312 French National Institute, 



ready suggested, that sulphur, and perhaps phosphorus, 

 contains hydrogen. 



We shall not presume to decide between the opinions of 

 Mr. Davy and of Messrs. Gay Lussac and Thenard ; but 

 it will not fail to be remarked, although this cannot lead 

 to any consequence injurious to modern chemistry, that 

 hydrogen, which frequently in the theory of Stahl was 

 nothing else than phlogiston, produces combinations which 

 have all the characters of the metals. 



In addition to the labours we have mentioned, we are 

 indebted to M. Gay Lussac for some observations on the 

 combination of gaseous substatices with each other, which 

 led him to prove that the gases, in such proportions as to 

 render them fit for combination, always produce com- 

 pounds the elements of which are in very simple ratios with 

 each other. Thus, 100 parts of oxygen gas saturate ex- 

 actly 200 parts of hydrogen ; the fluoric and muriatic gases, 

 mixed with the ammoniacal gas, saturate a volume of the 

 latter equal to their own, and form neutral salts, &c. But 

 he observes, that, when we consider the proportions in 

 weight, we obtain no simple ratio between the elements of 

 a similar combination. Moreover, he shows that the apparent 

 contractions which the gases undergo on combining, also 

 form very simple ratios with the primitive volume of the 

 gases, or only with the volume of one of them ; and he af- 

 terwards makes the remark, that the apparent contraction 

 does not indicate the real contraction which the elements 

 have undergone in combining. 



These observations have b^-en followed up by a particular 

 inquiry as to the nitrous vapour and nitrous gas considered 

 as a eudiometrical method. Here we see in a very evident 

 manner the influence of the quantities on the result of the 

 combinations. If we mix 200 parts of nitrous gas with 

 200 parts of oxygen gas, nitric acid is produced; and 100 

 parts of oxygen remain at liberty. If, on the contrary, wc 

 mix 100 parts of oxygen and 400 of nitrous gas, an ab- 

 sorption of 400 parts takes place, which produces nitrous 

 acid, and 100 parts of nitrous gas remain free. Thus we 

 obtain nitric acid, or nitrous acid, according as either of the 

 gases of which these acids are composed is predominant. 



But in both cases the absorptions are always constant. 

 Thus, the nitric acid is composed of 100 parts of azotic 

 gas and 200 of oxygen gas, or 100 of oxygen gas and 200 

 nitrous gas. The nitrous acid results from the combina- 

 tion of 100 parts of oxygen gas and 300 of nitrous gas. 

 And if we add that the nitrous gas is composed of equal 



parts 



