1863.] 641 



acid. The basic compound which distils over has the same compo- 

 sition as phenylene-diamine, viz. C 6 H 8 N 2 , and presents in its pro- 

 perties many analogies with this substance, but it is far from being 

 identical with it. The two diatomic bases obviously are related to 

 each other in the same manner as the two nitranilines from which 

 they are derived, and I propose therefore to distinguish them as 

 alpha-phenylene-diamine and beta-phenylene-diamine. Beta-phe- 

 nylene-diamine differs from alpha-phenylene-diamine by its superior 

 crystallizing power : whilst the latter for days and often for weeks 

 remains liquid, the former immediately, when separated from one of 

 its salts by an alkali, solidifies into a beautifully crystalline mass. The 

 fusing-point of alpha-phenylene-diamine is 63 (corr.), that of beta- 

 phenylene-diamine is 140 (corr.) ; the former boils at 287 (corr.), 

 the latter at 267 (corr.). Beta-phenylene-diamine is remarkable 

 for the facility with which it sublimes even at temperatures below 

 its boiling-point. The experiment succeeds particularly well in a 

 current of hydrogen gas, when the base is obtained in splendid cry- 

 stalline plates resembling pyrogallic acid. 



The salts of beta-phenylene-diamine, although they are more 

 soluble than the corresponding alpha-phenylene-diamine salts, are 

 distinguished by the same superior crystallizing power. They are all 

 remarkable for the facility with which they yield beautiful and mostly 

 well-formed crystals. 



I have examined only two of these salts somewhat more mi- 

 nutely. 



Hydrochlorate of Beta-phenylene-diamine. This salt crystallizes 

 in large prisms, which are at present in the hands of M. Quintino 

 Sella. Extremely soluble in water, difficultly soluble in hydrochloric 



acid, it contains 



C 6 H 8 N 2 , 2HC1. 



Hydrobromate of beta-phenylene-diamine resembles in every respect 

 the hydrochlorate. The crystals, which were found to have the 



formula 



C 6 H 8 N 2 , 2HBr, 



are apt to assume a reddish tint when left in contact with the air. 



Platinum-salt. Light-yellow plates extremely soluble in water 

 and readily decomposed by heat. Composition : 

 C 6 H 8 N 2 , 2HC1, 2PtCl. 



