on the Atomic Weights of Kodies. 



183 



as 42 volumes, while that of the air continued 100, the 

 result of the combustion was somewhat different. The 

 diminution of bulk, in three successive experiments made 

 exactly in the same way, was always 60 volumes. Now, 

 the third part of 60 or 20 is the amount of the oxygen in 

 100 volumes of air, according to these trials. The azotic 

 gas, of course, must be 80 volumes. Thus, the result of 

 these experiments coincides with the opinion, that air is a 

 chemical compound of four volumes azotic and one volume 

 oxygen gas, or that it is a compound of two atoms azote 

 and one atom oxygen.* 



To verify these results, I placed a cubic inch or 100 

 measures of air in a glass vessel inverted over mercury, 

 and then let up into the vessel a stick of phosphorus, of 

 such a length as to reach to the top of the little vessel con- 

 taining the air. The phosphorus and air were left together 

 for two days, and till all action was at an end. The air was 

 then transferred to the water trough, well washed to get 

 rid of the phosphoric acid formed, and the residue measured 

 in the usual manner. This analysis of air by phosphorus 

 was repeated ten times. The following table shews the 

 result. 



Mean 100 ... 79-9335 

 The reader will observe, that in every one of these ten 

 trials, the residue or the azotic gas in 100 volumes of air 



• If the hydrogen gas be more than VI tie- diminution of bulk, after the explo- 

 sion, increases very slowly ; but 100 air and 48 or 50 hydrogen gave very nearly 

 a diminution of 63, though never quite so much. This was the diminution found 

 by Humboldt and day LllMBO. 



