532 



are thus produced. For the present I will mention only some of the 

 properties of phenylene-diamine and toluylene-diamine, in order to 

 give an idea of the general character of this class of bases. 



Phenylene-diamine. 



Freshly distilled, it presents itself as a slightly coloured heavy oil, 

 which, like phenylamine, has a tendency to assume a brown coloration 

 on exposure to the atmosphere. The base remains liquid often for 

 days, and then gradually solidifies into a mass of crystals, which be- 

 come hard and white hy washing with ether. The '.fusing-point of 

 phenylene-diamine is 63. Its boiling-point is near 280 ; it distils 

 without alteration. This substance is very soluble in water and 

 alcohol ; the solutions have a distinctly alkaline reaction. It is far less 

 soluble in ether. Phenylene-diamine contains 



C 6 H 8 N 2 = H 2 N 2 . 



H 



This base, as might have been expected, is diacid. A beautifully 

 crystallized sulphate was found to contain 



The dichloride is very soluble in water, but was easily crystallized 

 from concentrated hydrochloric acid. It was found to contain 



Addition of dichloride of platinum to the solution of the chloride 

 furnishes the platinum-salt, which crystallizes in splendid needles of 

 the composition 



Phenylene-diamine is remarkable for the facility with which its 

 salts, as well as its other derivatives, crystallize. In this respect it 

 worthily emulates its monatomic correlative, phenylamine. The 

 bromide and iodide are separated at once, in the form of crystalline 

 masses, when phenylene-diamine is brought in contact with the 

 respective acids. The salts thus produced crystallize splendidly from 

 water, and more especially from alcohol. The nitrate and oxalate are 

 not less beautiful. The salts of phenylene-diamine are readily 

 decomposed by the fixed caustic alkalies ; the base is thus separated 



