XIV OBITUARY NOTICES. 



memoir " contained the first distinct recognition of the existence 

 of perfectly well-defined and crystallized salts of ammonia-cobalt 

 bases." Indeed, it would appear that no trace exists "in any 

 earlier paper of even an idea of the existence of such a class of 

 compounds." The results given in this paper were first obtained 

 in 1847 m Marburg, while the author was chemical assistant to 

 Prof. Bunsen and during the latter's absence in Iceland. They 

 were freely communicated verbally to others and a suite of the salts 

 obtained were deposited at the time in the laboratory at Giessen. 

 In this early memoir Dr. Genth describes two series of salts in 

 which cobalt oxide, conjugated with ammonia, acts as a base. To 

 prepare these bases, ammonium chloride is added to a solution 

 either of cobaltous chloride or sulphate, and the solution is satur- 

 ated with ammonia. After standing four or five weeks in the air 

 and the excess of ammonia has evaporated, hydrochloric acid is 

 added to acid reaction and the solution is boiled. After some time 

 a crystalline heavy carmine red powder is deposited, consisting of 

 small octahedrons having the empirical formula, Co 2 3 (NH.j) 3 Cl. 

 Hence they must be considered as the chloride of a paired or con- 

 jugated compound, Co 2 3 (NH 4 ) 8 , which plays the part of a metal. 

 On further evaporating the mother-liquor from which the carmine 

 red salt was obtained, an orange-yellow cobalt salt separated in 

 crystals. " Though the analyses were from necessity not sufficiently 

 complete and extended to fix the constitution of the bases in ques- 

 tion, yet the fact is indisputable that this memoir contained not 

 merely the first announcement of the existence of ammonia-cobalt 

 bases, but also a scarcely less accurate and complete description of 

 two of these bases than any which has since appeared." 



The foregoing memoir was called by Dr. Genth a preliminary 

 notice. But inasmuch as circumstances prevented a prompt resump- 

 tion and continuation of the investigation, the field was entered by 

 others. In 185 1 Claudet described purpureocobalt ; and later in 

 the same year Fremy communicated to the French Academy " the 

 discovery of a class of compounds containing cobalt and ammonia, 

 and produced by the oxidation of ammoniacal solutions of cobalt- 

 ous salts," claiming the discovery as his own. He "appears not 

 to have been aware that these two bases had been described in a 

 manner little less complete than his own two years before the 

 appearance of his memoir." 



This publication by Dr. Genth interested chemists greatly, and 



