CATALOGUE OF THE MECHANICAL ENGINEERING COLLECTION. 57 



to a cross shaft. The forward end of the horizMiital extension of 

 each lever is attached to the wrists of the crank shafts. These crank 

 shafts are aligned but independent, and in place of constructing each of 

 them in one continuous angular piece it is formed in two parts, which 

 are rigidly connected by an interposed annulus. The wrists of these 

 two parts are attached to the annulus at opposite points on its side 

 and the forward end of the walking legs are also attached at the same 

 points, the revolution of the crank shaft and its annulus imparting a 

 complex movement to the walking legs. This movement is not 

 unlike that of the hind legs of a cow. 



FIG. 23. PEAUL STEAM TRACTOR, 1879. 



When in operation the feet of each pair of legs will be alternately 

 lifted from the ground and carried forward and again brought 

 down, thus describing an approximately elliptical figure, while the 

 legs as a whole will have a forward and backward movement, alter- 

 nately rising and falling in consequence of the overhead links vibrat- 

 ing in the arc of a circle. The vertical extension of the legs is nearly 

 aligned with the links overhead and the feet move in nearly a hori- 

 zontal plane, so that the rear part of the body of the engine is 

 carried smoothly or has a scarceh^ perceptible rising and falling 

 movement during the time the legs are making their backward 

 movement. A vertical boiler and the engine are carried on the rear 



