OXYGEN AND HYDROGEN GASES. 



specific gravity of hydrogen is to that of oxygen 

 gas as 1 : 16-018.* 



In my experiment, the oxygen was more than 

 16 times heavier than the hydrogen gas by smooth 

 part in that of JBerzelius and Dulong it was a 

 little more. The mean of both (which must come 

 very near the truth) gives us the specific gravity 

 of hydrogen to that of oxygen gas, as 1 : 16*011. 

 That the true specific gravity of oxygen gas 

 is I'll 11, will be shown in the fifth chapter of 

 this work.t 



The following table exhibits the most recent 

 specific gravities of hydrogen gas obtained by 

 experiment : 



SP. GR. OF HYDROGEN GAS. 



0-0732 . . Biot and Arago. 



0-0694 . . Thomson. 



0-0688 . . Berzelius and Dulong. 



It is obvious, when we compare these with the 

 above found specific gravity of hydrogen gas, 

 which must be exceedingly near the truth, that 



* Ann. de Chim. et de Phys. xv. 389. 



f I ought to mention that the weight of my flask filled with the dilute 

 sulphuric acid and zinc, was about 3000 grains, and that of the tube filled 

 with muriate of lime, about 1000 grains. My scales, loaded with double 

 that weight, turned sensibly with ^o^th of a grain. Hence, I consider 

 myself as certain of the weight of the hydrogen gas to as many decimal 

 places as I have given in the text. I weighed so as to make myself sure 

 of the accuracy within yy^th of a grain : Berzelius and Dulong deter- 

 mined the composition of water by an experiment nearly similar. Their 

 result does not tally exactly with mine, nor can I institute a comparison, 

 because they do not state the delicacy of their balance. 



