EXAMPLES. 131 



Ice (at 0), . . . 0.926 

 Sea-water, . . . 1.027 

 .Olive-oil, . . . 0.915 



Alcohol,. . . . 0.794 

 Ether, 0.724 



Ratios of the densities of gases and vapors of differ- 

 ent substances to that of atmospheric air at the same 

 temperature and under the same pressure. 



Oxygen, . . . . 1.103 



Hydrogen, . . . 0.069 



Nitrogen, . . . 0.976 



Chlorine, . . - 2.44 



Bromine, . . . 5.395 



Iodine, . . . . 8.701 



Arsenic, .... 10.365 



Mercury, . . . 6.978 



Water, .... 0.62 



Alcohol, . . . . 1.613 



Carbonic Acid, . 1.524 



Ammonia, . . . 0.591 



Sulphurous Acid, 2.212 



Sulphuric Acid, . 2.763 



Ether, . . . . 2.586 



EXAMPLES. 



1. If the barometer stand at 28.372 inches, find the 

 pressure on a square inch. Ans. 13.902 Ibs. 



2. If the elastic force of a vapor sustain a column of 

 mercury 3.34 inches high, find its pressure on a square 

 inch. Ans. 1.64 Ibs. 



3. A cubic inch of mercury at 16 weighs 3429^ grs. 

 nearly, and the barometer stands at 30 inches. Find (1) 

 the atmospheric pressure on the square inch of surface, and 

 (2) the height of a barometer filled with water instead of 

 mercury, the specific gravity of mercury being 13.6. 



Ans. (1) 14.698 Ibs. ; (2) 34 feet. 



4. A~ hollow cylinder, open at the top, is inverted, and 

 partly immersed in water. It is required to find the depth 

 of the surface of the water within the cylinder below the 

 surface of the water without. 



Let a = the length of the cylinder, b = the length of 

 the part not immersed, x = the required depth of the sur- 



