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Knight's Mechanical Encyclopedia (ed. Knight) 59 1 Browse Search
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e having a bulb near the small end, composed of two hemispheres in which the moisture from the breath is condensed, and which may be unscrewed for convenience of carrying in the pocket. c. Gahn's blow-pipe made in four separable parts. d. Wollaston's blow-pipe ready for use. e. Wollaston's blow-pipe with its lower end and beak slid in for carriage in the pocket. f. Dr. Black's blow-pipe. The smaller end is the mouth-piece, and the larger condenses the moisture. While the use of Wollaston's blow-pipe with its lower end and beak slid in for carriage in the pocket. f. Dr. Black's blow-pipe. The smaller end is the mouth-piece, and the larger condenses the moisture. While the use of the blow-pipe dates from distant antiquity, yet its use in mineralogy, in determining the nature of the metals in ores, dates from Antony von Suab in 1738, and Cronstedt, 20 years later. The subject may be satisfactorily pursued in Plattner on the blow-pipe, and by consulting a late work, System of Instruction in the practical Use of the Blow-pipe. The reducing flame is produced by blowing the flame of the lamp aside by a weak current of air impinging on the outer surface, the flame being u
. Cam′e-ra-lu′ci-da. Founded upon the invention of Baptista Porta (1589), by Dr. Hooke, about 1674. Improved by Wollaston, 1805. Phil. Trans., Vol. XXXVIII. p. 741. It consists of a glass prism a b c d, by means of which rays of light ary b and c till it assumes the direction c E, at which latter point is the eye of the observer. As a contrivance of Dr. Wollaston, for the purpose of delineating a microscopic object, it consists of a prism fitted on the front of the eye-piece of em connecting the hemispheres has a diameter equal to 1/5 of the focal length of the lens. This lens was invented by Dr. Wollaston, and called by him the periscopic lens; he made it by cementing together by their plane faces two hemispherical lense Cryophorus. Cry-oph′o-rus. An instrument to illustrate the process of freezing by evaporation. Invented by Dr. Wollaston. It consists of two bulbs and a connecting tube, air being expelled from the interior by heating the body of water<
ol gradually by the rotation of the axial screw. Diffe-ren′tial Gear′ing. A form of gearing first introduced by Dr. Wollaston in his trochiometer, for counting the turns of a carriage-wheel, in which two cog-wheels of varying sizes are made to (Printing.) A roller to dip ink from the fountain. Dip-sec′tor. A reflecting-instrument. One was invented by Dr. Wollaston, and one by Troughton. It is used for ascertaining the true dip of the horizon; the principle is similar to the sextis used in contradistinction to the single-fluid batteries, such as the original Volta, the Cruikshank, Babbington, and Wollaston. The gravity-battery is a double-fluid battery in which the porous cup is dispensed with, the difference in the specinder steam-engine; duplex steam-engine. Doub′let. 1. (Optics.) An arrangement of lenses in pairs, invented by Wollaston. It consists of two plano-convex lenses having their focal lengths in the proportion of one to three, or nearly so,
line form of the diamond is octohedral, and the faces are usually convex. Upon this latter peculiarity, according to Dr. Wollaston, its efficiency depends, the rounded edge slightly indenting the glass and then slightly separating its particles, foere followed by plates of gold attached to the tortoise-shell nibs. Doughty's pens were of gold with ruby points. Wollaston's pens were of two flat strips of gold tipped with rhodium. In 1851, the Birmingham Exhibition in London showed goldickness of the silver at first and shares all its mutations in the drawing, retaining the same relative thickness. Dr. Wollaston, a man of extraordinary tact in delicate experiments, made the finest wire on record. He bored out a rod of silver, essively in line with the directions of the two sides of the crystal, and the difference in the degrees is observed. Wollaston's reflecting goniometer consists of a graduated circle provided with a vernier reading to minutes. The axis of the cir
ders, consisting of several narrow cinctures cut into the shaft at the base of the echinus. Hyp-som′e-ter. An instrument for measuring hights by observing differences in barometric pressures at different altitudes. Notably, an instrument for determining altitudes by observation of the boilingpoints of water. It has a watervessel, lamp, and thermometer. The example shows the instrument and the case in which it is packed for transportation on the back of a tourist or attendant. Wollaston's apparatus for in measuring hights by the temperature of boiling water has a mercurial thermometer with a very large bulb and a stem, which has a length of one inch for every degree of the scale. This is read by a vernier to thousandths. It is found that a difference of barometric pressure of 0.589 inches is equivalent to 1° in the boiling-point, or 530 feet of ascent at moderate elevations. Tables have been constructed for use with the apparatus, showing the precise elevation corres
a obtained a solid globule of glass is formed, which is said to be well adapted to microscopic purposes. A cylindrical lens has a body formed of a segment of a cylinder, or of two such segments united by their bases. A Stanhope lens. A diamond lens is made from a diamond whose high refractive power is supposed to render it specially suitable for an eye-glass. Diamond lenses were made by Andrew Pritchard in 1824. A doublet is an arrangement of two plano-convex lenses, invented by Wollaston, as shown at a a; b is a diaphragm. c d is Herschel's doublet. A triplet m is an arrangement of three plano-convex lenses in a microscope. Invented by Holland. n is also a threefold arrangement of lenses, any two or all of which may be used in combination, according to the power desired. Eye-glass; the lens nearest to the eye in a simple arrangement, and the one nearest to the eye of the glasses forming the combination eye-piece of a telescope or microscope. Compound eye-glas
2913Cronstedt1751Ger. Kupfernickel. Osmium.Os.99.6198.821.43,992.0306Mag.10Tennant1804Gr. Osme (odor). Palladium.Pd.53.3106.4711.83,632.05931/1000Mag.85628018Wollaston1803The goddess and asteroid Pallas. PlatinumPt.98.7197.121.53,992.03241/1131Mag.9435603818Sp. dim. of Plata (silver). PotassiumK. Potash. RhodiumRo.52.2104.312.14,352.0580Diamg.14Wollaston1804Gr. Rhodon (a rose). SilverAg.108107.9310.531,832.05701/524Diamg.922400100100 SodiumNa.2323.040.972194.2934Diamg.636Davy1807Lat. Salsola (soda). StrontiumSr.4487.252.547Davy1808Strontian in Scotland. TelluriumTe.64128.36.25752Muller1782Gr. Tellus (the earthr. A filament of silk, a fiber of spun-glass, of melted sealing-wax, of asbestos, or a minute crystal of mezzolite, were successively suggested and employed. Wollaston adopted a platinum wire, drawn to extreme tenuity by inclosing it in a plug of silver, afterward removed by acid; this is illuminated by a ray of light which pas
ed way. Pal-ita. A light shovel. A trowel. Pal-ladi-um. Equivalent, 53.3; symbol, Pd.; specific gravity, 11.8; difficult to fuse. Discovered by Dr. Wollaston in 1803. It is a white, malleable, ductile, hard metal; fusible with the oxyhydrogen blowpipe. The alloy of palladium and silver is eminently suitable fo (Surgical.) A device for loosening and raising the periosteum out of the way of an instrument in making exsections, etc. Per′i-scop′ic lens. (Optics.) Dr. Wollaston's periscopic lens for microscopes had two plano-convex lenses ground to the same radius, and between their plane surfaces a thin plate of metal with a circularitter, in 1801, proved the existence of dark rays beyond the violet end of the visible spectrum, by the power they possessed of blackening chloride or silver. Wollaston also published some experiments on the changes which light produced in gum-guaiacum, corroborating Ritter's views as to the activity of invisible rays. Wedgw
, that made it, cannot get one to do it. So I got Cocker [the celebrated arithmetician, Ob. 1679], the famous writing master, to do it, and I set an hour by him, to see him design it all. — Pepys's Diary, 1664. Rules. Some rules have a slider in one leg; in Gunter's scale this is graduated and engraved with figures, enabling various simple computations to be made mechanically. When Dalton (who died in 1844, aet. 78) made known his discovery of the theory of chemical equivalents, Dr. Wollaston invented a sliding rule, on the principle of Gunter's, for facilitating chemical calculations; it was employed for determining the chemical equivalence of compound bodies, and the proportion of one substance necessary to decompose another. Pattern-makers use a rule whose divisions are made a certain per cent longer than standard measure. Iron castings shrink in cooling about 1 per cent, or 1/8 of an inch to a foot. The patterns therefore require to be made proportionately larger. B
ctor (which generally forms part of a case of mathematical instruments); Gunter's scale, and Dr. Wollaston's scale of chemical equivalents. See list under calculating and measuring instruments. s the first of this class. Cruikshank was the first to submerge the elements. Babbington and Wollaston had also submerged elements. See gravity-battery; Cal-Laud-battery. The term is in contraave, double convex, periscopic, pebble. Periscopic glasses were invented by the eccentric Dr. Wollaston. The glasses are concavo-convex, and facilitate oblique vision. Spectacles are said to b at a point far beyond the visible part of the spectrum. At the beginning of this century Dr. Wollaston, in repeating the Newtonian experiment, admitted a beam of light through a very narrow slit g is an application of the art of electroplating which originated with Volta, Cruickshank, and Wollaston, about 1800-1801. In 1838, Spencer, of London, made casts of coins and cast in intaglio from
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