AMERICAN IKSTITUTE. 583 



the middle of the axle, and two, of half size, acting simultane- 

 ously on the wheels outside. To prevent pitching he placed 

 tlie guide-bars near the centre of gravity of the suspended mass. 

 There would have been no rocking, and but slight pitching, in 

 this arrangement; but if the springs were easy there would have 

 been a lift of the whole suspended i^ass — enough to waste con- 

 siderable power, and to wear the springs. The plan was not 

 successlul, on trial, and the conception of it, by such a talented 

 engineer, only proves his sense of the greatness of the evil he 

 sought to remedy. 



Hai-tworth, who at that time altered the vertical cylinder, 

 w^hich pitched and rocked excessively if there w^ere any springs 

 at all, applied a crank-shaft working in fixed bearings, from 

 which he transmitted the power by parallel rods to the wiieels, 

 whose axles woried in jaws in the usual way. Stephenson and 

 Sinclair have since tried the crank-shaft, with horizontal cylin- 

 ders, and transmitted the power to the wheels in the same way. 

 But the ar-rangement has not been adopted ; nor is it possible to 

 use any springs with it, without danger of breaking off" the crank 

 pins, or other parts of the connections ; for if the axle is much 

 out of its normal level at the time the crank pin is at the dead 

 point, the parallel rod cannot reach it without straining. The 

 jaw might be curved, which would meet this objection ; but in 

 that case there would be other difficulties. 



I claim to have solved the problem, perfectly, by using radius 

 rods, instead of jaws, to keep the axle at a constant distance from 

 the crank-shaft; and by transmitting the power from the crank- 

 shaft to the axle by means of parallel rods, as was done by Hart- 

 worth and the others. This arrangement, of course, obviates 

 the tendency to rock and pitch; and it also obviates the friction 

 of the axle box against the jaw, which causes waste of power and 

 considerable wear, and obstructs the action of the springs. The 

 pressure on a piston 16 inches diameter is sometimes more than 

 12 tons; and when the oil has worked out, and dust has worked 

 into the jaw, the friction may be a sixth of this, or 2 tons, which 

 must be slid up or down by power drawn from the engine, or 

 must cause a greater disturbance of the suspended parts than 

 would occur if there were no such resistance to the free action 

 of the springs. 



The question is often asked, " Why has not the locomotive 

 been applied on the common road, since it is known that it can 

 draw eighty times its own weight, at ten miles per hour, on rails, 



