I 



XV 



methide, ordinary aldehyde being acetyl hydride ; this received 

 powerful support from Williamson's study of the genesis of acetone 

 and its homologues by heating barium salts of the fatty acids ; while 

 Freund's synthesis of acetone by means of zinc ethide and acetyl 

 chloride, together with the work of Boutlerow, Fried el, and Crafts, 

 involved a further modification, so that acetone and its homologues 

 are now simply regarded as compounds of carbonyl with two alcohol 

 radicals. Thus the difficult problem undertaken by Kane more than 

 half a century ago, when very vague notions prevailed as to the 

 constitution of some of our most common carbon compounds, required 

 the more powerful methods of modern chemistry for its complete 

 solution. 



The derivatives of ammonia early attracted Professor Kane's atten- 

 tion, as his friend Dumas had shown in 1830 that oxamide, C 2 2 (]N"H 2 ) 2 , 

 included the ammonia residue NH 2 , which he termed amide; and 

 that many substances existed which might be supposed to contain 

 the same group. Kane, starting with this general idea, commenced 

 the examination of a number of inorganic compounds which might 

 contain the group NH 2 . The most interesting of these is the " white 

 precipitate of mercury," which had long been known, and about 

 whose composition conflicting statements were made. Kane studied 

 the formation of that body with great care, and showed that a definite 

 compound free from oxygen could be obtained under proper conditions, 

 whose composition is represented by the formula HgISrH 2 Cl. He 

 was led by his work on this substance, and on similar compounds of 

 other metals, to conclude that the three atoms of hydrogen in ammo- 

 nia, NH 3 , are not removed with equal readiness in chemical exchange, 

 and that ammonia is, in fact, the hydride of a persistent group, NH 2 , 

 which he termed amidogene. 



Kane's amidogene theory, and its consequences as affecting the view 

 taken of the constitution of ammoniacal salts, attracted great inte- 

 rest at the time. That Berzelius attached much importance to Kane's 

 work is evident from the remark attributed to him in Wohler's 

 - Jahresbericht ' for 1838, " Diese Untersuchungen von Kane gehoren 

 meiner Ansicht nach zu den wichtigeren des verflossenen Jahres." 

 Although subsequent investigations of Wurtz, Hofmann, and many 

 others have shown that the three atoms of hydrogen in ammonia can 

 be successively replaced by methyl or ethyl without affording the 

 metameric mono- or di- substituted derivatives which might be expected 

 to exist on the amidogene theory, it is interesting to note that 

 Curtius, working nearly fifty years after Kane's papers were pub- 

 lished, has succeeded in obtaining the hydrate of diamidogene, 

 NH 3 — ^Sgj or as *k ^ s now termed hydrazine. 



Kane was awarded the Cunningham Medal of the Royal Irish 

 Academy in 1843 for his researches on the above subject. 



