Dr. Hofinann on the Diatomic Ammonias. 71 



to remove all hypothesis from the above explanation, — the determina- 

 tion of the vapour-density of the anhydrous base. 



The experiment made with a substance the purity of which had 

 previously been proved by analysis, led to the number 2*00, which 

 indeed absolutely coincides with the theoretical density of the 

 diatomic formula C 4 H 8 N 2 referred to 4 volumes. This theoretical 

 density is 2*07, whilst the formula of M. Cloez, likewise referred to 

 4 volumes, requires the theoretical density of 1*00. 



The molecule of ethylene-diamine (formenamine) then, like those 

 of all other well-examined organic compounds, corresponds to 4« 

 volumes of vapour ; and the vapour-density of the base, far from 

 militating against the molecular value which I assign to this body, 

 furnishes on the contrary an additional and incontestable argument 

 in its favour. 



The preceding remarks are, I hope, sufficient to establish the 

 formulae of the diatomic ammonias upon a solid basis. I will there- 

 fore only briefly allude to some results which I have obtained in 

 studying the products of decomposition of ethylene- diamine, and 

 which are not less characteristic. Submitted to the action of nitrous 

 acid, this base is decomposed with evolution of nitrogen ; in the first 

 stage of the reaction an indifferent crystalline body is produced, and 

 the final result of the process is a large quantity of pure oxalic acid. 

 The nitrogen evolved during the transformation is accompanied by a 

 very volatile liquid, the odour of which is somewhat similar to that 

 of aldehyde. At the time when I made these experiments I really 

 believed the liquid to be aldehyde, but since I failed in obtaining the 

 crvstalline compound with ammonia and in transforming it into acetic 

 acid, I abstained from mentioning this reaction in my note to the 

 Royal Society. I have now scarcely a doubt that the volatile liquid 

 was the oxide of ethylene, isomeric with aldehyde, since discovered 

 by M. Wurtz. The transformation would be 



C 4 H 8 N 2 + 2N0 3 =4N + C 4 H 4 2 +4HO. 



In preparing the ethylene-diamine for my experiments, I obtained 

 as a secondary product a small quantity of the second base, which 

 M. Cloez has described as acetenamine, and for which I now propose 

 the term diethylene-diamine. This base has exactly the same per- 

 centage composition, whether viewed as a diamine or considered as 

 the monatomic acetenamine of M. Cloez. The analysis of the base 

 itself, and of some of its salts, fully confirms the results obtained by 

 that chemist. But this base is no primary monamine.; it does not 

 contain the radical acetyle, C 4 H 3 , as supposed by M. Cloez ; it is a 

 secondary diamine containing two molecules of ethylene. Aceten- 

 amine, as conceived by M. Cloez, should be formed by the action of 

 chloride, bromide, and iodide of vinyle (C 4 H 3 C1, C 4 H 3 Br, C 4 H 3 I) 

 upon ammonia. These reactions do not furnish a trace of the base 

 in question. But there is a more conclusive proof of the diatomic 

 nature of this body, the evidence of which will not be contested by 

 M. Cloez, — this is the determination of the vapour-density. Experi- 

 ment gave the number 27. The diatomic formula, C 8 ~~ 



