USEFUL TABLES 



45 



MEASURES OF TIME 



60 seconds (sec.) =1 minute min. 



60 minutes =1 hour hr. 



24 hours =1 day da. 



7 days =1 week wk. 



4 weeks =1 month mo. 



12 months =1 year yr. 



100 years =1 century C. 



yr. wk. da. hr. min. sec. 



1 = 52 = 365 = 8,765 = 525,948 = 31,556,936 



DECIMAL EQUIVALENTS OF PARTS OF 1 IN. 



WEIGHTS AND SIZES OF MATERIALS 



SPECIFIC GRAVITY 



The specific gravity of a substance is the ratio of the weight 

 of any volume of the substance to the weight of an equal 

 volume of water with solids and liquids, and air with gases. 

 The weight of 1 cu. ft. of any solid or liquid, in pounds avoir- 

 dupois, is found by multiplying its specific gravity by 62.425. 

 The weight, in pounds avoirdupois, of 1 cu. ft. of any gas at 

 atmospheric pressure and at 32 F. is found by multiplying 

 its specific gravity by .08073. 

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