SPECIFIC GRAVITY OF HYDROGEN GAS. 71 



we have seen in the last section, that 100 cubic 

 inches of oxygen gas weigh 33*91.5 grains ; 

 now 



2-119 : 33-915: : 1 : 16-005. 



This approaches so nearly the ratio of 1 : 16, that 

 it leaves no doubt that the specific gravity of oxy- 

 gen gas is exactly 16 times greater than that of 

 hydrogen gas. Consequently, the specific gravity 

 of hydrogen gas is Ye 1 -, or 0*0694; or exactly 

 the specific gravity already deduced by Dr. 

 JProut, from other considerations, and which I 

 obtained experimentally, as may be seen in my 

 Essay on the Specific Gravity of Gases. 



That the proportion between the specific 

 gravities of oxygen and hydrogen gases, is that 

 of 16 : 1, is farther confirmed by an experiment 

 of Berzelius and Dulong. They made dry hy- 

 drogen gas pass through a determinate weight of 

 oxide of copper, heated to redness. The water 

 thus formed was collected by means of dry 

 chloride of calcium. The loss of weight sus- 

 tained by the oxide of copper gave the weight 

 of the oxygen in the water, while the weight of 

 the hydrogen was denoted by the difference be- 

 tween the weight of the water and the oxygen : 

 the mean of three trials gave the oxygen 889, 

 and the hydrogen 111. Now 111 : 889 : : 1 : 

 8*009 ; and as water is a compound of 2 volumes 

 hydrogen to 1 of oxygen, it follows, that the 



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