steel in preference to copper may be credited to Mr. Perkins and the engraver Warren.
Warren annealed his plates at a high temperature in earthen boxes packed with pounded oyster-shells.
The practice in the Bank of England, as modified by Oldham, is to anneal at one time four east-iron boxes, each containing from three to six steel plates, surrounded on all sides with fine charcoal, mixed with an equal quantity of chalk, and driven in hard.
The reverberatory furnace employed has a cir repaired, the parts brought up sharply by re-rolling under the transferroller.
Danger of warping is also avoided.
Though belonging to the hardening, and not to the anncaling process, it may here be mentioned, to complete the subject, that Oldham, Jr., has introduced a plan for precipitating the plates instantly into water, so as to prevent even an instantaneous exposure to the air; thus avoiding scale, or even a rough discoloration.
Many recipes are extant in the trade
The wires when inserted are slightly riveted at the ends.
Chains intended to catch on pins or projections on the periphery of a wheel are made two and two, as in the other figure, leaving an opening which slips over the cog.
Mr. Oldham, the engineer to the Bank of England, contrived a curved link-chain f f, adapted to work in connection with a cog-wheel g, with epicycloidal teeth.
Chains for watches, timepieces, and small machinery are too minute to be made as the ordinaryew's-harp-shackle.
Clasp.Joint (varieties, see joint).
Claw for suspending tackle.Joint-coupling.
onsists of disks or wheels decimally numbered on their peripheries, the whole mounted on one axle, upon which they turn freely, acting upon each other in serial order, as explained under arithmometer. The first wheel of the series containing the units is moved one figure between each impact, and when the units are exhausted the tens come into action, and act in coincidence with the units, which continue their action.
So on of the 100s, 1,000s, etc.
Bramah's numbering-machine, improved by Oldham, had 5 brass circles with studs carrying the numerals, so as to be able to number up to 99,999.
The bank-note was presented on a table above, and the tympan brought down upon it, forcing the paper against the numbered studs, which were presented through openings in the bed. After each impression the first wheel of the train was rotated one spoke, bringing the next unit into presentation.
The unitwheel acted upon the 10-wheel as soon as the number 9 was reached and printed; the 10-wheel act
The reamer is introduced into the bore to true it; the drill fails to make a smooth hole, and the reamer is about circular in its form, giving a perfect shape, and fitting the bore to receive the tube.
The pipe-tongs is adapted to grasp the drill-rod or tube while a new hitch is being taken in withdrawing or introducing either.
The presence of oil in springs has been noticed from time immemorial, and the rock-oil, Seneca oil,o silver flexible tubes, one b for the uterus and the other c for the male urethra.
The instrument forms a porte-caustic.
d is a platinum spoon for melting caustic.
A sliding coupling for parallel shafts, invented by Oldham.
a a are the axes of two shafts; b b, two cross-heads on their ends; c c, bars sliding in grooves in the cross-heads: the bars are fixed together at their midlengths so as to form a cross, the middle point d of which revolves upon the dotted cir
s in the radial arms.
On the axis of each paddle is an arm from which a rod proceeds to an eccentric on the paddle-wheel shaft.
The effect is to keep the floats vertical at all points of their revolution.
Machinery of Fulton's steamboat Clermont (1807).
In Galloway's patent of 1829 the revolution of the wheel causes an eccentric collar to rotate by the action of arms, and the radius rods cause each paddle to oscillate on its axis so as to enter and leave the water obliquely.
In Oldham's improvement in 1827, the angle of the paddles is constantly varying, being vertical only at the point of greatest submergence, and horizontal at the point of greatest elevation.
The change of position is accomplished by the oscillation of the axis of the float, by means of rods, cranks, and an eccentric wheel on the paddle-shaft.
b. Dawson's feathering paddle-wheel (A, Fig. 3476), 1814, has floats attached to radial rods which rotate on their axes so as to enter and leave the water obl