MISCELLANEOUS PROBLEMS. 525 



Thus if a cubic foot of lead is 11.3 times as heavy as a cubic 

 foot of water, the specific gravity of lead is said to be 11.3. 



Every object that is lighter than water will float and will 

 only displace its own weight in water. Thus if a cubic foot of 

 oak is placed in the water, and its specific gravity is .8, its weight 

 will displace 8/10 of a cubic foot of water, and therefore 2/10 

 of the oak will be above water. 



Every object that sinks will displace it own volume of water. 

 Thus a cu. ft. of iron is 7.4 heavier than a cu. ft. of water and 

 will displace one cubic foot of water. 



The following table shows the specific gravity of various 

 substances : 



Specific 



Substance. Gravity. 



Cork .24 



Pine (dry) 55 



Oak (dry) 73 



Ice (melting) 92 



Alcohol 84 



Turpentine 87 



Milk 1.03 



Sugar 1.50 



Coal (bituminous) 1.25 



Coal (anthracite) 1.80 



Sulphuric acid 1 .84 



Gravel ' 2.00 



Marble 2.80 



Flint glass 3.33 



Iron (cast) 7.40 



Brass 8.50 



Copper 8.90 



Silver (cast) 10.49 



Lead (cast) 11.35 



Gold (forged) 19.36 



Platinum 22.00 



PROBLEMS. 



1. A tank is 19 feet long, 4 ft. wide, and 2 ft. deep; what weight 

 of water will it hold? 



2. A cake of ice contains 4 cubic feet; if it is placed in water where 

 it will float, how many cubic inches of ice will be above water? 



3. What is the weight of a cord of dry oak? 



