LOCOMOTIVE ENGINE. 



455 



there is the leverage of the whole length of the axle to keep them upright, but when 

 they are loose there is only the hold of the thickness of the nave. 



The construction of the wheels is shewn in figs. 32, 33, 34, and 35, to a scale of an 



Fia. 32. FIG. 34. 



FIG. 35. FIG. 3& 



inch and a half to a foot, or double the size of the engravings. Fig. 32 is a section 

 through the centre of one of the small wheels, and fig. 33, is a cross section through 



