CH. IX 



CENTRE OF GRAVITY 



135 



Fig. 67. 



at which the coach will tip over, or, what is the same 

 thing, the elevation of the wheel on the higher side 

 which will cause it to balance. 



It will be evident by comparing diagrams A and 

 B in Fig. 67, that the lower the centre of gravity 

 for the same wheel- 

 base, the higher the 

 wheel must be raised 

 to cause a tip-over ; 

 whence the importance 

 of keeping the centre 

 of gravity low. 



To be strictly accurate, we must say that we have 

 thus far only found a horizontal line passing 

 through the body of the coach, in which line the 

 centre of gravity is somewhere situated. If we 

 wish to know the position of the point, we must go 

 through the same operation for the side of the 

 coach, but since a coach never turns over forward 

 or backward, where the centre of gravity is situated 

 lengthwise is of small moment, and the relative 

 weights on the front and hind wheels will show it 

 with sufficient accuracy. 



Plate XXIII. shows the method of tipping a coach 

 for the purpose of finding the position of its centre 

 of gravity. A drag weighing, without any load, 2300 

 pounds, was tipped until it exactly balanced on the 

 wheels of one side. The vertical line passing 

 through the point of support, intersected the centre 

 line of the coach at the point marked 2300 (which 



