gage is therefore sometimes placed below the body of the coach ; light parcels 

 of large bulk may be placed on the top with impunity. 



When the centre of gravity of a carriage is much elevated, there is consid- 

 erable danger of overthrow, if a corner be turned sharply and with a rapid pace ; 

 for the centrifugal force then acting on the centre of gravity will easily raise 

 it through the small height which is necessary to turn the carriage over the 

 external wheels. 



Fig. 25. 



The same wagon will have greater stability when loaded with a heavy sub- 

 stance which occupies a small space, such as metal, than when it carries the 

 same weight of a lighter substance, such as hay ; because the centre of gravity 

 in the latter case will be much more elevated. 



If a large table be placed upon a single leg in its centre, it will be imprac- 

 ticable to make it stand firm ; but if the pillar on which it rests terminate in a 

 tripod, it will have the same stability as if it had three legs attached to the 

 points directly over the places where the feet of the tripod rest. 



When a solid body is supported by more points than one, it is not necessary 

 for its stability that the line of direction should fall on one of those points. 

 If there be only two points of support, the line of direction must fall between 

 them. The body is in this case supported as effectually as if it rested on an 

 edge coinciding with a straight line drawn from one point of support to the 



