T. S. Hunt — Chemical Integration. 121 



§ 9. In a later note, on the Relation between certain Bodies 

 differing by H 2 .and 0„ presented to the same Academy in 

 1855, after recalling the above conclusions as to homologous 

 series, it was maintained that similar relations may exist be- 

 tween bodies differing in their proportions of oxygen or of 

 hydrogen. In support of this thesis, as regards oxygen, were 

 then compared alike chemically and crystal lographically, malic 

 and tartaric acids, chlorates and perchlorates, sulphates, car- 

 bonates and sulphato carbonates. As regards hydrogen, the 

 compound ammonias, NH,+n(CH 2 ), were compared with the 

 analogous base piperidine, belonging to a series NH + n(CET 2 ), 

 and with arsine or methyl arsenid, AsH-f CH„. These facts, 

 and other considerations, it was then argued, " lead us to admit 

 an intimate relation between bodies differing bv H 2 " as well as 

 by 0, (0 = 8).* 



§ 10. A further illustration of this extension of the concep- 

 tion of progressive series was soon afterwards afforded by the 

 studies of J. P. Cooke on the crystallized alloys of zinc and an- 

 timony, which, with similar crystalline forms, present consider- 

 able variations in the proportions of their constituents, leading 

 him to the conclusion that "zinc and antimony are capable of 

 uniting in other proportions than those of their chemical 

 equivalents, or, in other words, that the law of definite propor- 

 tions is not so absolute as has been hitherto supposed. "f In 

 commenting on these results, as they had been set forth by 

 Cooke in 1860, it was said by the writer in 1874 : " These al- 

 loys of varying composition are to be regarded in part as 

 examples of a progressive series of isomorphous compounds of 

 antimony and zinc, of high equivalent, differing from each 

 other nZn — and in part doubtless as crystalline mixtures of 

 these isomorphous homologous species. The principle em- 

 bodied in the conception advanced by Prof. Cooke, and rightly, 

 regarded by him as of great importance to a correct science of 

 mineralogy, he has named allomerism. It is evidently a case 

 of homologous and isomorphous relations between members of 

 a progressive series, — a general principle upon which I have 

 insisted throughout the pages of this paper [one in the Compte 

 Eendu of the French Academy of Sciences r for June 29, 1863, 

 there reprinted,] and which includes the polymeric isomorph- 

 ism of Scheerer."^: 



§ 11. If now, as was argued in 1853-1855, the equivalent or 

 integral weights of liquid and solid species are represented by 



* Coraptes Rendus de l'Academie des Sciences, xli, 1167; sur les rapports 

 entre quelques composes different par H 2 et 2 . "Nous portent a admettre ua 

 rapport intime entre les corps differants par H 2 ." 



\ Cooke, this Journal, 1883, xxvi, 310-316, resuming the conclusions of his 

 studies of 1855 and 1860. 



\ Hunt, Chemical and Geological Essays, 447. 



