( 49 ) 



II, Swne Observations on Euckloriney relative to the Question ofiti 



Composition. 



When my brother, the late Sir Humphry Davy, in 1815, dis^ 

 covered that combination of chlorine and oxygen which has 

 since been called Deutoxide of Chlorine, he was in doubt whe-- 

 ther to consider euchlorine a true chemical compound, or a mix- 

 ture of the new gas and chlorine. He remarked, " that two in 

 volume of this gas, and three in volume of chlorine, would pro- 

 duce by explosion the same products as euchlorine." The only 

 facts he was aware of opposed to this idea was, that Dutch foil, 

 which burns in a mixture of two volumes of common air, and 

 one of chlorine, remains unaltered in euchlorine, which could 

 hardly be expected unless the latter were a definite compound* 

 But, he adds, " The force of this argument is suspended, till it 

 be supported by an experiment, shewing that Dutch foil inflames 

 in a mixture of two of the deep yellow gas, and three of chlo- 

 rine." This experiment he had not an opportunity of making 

 at Rome, where he discovered the new gas, no foil of the kind 

 being procurable there ; but, on his arrival in England, a few 

 months after, he did not delay trying it. The result was nega- 

 tive ; the mixture, in the proportions above stated, had no effect 

 on Dutch foil ; and hence he concluded, " that the deep-co- 

 loured gas and chlorine have a chemical action on each other, 

 and that euchlorine is not a simple mixture of them." How- 

 ever, he drew this conclusion merely on the ground of probabi- 

 lity ; he intQi^ded to prosecute the subject, and hoped soon to 

 present some new results*. But this he did not accomplish, 

 his attention, almost immediately, having been directed to more 

 important objects of research, especially fire-damp and the safety- 

 lamp. 



Since that time, the nature of euchlorine has remained an un- 

 settled question. The majority of chemists, and some of the 

 highest authority, as Berzelius and Gay Lussac, have considered 

 it a definite compound ; — whilst a few have more inclined to the 

 idea, that it is merely a mixture, founding their opinions chiefly 



• Philosophical Transactions, 1816, p. 219. 

 VOL. XVII. NO. XXXIII. JULY 1834. D 



