IN PHYSICS, 213 



and since 



mass 

 volume 



specific gravity ' 

 we have 



A _ * , y_. 



B ~ x + / ' 

 whence we find (approximately), 



Gold = 13.95 

 Silver = 8.05 



40. Why will oily which floats on water, sink in alco- 

 hol ? 



The specific gravity of absolute alcohol is only .79 ; 

 hence even the dilute alcohol of commerce is lighter 

 than water. 



41. A specific-gravity bottle holds 100 gms. of water and 

 1 80 gms. of sulphuric acid. Required the density of the 

 acid. 



Ans. 1.8. 



42. What is the density of a body which weighs 58 gms. 

 in air and 46 gms. in water ? 



Ans. 4f. 



43. What is the density of a body which weighs 63 gms. 

 in air and 35 gms. in a liquid of a density of 3>$ ? 



Ans. 1.9125. 



HYDRAULICS OR HYDRODYNAMICS. 

 103. 1-5. (See Key, pp. 29, 30.) 



