G to revolve around the common center
A.
In Entwistle's patent gear, three bevel gears of even size are thus associated, and the device is used for steering-apparatus, multiplying speed for screwpropellers, etc.
Driving from the other end of the train gives power with decrease of speed.
Many ingenious applications of the device might be cited and shown would space permit.
Epi-cy-cloid′al wheel.
An epicycloid is a curve generated by a point in the circumference of a movable circle, which rolls on the inside or outside of the circumference of a fixed circle.
See sun and planet motion, the invention of
Watt.
An epicycloidal wheel is a contrivance for securing parallel motion, in converting reciprocating mo-
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tion into circular, depending on the principle that an inner epicycloidal curve becomes a straight line when the diameter of the fixed circle is just double that of the rolling one.
It consists of a fixed ring, with teeth on the inside, into which is geared a wheel of half its diameter; to a pin on the circumference of the smaller wheel the reciprocating motion is communicated, while the center of the wheel describes a circle and may receive the pin of a crank whose shaft is concentric with the ring. — Webster.
 |
|
Epicycloidal wheel. |
Epin-glette.
An iron needle for piercing a cannon-cartridge before priming.
Eprou-vette.
1. An apparatus for proving the strength of gunpowder.
One simple mode is to fire weighed charges and ascertain the range of the balls.
A small quantity of powder, a heavy ball, and a short mortar reduce the range within convenient limits.
Another is to fire a small quantity beneath a shot attached at the foot of a vertical rod. The latter ascends, and, on reaching its greatest elevation, is prevented from descending by a pawl which engages a rack on the rod. The hight to which the shot ascends determines the strength of the powder.
The éprouvette of
Regnier is an adaptation of the Sector dynamometer.
A small brass cannon is attached to one are and charged with a given quantity of powder.
A projection from the other are comes in front of the muzzle, and the parts are separated when the explosion takes place.
A cursor over the graduations indicates the point reached by the force of the explosion.
See ballistic pendulum.
A convenient and portable éprouvette is an instrument shaped like a small pistol without a barrel, and having the forward end of its chargechamber closed by a flat plate connected with a spring.
On the explosion of the powder against the plate, the latter is driven forward to a distance proportioned to the strength of the powder, and is retained at its extreme range of propulsion by a ratchet-wheel and spring-click.
 |
|
Eprouvette. |
Pouillet's chronoscope and Navez's electro-ballistic apparatus, by measuring the velocity attained by balls with charges of certain powders, form good
éprouvettes. See chronoscope; electro-ballista.
2. (
Metallurgy.) A flux spoon.
A spoon for sampling an assay.
Eprou-vette — gun.
The gun-éprouvette determines the strength of the powder by the amount of recoil produced.
A small piece of ordnance is fastened to a frame which is suspended as a pendulum so as to vibrate in an are when the piece is fired.
A pointed iron rod projects downward from the gun, and travels in a groove of soft wax as the gun recoils, thus making a mark which is measured to determine the length of the are. A graduated are with an index-finger is used in the
British service.
The gun is of brass, 1 3/4 inch bore, 27.6 inches long, weighs 86 1/2 pounds; suspended from a frame and charged with two ounces of powder without shot or wadding.
The éprouvette-mortar of the
British service is 8 inches in diameter, and is charged with 2 ounces of the powder, and an iron ball of 68 1/2 pounds weight; average range of 265 feet. The government powder, somewhat deteriorated and reserved for blasting, gives a range of 240 feet.
The French éprouvette-mortar has a caliber of 7 inches; charge, 3 ounces; projectile, a copper globe of 60 pounds; required range, 300 yards.
The éprouvette-mortar of the
United States service is a 24-pounder, having a chamber to contain one ounce of powder, and no windage to the ball.
The required range for new powder, 250 feet.
Equal-ing-file.
A flat file which has a constant thickness, but may taper a little as to width.
Equal-iz-er.
An
evener or whiffletree to whose ends the
swingle-trees or
single-trees of the individual horses are attached.
A three-horse equalizer divides the load to three draft-animals.
See treble-tree.
 |
|
Equalizing-saw. |
E′qual-iz-ing-saw.
A pair of saws on a mandrel at a gaged distance apart, and used for squaring off the ends of boards and bringing them to dimensions.
E-qua′tion-al box.
Invented by
Houldsworth.
A differential gearing used in the bobbin and fly machine for the adjustment of different degrees of twist, for different yarns.
The bobbin and flyer are driven independently, and the arrangement affords a means of changing the relative speeds.
Two short cylinders
b p inclose bevel wheels 29 31.
Between the edges of these boxes is a spurwheel 28, driving a third bevel-wheel 30, mounted on an axis forming the radius of the spur-wheel, and occupying a slot in the
web of the wheel.
 |
|
Equational box. |
The wheel 30 has the same diameter and number of teeth as the wheels 29 31, with which it engages.
The wheel 29 is keyed to its shaft; but wheels 28 31 run loosely on the shaft and independently
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of it. Now, if wheel 28 be held still and wheel 29 be turned, the middle wheel 30 will act merely as a carrier between 29 and 31, which will turn with the same speed, but in opposite directions.
If 28 be turned at the same speed as 29 and in the same direction, the middle wheel 30 will not revolve on its axis, but acts
as a pin between 29 and 31, causing them to turn with the same speed and in the same direction.
These are the
extreme cases. The middle case is when 28 turns with half the speed of 29, in which case 31 does not revolve at all. All possible variations between the relative speeds of 29 and 31 can therefore be attained by changes of velocity in 28.
This is accomplished by putting a larger or smaller pinion on shaft
K, which has a regular rate of motion relatively to shaft
B.
Wheel 32 is joined to 31, and drives the
bobbins, whose speed is adjusted in any required ratio to that of the spindles and flyers, whatever may be the speed of the latter.
See bobbin-and-fly frame.
E-quation-watch.
A watch made to exhibit the differences between mean solar and apparent solar time.
Originally made in
England, but improved in
France.
Equa-tori-al.
A telescope mounted to follow the apparent motion of the heavenly bodies as they move in the sky. It revolves about an axis so inclined that its motion around it may be parallel to the equator.
Hence the name.
See telescope.
Equa-tori-al Sector.
An instrument of large radius for finding the difference in the right ascension and declination of two heavenly bodies.
Equa-to′ri-al Tel′e-scope.
The equatorial telescope is so mounted as to have a motion in two planes at right angles to each other; one parallel to the axis of the earth, and the other to the equator.
Each axis has a graduated circle, one for measuring declination and the other right ascension.
The right ascension and declination of an astronomical object being known, the telescope may be pointed to the spot.
Clock-work is sometimes attached to the instrument to give the motion in right ascension, and thereby keep the object constantly in the field of the instrument.
The large telescopes of the principal observatories are mounted equatorially.
See telescope. See also
Fig. 401, p. 175.
Equi-libri-um-valve.
（
Steam-engine.)
a. A valve having a pressure nearly equal on both sides, so as to make it more easily worked by nearly neutralizing its pressure on the seat.
The valve
D has packing on the back opposite to the two ports, so as to exclude the steam from behind it, and thus remove the pressure thereof.
A, cylinder ports.
B, central port leading to condenser.
C, parts of the valve-casing filled with steam.
D, equilibrium-valve.
E, packing ring on the back of the valve.
b. The valve in the steampassage of a Cornish engine for opening the communication between the top and bottom of the cylinder, to render the pressure equal on both sides of the piston.
 |
|
Equilibrium-valve. |
E-ras′ing-knife.
A knife with a cordate blade, sharpened on each edge, and adapted for erasing marks from paper by an abrading or cutting action, according to the angle at which it is held.
The ends are provided with burnishers, rubbers, pencilsharpeners, or other appendages useful about the desk.
An
eraser.
E-recting eye-piece.
（
Optics.) A combination of four lenses used for terrestrial telescopes, and so arranged as to exhibit the objects viewed in an erect position.
This is not deemed necessary in astronomical telescopes, as the additional lens required causes the reflection and absorption of a certain portion of light.
E-recting-glass.
A tube with two lenses, slipped into the inner end of the draw-tube of a microscope, and serving to erect the inverted image.
See Erector.
E-recting-prism.
A contrivance of
Nachet's for erecting the inverted image produced by a compound microscope, by means of a single rectangular prism placed over the eye-piece.
E-rect′or.
An arrangement to antagonize the inversion of the image formed by the object-glass, by again inverting the image to make it correspond in position with the object.
First applied to compound microscopes by
Lister.
It is a tube about three inches long, having a meniscus at one end and a plano-convex lens at the other, — the convex sides upward in each case, — and a diaphragm about half-way between them.
The
erector is screwed into the lower end of the draw-tube.
Eri-ome-ter.
An instrument for measuring the diameter of small fibers, such as wool, cotton, or flax, by ascertaining the diameter of any one of the colored rings which they produce.
“The
eriometer is formed of a piece of card or plate of brass, having an aperture of about one fiftieth of an inch in diameter in the center of a circle of one half inch in diameter, and perforated with small holes.
The fiber or particle to be measured is fixed in a slider, and the eriometer being placed before a strong light, and the eye assisted by a lens applied behind the small hole, the rings of colors will be seen.
The slider must then be drawn out or pushed in till the limit of the first
red and
green ring (the one selected by
Dr. Young) coincides with the circle of perforations, and the index will then show on the scale the size of the particle or fiber.” — Brewster's
Optics.
Es-cape.
（
Telegraphy.) Leakage of current from the line-wire to ground, caused usually by defective insulation and contact with partial conductors.
Es-capement.
A device intervening between the
power and the
time-measurer in a clock or watch, to convert a continuous rotary into an oscillating isochronous movement.
It is acted on by each.
The
power imparts through the escapement an impulse to the
pendulum or
balance-wheel sufficient to overcome the friction of the latter and the resistance of the atmosphere, and thus keeps up the vibrations.
The
time-measurer (
pendulum or
balance-wheel) acts through the escapement to cause the motion of the
train to be intermittent.
While there is some variation in the trains of clocks and watches, and in other particulars, they are generally named according to the form of their escapement; as, —
| Anchor-escapement. | Detached escapement. |
| Chronometer-escapement. | Duplex-escapement. |
| Crown-wheel escapement. | Electric-clock escapement. |
| Cylinder-escapement. | Horizontal escapement. |
| Dead-beat escapement. | Lever-escapement. |
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| Recoil-escapement. | Vertical escapement. |
| Remontoire-escapement. | (Which see.) |
| Verge-escapement. |
Goodrich, in 1799, substituted a crank for an escapement in clocks, and received a bounty of £ 65 from the London Society of Arts.
Its advantage was silence.
A number of curious and ingenious escapements may be found in works on horology, in
Denison's volume in
Weale's series;
Brown's “Five hundred and seven mechanical movements” ; and
Piaget's “The watch; its history and manufacture.”
Es-cape — valve.
（
Steam-engine.)
a. A loaded valve fitted to the end of the cylinder for the escape of the condensed steam, or of water carried mechanically from the boilers with the steam.
A
priming valve.
b. Escape-valves are also fitted to the feed-pipes as a means of exit for the surplus water not used by the boilers.
c. A valve which affords escape to steam in a given contingency; upon excessive pressure by a safety-valve; to announce low-water, etc.
Es-cape — wheel.
These are various in form; the wheel is acted upon by the spring or weight of the clock or watch, and is allowed an intermittent rotation, one tooth at a time, and the pendulum or balancewheel which thus regulates the movement becomes the time measurer.
The pallets on the oscillating pendulum arbor allow the teeth to escape, one at a time.
See escapement.
 |
|
Verge-escapement. |
Es-carp.
（
Fortification.) A wall on the inside of the ditch at the foot of the rampart.
On the other side of the ditch is the
counterscarp.
Escri-toire.
A writing-desk; generally fixed, and having a falling leaf.
Es-cutcheon; Scutcheon.
An ornamental plate for a name, as in a
coffin-plate, the
name-plate on the side of a pocket-knife, etc.; or a perforated plate to finish an opening, as the
key-hole plate of a door, drawer, or desk.
E-sopha-gus-forceps.
One for removing foreign matters from the gullet.
An esophagus-forceps, with bent shank, was found in 1819, in a house in
Pompeii, by
Dr. Savenko, of
St. Petersburg.
It is pictured in
Smith's “Dictionary of Antiquities,” p. 274.
Es-pal′ier.
（
Agriculture.) A trellis for training vines or other plants.
Espla-nade.
（
Fortification.) An extended glacis.
The sloping of the parapet of the covered way toward the open country.
A clear space between the citadel and the adjacent houses of a fortified town.
Esta-cade′.
（
Fortification.) A line of pile stakes in water or swampy ground to check the approach of an enemy.
Es — the si-ome-ter.
（
Surgical.) An instrument to ascertain the tactile sensibility of the human body.
It has two points, adjustable as to distance, and the object is to ascertain the nearest proximity at which the points give distinct sensations.
The result is indicative of a normal or abnormal condition of the surface.
In front of the ear the points may be three quarters of an inch apart, and give but a single sensation; but if you draw them lightly across the face to the other ear, at a certain point the single sensation will change into a double sensation; as they approach the mouth, they will seem to separate more widely, and on the other side of the face they will seem to draw together again, until the double impression is lost in a single one.
(See nerve-needle.) An anatomist (
Rufus, of
Ephesus) dissected apes and distinguished between nerves of sensation and of motion.
Es-trade′.
A slightly raised platform, occupying a part of a room.
It may form a
dais.
Eta-gere.
A set of shelves in the form of an ornamental standing-piece of furniture.
Used for the display of articles of hijouterie and vertu.
Etching.
1. (
On metal.) Engraving executed by a pointed tool and acid upon a metallic or glass surface previously covered with varnish.
The ordinary procedure is as follows : Cover a polished metallic plate with a composition technically called
ground, and consisting of asphaltum, 4 parts; Burgundy pitch, 2 parts; white wax, 1 part.
For use, this is melted and compounded, and tied up in a silk rag. The plate is heated, rubbed with the ground, which is then spread evenly, smoked, and allowed to cool.
The design is traced by a pointed tool, called an etching-point, which lays bare the metal wherever it goes.
This finished, a wall of wax is raised around the design to hold the dilute acid which is poured on. For a copper-plate, this consists of nitrous acid, 1 part; water, 5 parts.
For steel, pyroligneous acid, 1 part; nitric acid, 1 part; water, 6 parts.
This is poured on the plate, which it corrodes on the lines made through the “ground.”
This is called “biting-in.”
The etching is swept with a feather to remove the bubbles from the surface, or, in case of a steel-plate, agitation may answer the purpose.
When a sufficient depth is attained for the lighter tints of the etching, the acid is removed, the surface washed and allowed to drain dry. The parts having sufficient depth are now “stopped out” by a varnish of Brunswick-black laid on with a camel's-hair brush.
When the varnish is dry, another “biting-in” will deepen the lines of the parts not “stopped out,” and when these parts are deep enough for the second tint, the varnish is removed, the plate dried, etc. This is repeated as many times as may be necessary.
The wall of wax is then removed, the surface of the plate cleaned with turpentine, and the plate is sent to the printer for a proof of the etching, which is complete.
It may be finished by a graver to give it more effectiveness, but it then partakes of the character of a line engraving.
Etching is
all accomplished by the point and acid.
The art is believed to have originated in
Germany, judging by its name
etzen; but the earliest known practitioners were
Albert Durer, a German, and Agostino Veneziano and Parmegiano, Italians.
These were contemporaries.
Etching on soft ground is in imitation of chalk or pencil drawing, but has been abandoned since lithography has attained excellence.
The soft ground is made by adding one part of hog's lard to three parts etching
ground (see ground), which is laid on the plate with the dabber in the usual way. A piece of smooth writing-paper, having the design in outline, is damped and stretched over the plate.
A pencil is then used to follow the lines of the design, observing that the softer the
ground the softer the pencil should be. The temperature of the season or the room will affect the character of the
ground. When the paper is removed, it withdraws the adhering lines of ground, and the plate is
bitten-in in the usual way.
[
810]
Several peculiar processes have been introduced in etching, but are rather curious than useful.
Electro-etching, so called, is a process of
biting-in, rather than
etching, and consists in exposing the etched plate in the electro-bath, as the copper of the battery, so as to be corroded by the voltaic action.
See electro-etching.
Daguerreotype-etching is a process wherein the dark lines of the image in the camera are made to expose the plate to the action of acid.
One mode of etching, the reverse of the usual plan, is to remove with point and scraper the lights, and then bite — in so as to expose the design in relief.
2. (
Glass.) Fluoric acid was discovered by Scheele in 1771. One hundred years previous to this, Schwanhard had a secret process for etching glass, but his secret died with him. See etching on glass.
3. (
Lithographing.)
a. The preparation of a lithographic stone with a weak mineral acid after the drawing or transfer has been put upon its surface; the object being to fix and render such drawing capable of receiving the ink used in printing.
The crayon or ink of the artist is essentially based upon an alkaline soap combined with wax, resins, and pigment, the latter being added merely for the purpose of enabling the artist to see the progress of the work; drawings made with crayons and the ink used in pen-work are soluble, and hence not fit to resist the damping process on the stone; nor is the stone under them fit to receive the printing-ink.
The action of a very weak acid applied to the stone by a large soft brush, a sponge, or by flooding it, is to decompose the alkaline soaps, forming nitrates or chlorides of the alkaline metals, according to the acid used, and setting free the stearic and oleic acids simultaneously.
These fatty acids isolated in intimate contact with the carbonate of lime, of which the stone is mainly composed, appear to enter into chemical combination with the same, driving out the carbonic acid.
The insoluble lime-soap thus formed has an exceedingly strong affinity for greasy matters of all kinds, and readily accumulates upon its surface the “varnish” (burned
linseed-oil) constituting the vehicle carrying the carbonaceous matter which gives the printing-ink its color.
Another function of the weak acid is performed upon the clean part of the stone, whereby it renders the particles of calcareous matter peculiarly susceptible to receiving and holding, despite the longcontinued damping operations upon the stone, the covering of gum-arabic furnished by the operation of gumming (which see). The gum is often applied with the acidulous solution.
Sulphuric acid cannot be used in etching, in consequence of the production of insoluble sulphate of lime.
b. Etching by a needle or diamond on stone is done in two ways : —
1. The surface of the stone is treated with gum and acid (an ink-resisting compound), and dried; the work is then scratched in by the etching-point.
Oil is rubbed over the surface, which is resisted by the gum, but penetrates where the stone has been laid bare by the needle.
The stone is then washed off, rolled up and printed.
This is usually called engraving.
2. The surface of the stone is covered with an asphaltum ground; the work is etched in, cutting away so much of the ground and exposing the stone.
Acid is then applied, which eats away the stone, making a depression; this is inked, the asphaltum cleaned off, the clear spaces etched, and gummed as usual in the lithographic process.
Etching-needle.
A sharp-pointed instrument for scratching away the
ground on a prepared plate, preparatory to the
biting-in.
Etching on glass.
This art was invented by Schwanhard of
Nuremberg, 1670, and originated in an accident to his spectacles, which became corroded by some drops of acid.
Fluoric acid, discovered by Scheele, 1771, is now employed for corroding, or, as it is technically called, “biting-in” the etching.
The glass is covered with a resinous ground, and the design marked by an etching-point, exposing the glass.
The latter is then subjected to an acid, which acts upon the silicate and eats away the glass at these points, making depressions which constitute the etching.
Etching-point.
The steel or diamond point of the etcher.
Etching-varnish.
A compound of wax, asphaltum, pitch, etc., for spreading on plates which are to be etched.
See ground.
E′ther-en′gine.
See bisulphide of carbon engine; air-engine; gas-engine.
E-tui′.
A case for holding small articles, as a lady's work-box and case for articles of graceful needle-work.
Eudi-ome-ter.
Dr. Priestley, the discoverer of oxygen gas, devised the first
eudiometer, for ascertaining the quantity of oxygen contained in a given bulk of aeriform fluid.
His device was founded upon the idea of subjecting a measured volume of air to a substance which would
absorb the oxygen of the air. For this purpose he used deutoxide of nitrogen, which has an energetic tendency to regain the oxygen of which it has been deprived, and resume its condition as nitric acid.
Scheele's eudiometer was a tube of known capacity, in which a body of air was exposed to a mixture of sulphur and iron filings made into a paste with water.
This abstracted the oxygen of the air, but an evolution of hydrogen somewhat marred the accuracy of the result.
De Marte used as an oxygen absorbent a solution of sulphuret of potassium.
Guyton used the same material, and added heat to expedite the result.
See “
Nicholson's journal,” 4to, Vol.
I.
Seguin used a glass tube filled with and inverted in mercury.
A piece of phosphorus, being introduced, floated to the top of the mercury, and was melted by the approach of a hot iron.
Air is then introduced in instalments, and, igniting the phosphorus, parts with its oxygen thereto.
A measured quantity having been thus introduced, the remainder in the tube is transferred to a graduated tube, and the loss of bulk by oxidation is determined.
Berthollet used the slow combustion of phosphorus, dispensing with the application of artificial heat.
Hope contrived a
eudiometer in which a graduated tube containing a cubic inch of air was inverted into a phial containing the oxygen-absorbing solution.
The apparatus, being tight, permitted the contents to be agitated.
As gas was absorbed, water was admitted to the phial, and the rise of the liquid in the graduated tube indicated the amount of the gaseous remainder.
Henry substituted a caoutchouc ball for the phial in
Hope's instrument.
Pepys made a number of technical improvements, which he considered insured accuracy, but certainly complicated the apparatus.
Volta introduced an instrument which superseded the preceding.
He determined the composition of the air by combustion with a known quantity of hydrogen gas.
[
811]
It is founded on the principle that when a mixture of oxygen and hydrogen gases is fired, one third of the diminution is owing to the condensation of oxygen.
For this purpose he used a graduated tube and two platinum points, between which an electric spark was caused to pass.
This was modified in construction by
Mitscherlich and others, retaining the main idea.
 |
|
Ure's eudiometer |
Ure's eudiometer is founded on the Volta principle, but is much simplified in point of manipulation.
It consists of a graduated glass siphon whose open extremity is slightly flaring.
The other end is closed, and has two platinum wires.
Being filled with water or mercury, the closed leg receives a volume of gas by the ordinary means.
A couple of inches of water being displaced from the open end of the tube, the mouth is closed by the thumb, and the instrument approached to the electric conductor, a spark from which, leaping the interval between the end wires, explodes the gases.
The rise of the water in the closed end indicates the volume removed, and the result is determined, as before explained, by reference to the graduated tube.
If merely oxygen and hydrogen gases have been introduced in their proper atomic proportions, eight of the former and one of the latter, by weight, the result will be water without gaseous remainder.
If the experiment be as first stated: A given volume of hydrogen introduced in company with a body of atmospheric air to be tested; one third the amount of condensation may be ascribed to the removal of oxygen, whose proportions for combining with hydrogen to form water are, oxygen 1, hydrogen 2, by bulk.
The space between the thumb and the surface of the water in the open leg forms an air-cushion when the gases explode.
Dobereiner's is founded upon the power of spongy platinum to cause the combination of oxygen and hydrogen gas. The labors of
Bunsen,
Regnault, and Reiset,
Williamson and
Russell,
Franklin and
Ward, have brought the instrument to the present efficient form.
Eu′phroe.
A long slat of wood, perforated for the passage of the awning-cords which suspend the ridge of an awning.
The
euphroe (or
uphroe) and its pendent cords from a
crow-foot
Eu′style.
（
Architecture.) That style of intercolumniation in which the space between the columns was 2 1/2 times their diameter; so called from being considered the most beautiful style.
E-vap′o-rating-cone.
A Belgian evaporator, consisting of a hollow cone with double walls, between which is a body of steam.
Over the inner and outer surface of the cone a saccharine solution runs in a thin film, and is thereby heated.
It is similar in principle to the
Deyrond condenser. See condenser; evaporator.
It is the same in its principle of construction as certain coolers, in which a refrigerating liquid fills the jacket, over whose walls passes the liquid to be cooled.
E-vap′o-rating-fur′nace.
The furnace of a boiler for cane-juice, sirup, brine, etc.
E-vapo-ra′tion-gage.
A graduated glass measure, with wire-gauze cover to prevent access of insects, to determine the ratio of evaporation in a given exposure.
E-vap′o-ra-tor.
An apparatus consisting of a furnace and pan, in which vegetable juices are condensed.
The varieties are numerous: intended for the sugar-house of the plantation, that of the refinery; for maple-sugar making and for sorghum; for making vegetable extracts for medicines and other purposes.
Those which boil
in (partial)
vacuo are known as vacuum-pans (which see). Some drive off a part of the aqeous fluid, and are called
condensers, such as the Degrand.
See condenser.
 |
|
Evaporators |
A “set of kettles” in
Louisiana consists of five, placed in line, and with their tops on the same level.
Underneath is a furnace, the mouth of which is outside the building.
The kettles are technically known as the
grande, propre, flambeau, sirop, and the
batterie. The
grande receives the cane-juice from the mill, and is the farthest removed from the mouth of the furnace.
The scum, as it rises, is swept towards the rear from kettle to kettle, and the juice, as the kettles empty by evaporation, is dipped from one to the other towards the
batterie. From the latter it is dipped into a box whose conducting troughs lead it to the
coolers.
Hoard's pan, patent 1838 (
A,
Fig. 1887), has a trough around to collect scum, and tubular flues passing through the boiler.
The steam-pan, first introduced in
Louisiana in 1829, had a serpentine coil at the bottom of a circular pan.
Stillman's pan (
B), 1846, had a series of bends connecting with a tube which also formed an axis for the system which could thus be erected so as to expose the bottom of the pan.
A combination of the open pan and vacuum-pan has been adopted to some extent in
Louisiana, and
[
812]
probably elsewhere.
The cane-juice being concentrated in open kettles to about 26° or 28°
Baume and then finished in the vacuum-pan.
It requires no special notice.
The Duplessis plan, 1846, consists in heating the juice in pans with double bottoms, forming steam-jackets, and then finishing it in kettles let into the top of a horizontal cylindrical boiler, which is pierced with holes for that purpose.
The flanges of the kettles are bolted steam-tight to the top plate of the steam-boiler, which has an inclination from front to rear to facilitate the transfer of the scum to a trough at the lower end.
Graham's apparatus, 1843, has a series of kettles in a rising order towards the rear, like steps, so that the
grande may empty into the
flambeau, that into the
sirop, and the latter into the
batterie, without dipping.
They are of progressively smaller size to the lower end of the series, and are heated by steamjackets.
The pans are connected by pipes furnished with stop-cocks.
A connected history of the process of manufacturing sugar is given under sugar-manufacturing, and some things are omitted in this to avoid duplication.
See also condenser, Degrand, which acts as an evaporator of the sirup poured over it, while it condenses the vapor from the vacuum-pan with which it is charged.
See vacuum-pan.
The
Wetzel pan is heated by steam.
It is a long tank with a semi-cylindrical lower portion in which revolves a hollow wheel heated by a constant flow of steam.
Drums on the shaft are also full of steam, and are connected by pipes, steam-heated.
Revolving slowly, it exposes a considerable surface to and agitates the sirup, which constantly drips off that portion exposed to the air.
The Bour pan is somewhat similar, but the revolving, heating surface is made up of steam-heated drums on a shaft, revolving in a pan having a semicylindrical well.
The evaporating cone
C of Lembeck, near
Brussels, consists of a double-walled cone
c c about 16 feet high, and heated by steam in the space intervening between the walls.
Sirup from the cistern
s flows by the faucet
c′ into the funnel
f, and thence is distributed by openings so as to run in a thin film over the interior surface of the cone
c. A ballcock keeps a constant level in the cistern
p. To prevent the liquid running in streams down the surface of the cone, it is again and again arrested by the hollow conical frustums, which divide any trickling streams and redistribute them over the heated surface.
These frustums are strung upon a stem
a a, so as to be removed in a body when required for cleansing.
The exterior surface of the cone receives a film of the sirup from the same cistern, the spout conducting it into the trough
r from whence it reaches the surface of the cone.
It is again and again arrested by exterior funnel-shaped troughs
m m, and allowed to trickle therefrom at openings along the meeting edge of the trough with the cone.
This breaks up any determination to run in streams, and keeps the evaporating surface evenly supplied.
An annular reservoir receives the condensed liquid, whence it is conducted by a spout
t to a cistern
w.
The apparatus is especially designed for beet-root sugar-making.
The
Degrand or
Derosne condenser is an evaporator used in the cane-sugar works, and consists of a column of horizontal, steam-heated pipes over which the cane-juice trickles, and eventually passes in a condensed condition into a cistern below.
See condenser.
A class of inventions known as
coolers agree in many points of construction with these surface condensers; the main difference being in the fact that in one case the hollow trunk is filled with a refrigerating liquid and in the other with steam.
Useful hints may be taken from beer-coolers; liquid-coolers (which see).
One form of apparatus consists of a number of hollow disks of lenticular figure, arranged upon a common axis, and dipping into the liquid to be evaporated.
These disks, or lenses, are constructed of thin metal, and are all in communication with each other through the common axis, which is likewise hollow.
The whole system is kept in slow rotary motion by some convenient moving power, and each disk carries up with it, adhering to its surface, a thin film of the liquid; as evaporation when it takes place without ebullition goes on with a rapidity proportional to the surface exposed.
Of this class is
Schroder's evaporator
D, used in the
West Indies, for evaporating saccharine juices at a temperature not exceeding 180° it is worked by hand or steam power.
It is intended specially as a substitute for the
teache, and consists of a semi-cylindrical pan
h, whose contents are heated by a steam coil
d d, connecting by pipe
g with the boiler.
On a longitudinal axle resting in boxes on the ends of the pan are a number of disks
j, which are rotated by power applied to the crank.
As these disks are alternately exposed to the sirup and to the air, the latter has free access to the moistened surface, and carries off the aqueous particles with considerable rapidity.
n is the discharge-pipe, which is opened by a faucet in the usual manner.
The machine stands isolated on the floor of the sugarhouse, and is supported on an iron stand.
 |
|
Sorghum-evaporators. |
A modification of this plan is the Cleland evaporator (
English), in which the rotating device consists of a spiral coil of steam-pipe receiving steam through the trunnions and immersed during a portion of its revolution in the sirup of the pan. It differs from the
Schroder pan in the fact that the rotating device is hollow and steam-heated so as to make the action more energetic, the film of sirup on the coil being exposed to the heat of the interior steam and to the evaporative action of the surrounding atmosphere.
[
813]
Fig. 1888 shows two forms of sorghum-evaporators, in the upper one of which are reciprocating paddles for removing scum from the heated juice and sweeping it towards the cooler overhanging shallower parts at the edges of the pan. The lower figure shows a series of pans with connecting apertures stopped by gates.
 |
|
Portable evaporator |
Fig. 1889 shows a portable evaporator mounted on a wheelbarrow.
 |
|
Continuous-steam evaporator |
Fig. 1890 shows an evaporator in which a continuous stream of juice is allowed to flow in a sinuous track from end to end of the pan, which is so mounted as to be inclined in any required degree, according to the condition of the fire or of the juice, so that it may reach the end in the desired condition of condensation.
 |
|
Salt-pan. |
A pan for the evaporation of water from brine is an oblong square, and may have a depth of 12 to 16 inches, and an area of 20 × 40 feet. The pan is made of sheetiron, supported on the division walls between the furnaces, which are in number proportioned to the width of the pan. The fire from the furnaces is conducted to heatovens before being discharged into the chimney.
The brine is led into the pan by pipes, and under ordinary circumstances may be twice changed in twenty-four hours. As soon as most of the water has been evaporated, the wet salt is ladled into conical baskets which are placed against the bench to drain.
The salt is finally dried in the ovens heated by the furnace fires.
The cocoa-nut palm yields a juice (
suri), which is evaporated to make a sugar (
jaghery), one gallon of
sari yielding a pound of
jaghery. This is live times the quantity to the gallon that is yielded by the sugar-maple.
The suri is obtained by cutting the spadix of the tree and collecting the juice in a crock suspended from the spathe.
 |
|
Evaporometer. |
E-vapo-rom′e-ter.
An
atmometer or
hygroscope, for ascertaining the evaporation of liquids.
The example shows a self-recording evaporometer or tide-gage, adapted also for a rain-gage or to indicate the rise and fall of any body of water in a river, canal, or lock, showing the exact time at which any increase or reduction of level may have occurred.
a is a time-piece driving the paper cylinder
g; b is the carriage which carries the tracing-pencil that marks the paper on the cylinder, and is moved by the float which is suspended from the card
f and rests on the surface of the water.
The motion of the float is communicated by cord
f over small wheel
e, float-wheel
d, and pulley
c.
 |
|
Evener. |
E′ven-er.
A double or treble tree, to “even” or divide the work of pulling upon the respective horses.
It is swiveled to the pole, usually by a bolt or wagon hammer, and has clips on the ends to which the middle clips of the single trees are attached.
Ev′er-point′ed Pen′cil.
A pencil-case having a fine cylinder of graphite, which is brought forward by a screw as fast as wear renders it necessary.
Patented by
Hawkins and Mordan,
England, 1823.
The pencil-case has a slider actuated by a screw to project a little cylinder of black-lead as the latter wears away.
The lead is so small in diameter that it does not need cutting for the ordinary purposes of a pencil.
The projection of the lead is performed by holding the nozzle in one hand and turning round the pencil-case with the other.
A reservoir at the end of the holder contains a supply of spare leads.
[
814]
Ew′er.
A toilet-pitcher with a wide spout.
Ex′ca-va tor.
1. A machine for digging earth and removing it from the hole.
This definition does not distinguish the
excavator from the
ditching-machine, auger, dredge, earth-borer, post-hole digger, etc. Custom, however, confines the term
excavator to a narrower range.
 |
|
Ditch-excavator. |
The excavator, which is of the nature of a plow, with an elevating earth-belt, is shown in
Fig. 1894. It has adjustment for depth of cut, and the dirt excavated by the hollow share is carried upwardly and backwardly by the shovel-belt and dropped into the chute, which discharges it at the side of the trench.
Willard's excavator, which has been so widely used in making railway embankments in the broad
West, is shown in
Fig. 1895. Its principal use in practice has been to dig soil by the side of the track and dump it on to the road, to form a bed for the ballast and sleepers.
The earth is scraped up by the shovel, carried between the wheel and a traveling apron, and dropped into a hopper.
When this is full, the machine is drawn on to the site of the road and the load dumped.
The excavator (
Fig. 1896) is mounted on a carriage which traverses on a temporary track.
At one end of the frame is a crane, which has a circular adjustment on its axial post.
To the end of the chain-tackle is suspended a scoop made of boiler-iron, whose lip is a steel edge with fingers.
Direction is given to the scoop by means of a beam which may be called the scoop-handle, and when the scoop has been thrust by its weight into the earth, the beam affords a fulcrum on which the scoop rotates when the tacklechain is wound up on the drum by the action of the steam-engine.
The excavated earth along some parts of the line of the
Suez Canal was transported by means of a pump.
By the aid of a steam-pump water was mixed with the earth brought up by the dredge, and the mud so formed was spouted out upon both banks of the canal to such a distance and in such quantities as to form high compact ramparts against the sand showers blowing in from the desert.
Ninetysix million cubic yards of earth have been taken out; and there is left to-day a canal 90 miles long, 328 feet wide at the surface, and 74 feet wide at the bottom, and 26 feet deep throughout.
See dredgingmachine.
[
815]
The practice adopted in the
United States, in
France, in
England, and
Holland is to mix such earth
in situ and pump it up, mud, earth, sand, and all, — and pour it into lighters or directly upon the land adjacent.
The hydraulic mining of
California is by means of powerful jets of water projected against the banks of drift, the
debris of former periods of glacial and fluvial action.
See auger; ditching-machine; dredging-machine; scraper; well-boring.
Number of Cubic Feet of various Earths in a Ton.
| Loose earth | 24 |
| Coarse sand | 18.6 |
| Clay | 18.6 |
| Earth with gravel | 17.8 |
| Clay with gravel | 14.4 |
| Common soil | 15.6 |
2. A dentist's instrument for removing the carious portion of a tooth.
They are of various forms and sizes, straight, curved, angular, and hooked; and may be compared to chisels, gouges, scropers, scrapers; spear, hoe, hatchet, spade or spoon shaped, etc.
 |
|
Excelsior-machine. |
Ex-cel′si-or.
A trade name for curled shreds of wood used as a substitute for curled hair in stuffing cushions, etc.
It is made in a machine in which the bolt is pressed downward within its fixed case by a weighted lever, and subjected to the action of the scoring and plane cutters at the upper surface of the horizontal rotating wheel.
Ex-change′--cap.
A fine quality of paper made of new stock; thin, highly calendered, and used for printing bills of exchange, etc.
Excla-ma′tion.
Note of. A mark (!) indicating emotion or pointed address; as —
“Father of all!”
Ex′edra.
（
Architecture.) A niche projecting beyond the general plan of a building.
Ex′er-cising-appa-ra′tus.
An apparatus for the use of gymnasts, or for the training of special muscles.
In the example, the hand-bar is supported on an adjustable cord passing over a spring.
The frame has two spring-boards near the floor.
In other instances the apparatus is intended for the use of those unable to take walking exercise.
The bedridden patient uses the arms to flex and extend the legs and keep the body in motion, the bedstead rocking on its centers.
Lounde's English patent, 1796, described a
gymnasticon with treadles for the feet and cranks for the arms.
It is adapted to exercise a limb which may have no voluntary motion, and may be used by a patient sitting, standing, or lying.
Ex-haust′er.
（
Gas-making.) An apparatus by which reflex pressure of gas upon the retorts is prevented.
The forms are various; one consists of a
 |
|
Gymnasts' machine. |
 |
|
Exercising-apparatus. |
device like one form of rotary steam-engine, which has an eccentric, revolving hub and sliding piston in a cylindrical chamber.
It is of the nature of a rotary pump.
Ex-haust′--fan.
One in which the circulation is obtained by
vacuum, in contradistinction to that which acts by
plenum, forcing a body of air into and through a chamber or passage-way.
See blower; fan.
Ex-haust′ing-syr′inge.
A syringe with its valves so arranged as to withdraw the air from the object to which it is applied.
Ex-haust′--port.
（
Steam-engine.) The passage leading from the cylinder to the condenser or to the open air.
Ex-haust′--pipe.
One conducting the spent steam from the cylinder.
Ex-haust′--reg′u-lator.
A valve adjusted to the pressure of the steam by compressing or relaxing the spring held within the tube, by means of a disk secured to the end of the spindle, the object being to utilize the exhaust steam.
 |
|
Exhaust-regulator. |
Ex-haust′ steam.
（
Steam-engine.) Steam which passes out of the cylinder after having performed its function.
It is emitted by its own pressure when the exhaust-valve is opened, and its ejection is
[
816]
assisted by the advancing piston, which is being driven by the
live steam behind it.
Ex-haust′--valve.
（
Steam-engine.) The valve which governs the opening by which steam is allowed to escape.
The
eduction-valve.
The valve in the eduction passage of the steam cylinder of a Cornish engine, placed between the cylinder and airpump, and worked by the tappet motion, so as to open shortly after the equilibriumvalve, and admit the steam to the condenser.
Ex-pand′ing-al-loy′
Such as expands in cooling.
They always contain bismuth, and usually antimony.
Typemetal is a familiar instance.
Ex-pand′ing-ball.
One having a hollow conical base, affording a relatively thin body of metal, which is expanded by the force of the explosion, driving it closely against the bore of the gun and into the rifling, preventing windage.
Ex-pand′ing-bit.
A boring-tool whose diameter is adjustable.
See auger; bit.
Ex-pand′ing-drill.
One having a pair of bits which may be diverged at a given depth to widen a hole at a certain point; used in drills for metal and for rock-boring.
Ex-pand′ing-man′drel.
One having fins expansible in radial slots to bind against the inside surfaces of rings, sleeves, or circular cutters placed thereon.
Ex-pand′ing-plow.
One having two or more shares, which may be set more or less distant, according to the distances between the rows at which different crops are planted.
Ex-pand′ing-pul′ley.
One whose perimeter is made expansible, as a means of varying the speed of the belt thereon.
See expansion-drum.
Ex-pand′ing-ream′er.
One which has a bit or bits extensible radially after entering a hole, so as to enlarge the hole below the surface.
Ex-pan′sion.
1. The expansion and contraction of long beams from changes in temperature is shown by the following table, which exhibits the extension dilatation in passing from 32° to 212° Fah. (0° to 100° centigrade).
The table exhibits the expansion at 212°, the length of the bar at 32° = 1.
| Bismuth | 1.00139 |
| Brass | 1.00216 |
| Copper | 1.00181 |
| Bronze | 1.00184 |
| Gold | 1.0015 |
| Cast-iron | 1.00111 |
| Wrought-iron | 1.00125 |
| Steel | 1.0011 |
| Lead | 1.0029 |
| Platinum | 1.0009 |
| Silver | 1.002 |
| Tin | 1.002 |
| Zinc | 1.00294 |
| Brick, common | 1.00355 |
| Brick, fire | 1.0005 |
| Cement | 1.00143 |
| Glass (average) | 1.0009 |
| Granite | 1.0008 |
| Marble | 1.0011 |
| Sandstone | 1.0017 |
| Slate | 1.00104 |
| Pine (along the grain; dry) | 1.000428 |
| Honduras Bay wood (along the grain; dry) | 1.000461 |
| Water at 40° = 1 | 1.0401 |
| Air | 1.376 |
2. (
Shipbuilding.) The expansion of the skin of a ship, or rather of a net-work of lines on that surface, is a process of drafting to facilitate the layingoff of the dimensions and positions of the pieces of which that skin is to be made, whether timber planks or iron plates.
It consists in covering the surface with a network of two sets of covers, which cross each other so as to form four-sided meshes; then conceiving the sides of those meshes to be inextensible strings, and drawing the net-work as it would appear if spread flat upon a plane.
By this operation, the meshes are both distorted and altered in area; the curves forming the net-work preserve their true lengths, but not their true angles of intersection; and all other lines on the surface are altered both in length and in relative angular position.
The process is applied to surfaces not truly developable.
See development.
3. (
Steam.) The principle of working steam expansively was discovered by
Watt, and was the subject-matter of his patent of 1782.
By it the supply of steam from the boiler to the cylinder is
cut off when the latter is only partially filled, the remainder of the stroke of the piston being completed by the expansion of the steam already admitted.
The work done by a given amount of steam is greater when worked expansively than when worked at full pressure, in the following ratio: —
| Point of cutting off. | Mean Pressure of Steam | Gain per Cent in Power. | Point of cutting off. | Mean Pressure of Steam. | Gain per Cent in Power. |
| .1 | 3.302 | 230. | .5 | 1.693 | 69.3 |
| .125 | 3.079 | 208. | .6 | 1.507 | 50.7 |
| .166 | 2.791 | 179. | .625 | 1.47 | 47. |
| .2 | 2.609 | 161. | .666 | 1.405 | 40.5 |
| .25 | 2.386 | 139. | .7 | 1.351 | 35.1 |
| .3 | 2.203 | 120. | .75 | 1.285 | 22.3 |
| .333 | 2.099 | 110. | .8 | 1.223 | 20.5 |
| .375 | 1.978 | 97.8 | .875 | 1.131 | 13.1 |
| .4 | 1.916 | 91.6 | .9 | 1.104 | 10.4 |
No deductions are here made for a reduction of the temperature of the steam while expanding or for loss by back pressure.
Ex-pan′sion-coup′ling.
The coupling represented consists of an expansion-drum of thin copper
x between the extremities of two pipes
a i,
Fig. 1901, which, in elongating, press the sides of the drum in, and draw them out in cooling.
Ex-pan′sion-drum.
An arrangement by which an occasional change of speed may be effected.
The diameter of one of the drums is made variable, and the belt is kept strained by means of the weighted roller
a. The part of the
expansion-drum marked
b, consisting of a boss and grooved arms, is keyed fast on the shaft; on to another portion of the arm
c, which slides up and down, in the groove of
b, is cast a portion of the circumference of the drum; it has also a stud
d, fitting into the curved slot of the disk
e, which moves loose on the boss
b, and has teeth on its circumference into which works a pinion
f, with ratchet fixed to the part
b, and turned with a handle.
As the disk is to turned the right or
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817]
 |
|
Expansion-drum and expansion-coupling. |
left, the studs move up or down in the curved slots, and the diameter of the drum is increased or diminished.
Ex-pan′sion-gear.
（
Steam-engine.) The apparatus by which access of steam to the cylinder is cut off at a given part of the stroke.
A
cut-off.
A
variable cut-off is one which is capable of being adjusted while the engine is in motion, to cut off at any given portion of the stroke, within a given range, as the requirements of the work may indicate.
A
fixed expansion is one arranged to cut off at a determinate part of the stroke.
An
automatic expansion is one which is regulated by the governor, and varies with the amount of power required.
The expansion gear of marine engines generally consists of a graduated
cam on the paddle-shaft, against which a
roller presses and communicates the movement peculiar to the irregular surface of the cam, through a series of rods and levers, to the
expansion-valve situated between the throttle-valve and the slides.
See expansion-valve.
Ex-pan′sion-joint.
1. A stuffing-box joint used when a straight metal pipe, which is exposed to considerable variations of temperature, has no
elbow or curve in its length to enable it to expand without injury.
The end of one portion slips within the other telescopically.
Known as a
faucet-joint.
2. An elastic copper end to an iron pipe to allow it to expand or contract without injury.
3. An attachment of a boiler in its framing to allow the former to expand without affecting the framing.
 |
|
Expansion-valve (side view and front view). |
Ex-pan′sion-valve.
A valve arranged to cut off the connection between the boiler and cylinder at a certain period of the stroke of the piston, in order that the steam may act expansively during the remainder of the stroke.
One form of this apparatus, for marine engines, derives its motion from the crank-shaft of the engine, the valve-spindle being connected by a series of rods and levers with a small brass pulley which presses against the periphery of a graduated cam on the crank-shaft, by which means the steam is “cut off” in the most advantageous manner at any required portion of the stroke.
See cut-off.
Ex′ple-tive-stone.
（
Masonry.) One used for filling a vacuity.
Ex-plor′er.
An apparatus by which the bottom of a body of water is examined, when not beyond a certain depth.
In one form it is called a submarine telescope; in other forms it is a diving-bell, submarine-boat, etc. See armor, submarine; diving-bell; submarine-boat; submarine-telescope.
Ex-plo′sive-ball.
One having a bursting-charge which is ignited on concussion or by time fuse.
See shell.
Ex-plo′sives.
Gunpowder was in use as far back as the twelfth century, and its composition, as shown by old manuscripts, did not differ greatly from the most approved modern manufacture.
See gunpowder.
Berthollet proposed to substitute chlorate of potash for saltpeter in the manufacture of gunpowder.
The explosive force was in this way doubled, but it was found to explode too readily, and, at a trial in loading a mortar, at Essonnes, 1788, the powder exploded when struck by the rammer, blowing mortar and gunners to pieces.
Fulminates of
gold,
silver, and mercury were experimented with in the early part of this century, as substitutes for gunpowder.
Fulminate of mercury is obtained by dissolving mercury in nitric acid and adding a certain proportion of alcohol and saltpeter to the mixture.
It is used extensively in the manufacture of
percussion-caps and cartridges, but none of the fulminates are likely to be used in large quantities, as being too expensive and dangerous.
In an experiment at
Paris, a grain of fulminate of gold was placed on an anvil and exploded by a blow from a sledge, making a dent in both hammer and anvil.
Pyroxyline, or gun-cotton, was discovered by Schoenbein in 1846.
It is prepared by immersing cotton in a mixture of nitric and sulphuric acid for a few minutes, and then washing and drying it. It has been experimented with by several
European nations in connection with fire-arms, but was found to be dangerous, and to rapidly destroy the arms by its excessive energy, and was abandoned by all but the Austrians, who utilized the improvements of
Baron Lenk in gun-cotton, and have several batteries of artillery adapted to use the improved composition.
Abel's English gun-cotton is now used for petards and in mining.
Several compounds based on gun-cotton are used in the arts, as in collodion for photography, surgery, etc.
Nitro-glycerine, which is pure glycerine treated with nitric acid, was discovered by the
Italian chemist Sobrero in 1847, but was very little used until 1863, when it was utilized by Nobel for blasting.
The explosive energy of this compound is given as from four to thirteen times that of rifle powder.
By an explosion of a few cans of this material on the wharf at
Aspinwall in 1866, a considerable portion of the town was destroyed, shipping at some distance in the harbor much damaged, and a number of lives were lost.
An explosion of a storehouse containing some hundreds of pounds of nitro-glycerine took place at
Fairport, Ohio, in 1870, accompanied with much loss of life.
The shock was felt at
Buffalo, 160 miles distant.
Nobel, in 1867, invented a compound called dynamite, which consists of three parts nitroglycerine and one part of porous earth.
Dynamite is supposed to be safe against explosion from concussion or pressure.
See dynamite.
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818]
Dualine differs from dynamite in the employment of sawdust with nitro-glycerine, instead of earth or silica.
See dualin.
Picrate of potash is a yellow salt, extremely explosive, formed from potassium, by the action of picric acid, a product of the distillation of coal-tar.
It was experimented with by the
French War Department to some extent, and was demonstrated to lie between gunpowder and dynamite in its explosive force.
M. Berthelot gives, in
Annales de Chimie et de Physique, a table showing the relative force of explosives.
From this table is deduced the following, expressed in terms of our own standard measurements: —
| Quantity of heat disengaged by one ounce.
| Volume of gas formed. | Relative pressure developed, the pressure of hunting powder being taken as unity. |
| Heat units | Cubic feet. |
| Hunting-powder | 147,871 | 0 216 | 1 |
| Cannon powder | 140.215 | 0225 | 0.986 |
| Mining-powder | 117,467 | 0.173 | 0.633 |
| Mining-powder with excess of niter | 155,472 | 0.111 | 0.540 |
| Powder with nitrate of soda base. | 176,432 | 0.248 | 1.368 |
| Powder with chlorate of potash base | 224,889 | 0.318 | 2.225 |
| Chloride of nitrogen | 72,784 | 0.370 | 0842 |
| Nitro-glycerine | 306,337 | 0.710 | 6.797 |
| Gun-cotton | 145,337 | 0 801 | 3.636 |
| Gun-cotton mixed with nitrate | 228,371 | 0.484 | 3.456 |
| Gun-cotton mixed with chlorate | 327,528 | 0.484 | 4.594 |
| Picric acid | 160,309 | 0.780 | 3.910 |
| Picric acid mixed with nitrate | 223,515 | 0 408 | 3 722 |
| Picric acid mixed with chlorate | 328,909 | 0408 | 4.198 |
| Picric acid mixed with oxide of lead | 49,981 | 0 120 | 0.108 |
| Picric acid mixed with oxide of copper | 94,204 | 0.270 | 0.785 |
| Picric acid mixed with oxide of silver | 60,576 | 0.116 | 0.208 |
| Picric acid mixed with oxide of mercury | 43,762 | 0 212 | 0 288 |
| Picrate of potash | 135,663 | 0 585 | 2.476 |
| Picrate of potash mixed with nitrate | 197,161 | 0.337 | 2.059 |
| Picrate of potash mixed with chlorate | 328,449 | 0.337 | 3.574 |
See —
Blasting.
Blasting-powder.
Dynamite.
Fulminate.
Fuse.
Gun-cotton.
Gunpowder.
Lithofracteur.
Nitrine.
Nitro-glycerine.
Nitroleum.
Percussion-powder.
 |
|
Exsection-apparatus. |
Ex-sec′tion-appara′tus.
（
Surgical.) A splint or support to stiffen and aid an arm from which a section of bone has been removed.
In the example, it has a scapula or saddle-pad which forms a foundation for the other parts, and from this proceed jointed rods and elastic bands, which form auxiliary bones and muscles.
The humerus and the forearm have rigid cases which afford means of attachment for the prosthetic parts, and the cases are held to the arm by flexible aponeurotic bands
f i.
Ex-tend′ed-let′ter.
（
Printing.) One having a face broader than usual with a letter of its hight.
 |
|
Extension-apparatus. |
Ex-ten′sion-appa-ra′tus.
（
Surgical.) An instrument designed to counteract the natural tendency of the muscles to shorten when a limb has been fractured or dislocated.
Ordinarily this is done by means of a weight and pulley attached to an arrangement surrounding the limb immediately above the point of fracture; but in the apparatus shown in
Fig. 1904 this is effected by screwthreaded rods, the lower one of which carries a plate applied beneath the sole of the foot and attached by a stirrup passing over the instep.
It is obvious that this apparatus may be also adapted to dislocations or fractures of the humerus or forearm.
See also counter-extension.
 |
|
Extension-ladders. |
 |
|
Extension-ladders. |
Ex-ten′sion-lad′der.
A ladder having a movable section, which is projected in prolongation of the main
[
819]
section when occasion requires.
A common form is shown in
Fig. 1905, in which the sections of the ladder slide upon each other, and the upper one is extended by chains which pass around rollers and are wound upon a windlass journaled to the lower section.
Another form has a standing base part.
The ladder is formed of jointed sections, which may be folded together or arranged as a self-supporting ladder.
Some ladders are mounted on trucks to be used in emergencies.
See fire-escape.
Some of the
Roman scaling-ladders were made in sections and put together to form a large ladder.
Others of their ladders might be elevated with a man on the top for reconnoitering.
Ex-te′ri-or-screw.
One cut upon the outside of a stem or mandrel, in contradistinction to one whose thread is cut on an interior or hollow surface.
Ex-te′ri-or-slope.
（
Fortification.) The slope of a parapet towards the country.
It is at the foot of the
superior slope, and forms the lower portion of the rampart above the
escarp, or the
berm, if there be one.
See parapet.
Ex-tin′guish-er.
A little cone placed on top of a burning candle to extinguish the light.
Extinguishers were also formerly attached to the railings of city houses to enable the link-boys to dout their torches.
Some lamps have attachments which may be made to clasp the exposed portion of the wick and extinguish the flame.
Ex-tract′or.
（
Surgical.) An instrument for removing substances from the body.
See bulletforceps, etc.
Ex′tra-dos.
The exterior curve of an arch, measured on the top of the voussoirs; as opposed to the
soffit or
intrados.
Eye.
An opening through an object; as, —
1. (
Nautical.)
a. A circular loop in a shroud or rope.
A worked circle or grommet in a hank, rope, or sail.
b. The loop of a block-strap.
c. The hole in the shank of an anchor to receive the ring.
2. (
Milling.) The hole in a runner stone through which the grain passes to be ground.
3. The hole through the center of a wheel, to be occupied by the axle, axis, or shaft.
4. The eye of a crank; a hole bored to receive the shaft.
5. A metallic loop on the end of a trace, to go over the pin or hook on the end of a single-tree.
A
cock-eye.
6. (
Architecture.)
a. The circular aperture in the top of a dome or cupola.
b. The circle in the center of a volute scroll.
c. A circular or oval window.
7. The hole in the head of an eye-bolt.
8. The center of a target.
A bull's-eye.
9. The thread-hole in a needle.
10. The loop in which the hook of a dress catches.
 |
|
Artificial eye. |
Eye, Arti-fi′cial.
1. A shell or segment of a hollow sphere, usually made of enamel, and so inserted as to present the appearance of the natural eye.
Artificial eyes made of glass are found in ancient
Egypt.
In the
Abbott Museum of Egyptian Antiquities, New York, are several wooden cats with glass eyes.
One of them is but a shell, and contains the mummy of a cat. They are from the cat-tombs of Sakkarah.
In the example (
Fig. 1907), the caruncular portion of the ocular orbit has unguinal depressions on each side of the nasal extremity, so as to establish harmony between the circumference of the prosthetic shell and the organic sinuosities when used on either side.
2. (
Nautical.) An eye worked into the end of rope, as a substitute for a spliced eye.
Eye-bolt.
A bolt having an eye or loop at one end for the reception of a ring, hook, or rope, as may be required.
The insertion of a closed ring into the eye converts it into a ring-bolt.
 |
|
Eye-cups. |
Eye-cup.
A cup for washing the eyeball.
Its lip is held firmly against the open lid, and the eye-wash dashed against the ball, or forced against it by compressing the reservoir, as in the example.
The device shown is also applicable to the eyeball for the purpose of preventing myopia by preserving the convexity of the cornea; the bag
c, being partially exhausted, is allowed to expand after the edges of the cups are seated upon the eye-balls.
Eye-ex′tir-pator.
A surgical instrument for removing the eye.
Putting out the eyes has long been a common
Oriental punishment.
The eyes of Zedekiah were put out by Nebuchadnezzar.
Xenophon states that in the time of the younger
Cyrus the practice was so common that the blinded men were a common spectacle on the highways.
The
Kurds and
Turkestan hordes yet blind their aged prisoners.
 |
|
Eye-glasses. |
Eye-glass.
1. (
Optics.) The glass nearest to the eye of those forming the combination eye-piece of a telescope or microscope.
The other
glass, nearer to the object-glass, is called the
field-glass. See negative eye-piece.
2. A pair of glasses to aid the sight; usually worn by clasping the bridge of the nose.
They are of various shapes,
a b c d. The watchmaker's or engraver's eye-glass
e has a horn frame and a single lens.
Its flaring edge is retained within the ocular orbit by the muscular contraction of the eyelids.
Eye-head′ed bolt.
A form of bolt having an eye at the head end. It is intended for securing together two objects at right angles, — as a gland to a stuffing-box, etc. See bolt.
Eye-in′stru-ments.
| Operative. | Ectropium. |
| Cataract-knife. | Entropium. |
| Cataract-needle. | Entropium-forceps. |
| Couching-instrument. | Eye-cup. |
[
820]
| Eye-extirpator. | Iridioscope. |
| Eye-forceps. | Opsiometer. |
| Eyelid-dilator. | Ophthalmometer. |
| Eye-protector. | Ophthalmoscope. |
| Eye-speculum. | Ophthalmostate. |
| Eye-syringe. | Prosthetic. |
| Iriankistrium. | Eye.
Artificial |
| Iridectomy-instrument. | Pupil.
Artificial |
| Keratome. |
| Lachrymal-duct dilator. | Optical. |
| Pterygium. | Eye-glass. |
| Strabismus-forceps. | Goggles. |
| Strabismus-scissors. | Shades. |
| Spectacles. |
| Examinative. | See optical instruments. |
| Auto-opthalmoscope. |
Eye-lens.
That one of the four lenses in an eye-piece which is nearest to the eye. The
eye-piece.
Eye′let.
A short metallic tube whose ends are flanged over against the surfaces of the object in which the said tube is inserted.
It is used as a bushing or reinforce for holes to prevent the tearing of the perforated edge of the fabric or material by the lacing.
Eyelets are made from strips of metal by a cutting and punching operation, or punching and shaping.
In the example, the strip of eyelet metal is forwarded by the grasping jaws of a reciprocating lever, between the dies which form frusto-conical recesses, preliminary to annealing and punching.
 |
|
Eyelet-making machine. |
Eyelet-eer′.
A stabbing instrument of the work-table, to pierce eyelet-holes.
A
stiletto.
 |
|
Eyeleting-machine. |
Eye′let-ing-machine′.
A machine for attaching eyelets to garments or other objects.
The guide-pin within the punch takes the eyelets from the mouth of the feeding-chute
B, said pin being subjected to the action of a spring having a tendency to force it out of the punch.
When pushed in, the guide-pin is retained by a springcatch which is automatically released as often as the punch reaches its highest position.
The friction-spring retains the eyelets on the guide-pin till the punch forces them off. The anvil
I has a projecting point, and is surrounded by an elastic tubular bed, so that the material to be eyeleted, on being forced over the point, is pierced and then supported by the elastic bed, which offers sufficient resistance to permit the eyelet to be forced through the hole.
Eye′let-punch.
A device used at the desk for attaching papers together by eyeleting.
It has usually a hollow punch for making a hole, and a diepunch to upset the flange of the eyelet.
Eye′let-set′ting ma-chine′.
See Eyeletingmachine.
Eye-piece.
（
Optics.) An
eye-piece, or
power, as it is sometimes called, is the lens or combination of lenses used in microscopes or telescopes to examine the aerial image formed at the focus of the objectglass. — Brande.
Eye-pieces may be, —
1.
Positive (Ramsdens).
2.
Negative (
Huyghenian).
3.
Diagonal.
4.
Solar (
Dawes).
5.
Terrestrial or
erecting.
Eye-piece mi-crom′e-ter.
A graduated slip of glass introduced through slits in the eye-piece tube, so as to occupy the center of the field.
Adapted by
Jackson.
Eye-rim.
A circular single eye-glass, adapted to be held to its place by the contraction of the orbital muscles.
 |
|
Eye-speculum. |
Eye-spec′u-lum.
（
Surgical.) An instrument for dilating the eyelids, to expose the exterior portions of the eye and its adjuncts.
Eye-splice.
（
Nautical.) A splice made by turning the end of a rope back on itself and splicing the end to the standing part, leaving a loop.
