154 EQUILIBRIUM OF FLUIDS.^ 



Suppose the heavy body to weigh seven out of water and three in water, its 

 loss will be four ; and suppose the light body weighs '65 out, and '27 in the 

 water, its loss will be '38 ; by subtracting '38 from 3*00, we have 2'62. 



Therefore, as 2'62, the last remainder, is to '65, the weight of light body in 

 air, so is TOO, the specific gravity of water, to '24, the specific gravity of the 

 body. 



When the specific gravity of a fluid is required, take a piece of some sub- 

 stance of known specific gravity, weigh it both in and out of the fluid, and 

 find the loss of weight by taking the difference of these two ; then say, 



As the whole or absolute weight, is to the loss of weight, so is the specific 

 gravity of the solid, to the specific gravity of the fluid. 



Take 2 '31 as the specific gravity of the known substance, suppose its 

 weight out of the fluid to be five, and in the fluid 3'2, the loss will be 1'8. 



Therefore, as 5, the whole weight, is to 1*8, the loss, so is 2'31, the known 

 specific gravity, to '83, the required specific gravity of the fluid. 



