XXI 



The corrections to which the experiments previously mentioned had 

 led, as regards the composition of carbonic acid and water, suggested 

 also a re-examination of atmospheric air. Dumas undertook this 

 investigation in conjunction with his friend Boussingault. The 

 method of analysis adopted was exclusively ponderal. 



The composition of air thus arrived at by Dumas and Boussingault 

 is 



By weight. By volume. 



Oxygen 23 2O81 



Nitrogen 77 79'19 



100 .... 100-00 



The rectification of the atomic weight of carbon and the inquiries 

 more immediately connected therewith must be looked upon as the 

 prelude of Dumas's long series of researches on the atomic weights of 

 the elements. They were mostly published at a later period (from 

 1858 to 1860). A few fragmentary statements must suffice to convey 

 to the reader an idea of the magnitude and variety of these researches. 

 They embrace not less than thirty elements, or about one-half of those 

 then known ; the number of experiments made for the purpose of 

 fixing their atomic weight closely approach 200, so that on an average 

 about six separate analyses were made in each case. 



Among the researches carried out by Dumas in conjunction with 

 other chemists we have still to notice those with Malaguti and 

 Leblanc on the transformation of the ammonic salts and amides into 

 the alcohol cyanides (nitriles), those with Cahours on the composition 

 of the neutral nitrogenous substances in the vegetal and animal 

 organism, those with Milne Edwards on the conversion of sugar into 

 fat (wax) within the organism of the bee. 



The last experimental inquiries published by Dumas are his re- 

 searches on alcoholic fermentation (1872), and an interesting paper 

 on the occlusion of oxygen in silver, which appeared as late as 1878. 



Lucidity of exposition and grace of style are not necessarily asso- 

 ciated with the gift of successfully interrogating nature. It happens 

 but too frequently that the results of admirable inquiries are almost 

 hidden in papers hastily, not to say negligently, written. But no one 

 ever found fault with Dumas in this respect. Few chemists, perhaps, 

 published their researches in a more attractive and lucid form. And 

 the same graceful elegance and perspicuity of style are found in 

 whatever proceeded from his pen. One might fancy that he took the 

 same pains whether it was a friendly letter or an elaborate report, a 

 festal oration or a philosophic essay that he was writing ; or, perhaps, 

 we should rather say, they seem all to have been written with the 

 same facility. 



The works of Dumas present considerable variety, both as to the 



