THE PRINCIPLE OF AECHIMEDES. 



189 



fig. 136. The weight thus removed from the left- 

 hand scale-pan, or that placed in the right-hand one, 

 represents the weight lost by the immersed body : if 



FIG. 136 (^ real size). 



the displaced water be now weighed, its weight will be 

 found to be precisely equal to that loss. 



The principle of Archimedes furnishes a method of 

 determining the specific gravity of bodies. For this is 

 obtained by dividing the weight of a body by the weight 

 of a quantity of water occupying the same volume as 

 the body ; but the weight of the volume of water dis- 

 placed by an immersed body is precisely equal to the 

 weight lost by the body, hence the specific gravity of a 

 body may be found by weighing it in air and in water, 

 and dividing; its weight in air by the weight which the 

 body loses, when immersed in water. In order to find the 

 specific gravity of a body, shot or sand is first placed_in 



