Page:The Kinematics of Machinery.djvu/622

 600 NOTES.

breaking some essential part of them, very much as we spike cannon. In 2 Sam. viii. 4, we have : " And David took from him a thousand and seven hundred horsemen, and twenty thousand footmen : and David houghed [ren- dered useless] all the chariots, and reserved of them an hundred chariots ;" also Joshua xi. 6 . . . " Thou shalt hough their horses and burn their chariots with fire . . . (v. 9) Joshua . . . houghed their Corses and burnt their chariots with fire." That the Jews had long known wheeled vehicles is evident from a passage in Numbers (vi. ; 3 8), where six (wooden) wagons, each drawn by two oxen, are spoken of. The wheels of Solomon's laver carriages (about 1000 B.C.) were cast of bronze (1 Kings vi. 33), " their axle-trees and their naves and their felloes and their spokes were all molten."

28 (p. 209.) The museum in Toulouse contains two remarkably well preserved antique bronze chariot-wheels of 54 cm. diameter, with naves 40 cm. long and 7 cm. diameter ; casts of them are in the Romano -Germanic museum at Mainz. These wheels have five round spokes and deeply-recessed felloes ; in the latter the rivets for fastening on the wooden rims still remain. The Esterhazy collection at Vienna, and the national museum at Pesth contain similar excel- lent specimens ; an existing Egyptian carriage- wheel of wood is described and illustrated in Wilkinson, The Ancient Egyptian, vol. i. p. 383.

- p (P. 209.) In the gradual development of the chariot-wheel in construc- tive form, the tire plays a very important part, It was evidently the metal rim which first made the wheel durable when used for quick motion along heavy roads. It was long, however, before the iron tire made in one piece was reached. Homer mentions in his celebrated description of the chariot of Juno, tires of copper (Iliad, v. 722, et seq.) :

" Quickly Hebe fixed on the chariot the rounded wheels Of copper, eight-spoked, around an iron axle ; Their felloes, indeed, were of gold, imperishable, but around Tires of copper were firmly fitted, a wonder to behold."

The last words show that there must have been great difficulty in completing the " firmly-fitted " tires (in segments ?). That these were made of copper does not exclude the possibility that iron rims were also in use. Assyrian and ancient Persian relievos show chariots of many forms, most of them with . smooth tires, scarcely distinguishable from the rest

jJ of the wheel. A few wheels are specially remark>ble

us showing rings of little projections (Fig. 447), like strings of beads all round the tire. Prof. Lindenschmidt, of Mainz, who called my attention to this peculiarity, solved the riddle at once. The projections are intended for the heads of nails. The whole wheel is covered with nails, driven into the wooden rim in close rows, their heads overlapping each other like scales. Among FIG. 447. the discoveries in ancient burial-places in South Ger-

many there are not a few iron tires about a metre diameter. They are alwa}*s foundinpairs, and are evidently the remains (after the rottingawayof the wood), of the chariot wheels of the dead warrior, which had been buried along with him. These tires are covered with radial spikes on the inside, and their outer surfaces show the scale-like overlappings just mentioned. Close inspection

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