471 



WEIGHT AND SPECIFIC GRAVITY OF DIFFERENT 

 GASES. 



Fahrenheit's Thermom. 55 Barometer 30 inches. 



Spec. Gray. Wt. Cub. Foot. 



Atmospheric air . 1.2 . 525.0 grs. 



Hydrogen gas . 0.1 43.75 



Oxygen gas . ; 1.435 . 627.812 



Azotic gas . . 1.182 . 517.125 



Nitrous gas . v< fj 1.4544 . 636.333 



Ammoniac gas. ""*.-.. .7311 . 319.832 



Sulphureous acid gas . 2.7611 . 1207.978 



In this table the weights and specific gravities of the principal gases are given, 

 as they correspond to a state of the barometer and thermometer which may be 

 chosen for a medium. The specific gravity of any one gas to that of another will 

 not exactly conform to the same ratio under different degrees of heat and other 

 pressures of the atmosphere. 



And if common air, the standard, be taken at unity (1); chlorine oxy muriatic 

 acid will be 2.500 ; and hydrogen 0.069 ; whence we conclude that chlorine is 2 

 times heavier than hydrogen, and this last is 14 times lighter than common air. 

 For, to arrive at the absolute weight of the gases, we have only to assume 100 cubic 

 inches of atmospheric air to weigh 30.5 grains, and as there are 1728 cubical inches 

 in a cubic foot, the simple proportion 



100 : 30.5 grains : : 1728 : 527.04 grains, 

 the weight of a cubic foot of common air. 



And for any other gas, it is only necessary to observe its specific gravity in 

 relation to that of common ah-; for example, chlorine has a specific gravity of 2.5; 

 hence a cubic foot of chlorine will weigh 2 times as much as a cubic foot of 

 common air ; for 



527 .04 x2 =1317.6 grains, 

 the weight of a cubic foot of chlorine. 



To determine the weight of any gas lighter than common air, we also compare 

 their specific gravities : thus, the specific gravity of ammoniacal gas is 0.5, and 

 that of atmospheric air being =1, we have 1 : 0.5 : : 1728 : 864.0, or simply 

 1728-J-2=864 grains, for the weight of a cubic foot of ammoniacal gas; and so on 

 for all the other gaseous bodies, as they are arranged in the following table. 



