[ PARALLEL FORCES AND CENTRE OF GRAVITY 83 



as before and again make a mark in continuation of the string. 

 The two chalk marks intersect at a point marked G, Fig 35. 

 Untie and do the same with another string, the third line 



FIG. 34. Figures for the Determination of Centres of Gravity. 



passes through the intersection of the first two. Obtain a 

 similar point for each of the other plates. Also determine in 



Fin. 35. The Determination of Centre of Gravity. 



the .same way a .similar point for irregular plates of wood, zinc 

 or cardboard. 



EXPT. 67. Balance the pieces of wood, zinc, or cardboard, 

 one after the other, upon a pointed upright, at the intersection 



G 2 



