SPECIFIC GRAVITY. 



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on it, and when it weighs less than air, it will rise in it ; 

 thus, iron will float in melted lead, gas will rise in the air, 

 and wood will float on water. 



The weight of a cubic foot of water being 1000 ounces 

 avoirdupois, it has been adopted as the standard of specific 

 gravities. Hence the specific gravity of a body or substance 

 is the proportion its weight bears to this standard. 



To find the specific gravity of a liody. 



RULE. Weigh it first in air and then in water, and take 

 the difference of these weights ; then as the difference is to 

 the weight in air, so is 1000 to the specific gravity of the 

 body. 



EXAMPLE. What is the specific gravity of a stone weigh- 

 ing 20 Ibs., but in water only 15 Ibs. ? 



SOLUTION. 20 15=5 difference; then 5 : 20:: 1000 : 

 4000. Ans. 



When the body is lighter than water. 



