72 Royal Society : — 



to 4 volumes of vapour, requires 2*9. According to the monatomic 

 view, a vapour-density of 1*45 should have been found. 



The preceding experiments, although fixing in a satisfactory 

 manner the composition and the equivalents of the two diammonias, 

 do not unveil their molecular constitution — their degree of substi- 

 tution. 



I have endeavoured to solve this problem by submitting them to 

 the action of iodide of ethyle, a process which I first used for simi- 

 lar purposes, and which has since become of general application. 

 This process, moreover, could not fail to furnish a final decision 

 between the two theories. 



In considering with M. Cloez the two bases as primary monamines 

 belonging respectively to the formic and to the acetic groups, 



C 2 H] C 4 H 3 ] 



H N . H N, 



H J H J 



it is evident that each of them must be capable of absorbing success- 

 ively 1, 2, or 3 equivalents of ethyle, and of yielding three ethylated 

 bases, two volatile, and one fixed. On the contrary, if the bases were 

 products of the successive substitution of the same molecule for the 

 hydrogen of two equivalents of ammonia, if they were respectively a 

 primary and a secondary diamine, 



(C 4 HJ"1 (C.H,)' 



i.HJ"l (C 4 H t )"l 



H, lN 2> (C 4 H 4 )"In 2 , 



H 2 H a J 



the first of the two must likewise give rise to the formation of three 

 bases, whilst the second one would produce only two. 



Experiment has verified this latter anticipation. In submitting 

 ethylene-diamine to the alternate action of iodide of ethyle and oxide 

 of silver, I have succeeded in obtaining two volatile ethylated bases, 

 and a third one, which is fixed. These compounds are well defined ; 

 their composition was established by the analysis of their iodides or 

 their platinum-salts. Represented as salts, these bases contain — 



Saltofethylene-diammonium [(C 4 H 4 )" H 6 N 2 ]"I a . 



Salt of diethylated ethylene-diammonium . . [(C 4 HJ" (C 4 H 6 ) 2 H 4 N J" I a . 



Salt of tetrethylated ethylene-diammonium [(C 4 HJ" (C 4 H 5 ) 4 H 2 NJ" I,. 



Salt of hexethylated ethylene-diammonium [(C 4 H 4 )" (C 4 H 5 ) 6 N J" I 2 



On repeating the same experiments with diethylene-diamine, per- 

 fectly analogous phenomena were observed, but the reaction yielded 

 only one volatile base, which was immediately converted into a fixed 

 base. Analysed in a similar manner, and represented as salts, these 

 bases exhibit the following composition :— 



Salt of diethylene-diammonium [(C 4 H 4 )" 2 H 4 Nj" I 2 . 



Salt of diethylated diethylene-diammonium [(C 4 H 4 )" 2 (C 4 H 5 ) 2 H 2 N J" I 2 . 



Salt of tetrethylated diethylene-diammonium [(C 4 H J" 2 (C 4 H 5 ) 4 N J" I a . 



