PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 449 



with equal facility. In ovdev to accomplish this, the driving wheels are 

 fitted with a mechanical arrangement which acts like a cat's claw, in seizing 

 or taking firm hold of the ground. Tliese talons are projected through the 

 rim of the wheel, and are withdrawn with a feathering action like that of 

 a paddle-wheel at the moment they act as an obstruction; they simulate, 

 in fact, the sheathing action of the cat's claw, clearing themselves, at every 

 rotation of the wheel, of tlie clogging soil. The engine is capable of 

 ascending gradients as steep as one in six, and it has several times been 

 seen, to the astonishment of the townspeople, conveying a 68-pounder gun, 

 weighing 112 cwt., down the Plumstead road, over the steep acclivity of 

 Burrage hill, and returning by the descent of Sandy hill to the Arsenal ; a 

 feat which, it is needless to say, horses could not have accomplished. On 

 Woolwich Common, moreover, it manceuvres with three of these ponderous 

 68-pounders with an astonishing facility. 

 ; "peculiarities. 



" The wheels of the traction engine are so broad that they do no damage 

 to the ordinary road, and they run without sinking in marshy land and on 

 loose ground, where ordinary wagons would sink beyond reclaim. The 

 ordinary pace of the engine, when carrying a load over broken ground, is 

 about three miles an hour, but it will run at the rate of ten miles an hour; 

 and it has been proved capable of drawing, over a good road, as. great a 

 weight as a hundred tons. 



"The speed and power of traction, and the low cost at which it works — 

 the expense for the coke not being more than two-and-sixpence per 

 day — point to the great adaptability of the traction engine for lines of 

 metropolitan tramway, or to lines running between towns incapable of 

 supporting a. railway with its expensive rolling stock. This engine moves 

 so noiselessly, that if one were constructed specially to run in our streets no 

 horses would be frightened by it, and it maybe easily arranged to avoid the 

 escape of steam altogether. However, the extraordinary handiness and 

 compactness of this new power, the ability to turn the power to any kind 

 of work, and the ease with which it is guided by the aid of the steerage- 

 wheel, will, without any measure of doubt, render her the indispensable 

 companion of man wherever great works are in progress, or mighty 

 engines have to be lifted and conveyed from place to place in the ordinary 

 course of the day's work. To the arsenal and dockyard, the engine now 

 at work there is invaluable; and the cost has been so much less than horse 

 power that two teams have already been dispensed with. In the old days 

 of horse traction, it was a common thing to see skilled hands, earning five 

 shillings a-day, employed at mere laborers' work in certain emergencies, 

 for want of a full suppl}'^ of traction power; now all this is saved by the 

 ever-ready power of this manageable monster, which promises to become 

 the common drudge of man in every field of exertion where gigaTitic 

 powers have to be called into action." 



The Chairman. — I noticed an article in the English Naval Gazette, which 

 candidly admits that the Americans excel all other nations in the perfec- 

 tion and manufacture of implements of warfare. Mr. Parrott, who has de- 

 voted considerable attention to the construction of heavy guns, makes the 

 [Am. Inst.] D* 



