CENTRE OF GRAVITY. EXRERIMENTS. 



35 



Body sing:ulaiiy balanced by 

 lead knobs. 



cause the cylinder to roll up an inclined plane, when 

 placed as shown by the lower figure on the preceding en- 

 graving, until it makes half a revolu- 

 tion and reaches the place of the up- 

 per figure, when it will remain sta- 

 tionary. If a curved body, as shown 

 in fig. 19, be loaded heavily at its 

 ends, it will rest on the stand, and 

 present a singular appearance by not 

 falling, the centre of gravity lying 

 between the two heavy portions on 

 the end of the stand. A light stick 

 of some length may be made to stand 

 on the end of the finger, by sticking 

 in two penknives, so as to bring the 

 centre of gravity as low as the finger-end (fig. 20). 

 If any body, of whatever shape, be suspended by a 

 hook or loop at its top, it will 

 necessarily hang so that the 

 centre of gravity shall be di- 

 rectly under the hook. In this 

 way the centre in any substance, 

 no matter how irregular its shape 

 may be, is ascertained. Sup- 

 pose, for instance, we have the 

 irregular plate or board shown 

 in the annexed Fig- 21. 



figure (fig. 21) : 

 first hang it by 

 the hook a, andflf{ 

 the centre of 

 gravity Avill be 

 in 



the dotted line a b. Then hang it by the hook c, and it 

 will be somewhere in the line c d. Now the point e, where 

 they cross each other, is the only point in both, conse- 



Centre of gravity maintained hi) ttno 



penknives. somcwhere 



