468 THEORY OF TYPES IN CHEMISTRY. [XX. 



The mode of the generation of acids set forth in the case of 

 those derived from phosphoric anhydride, which we conceive 

 to be a simple statement of the process as it takes place in 

 nature, dispenses alike with hypothetical radicles and residues, 

 both of which are, however, convenient for the purposes of 

 notation. In the selection of a typical form to which a great 

 number of species may be referred, hydrogen or water merits 

 the preference from its simplicity, and from the important part 

 which it plays in the generation of species. Water and car- 

 bonic anhydride are both so directly concerned in the generation 

 of the bodies in the carbon series, that either may be assumed 

 as the type ; but we prefer to regard C 2 4 , like the other an- 

 hydrides, as only a derivative of the type of water, and ulti- 

 mately of the hydrogen-type. 



These views were first put forward by myself in 1848, when 

 I expressed the opinion that they were destined to form " the 

 basis of a true natural system of chemical classification " ; and 

 it was only after having opposed them for four years to those 

 of Gerhardt, that this chemist, in June, 1852, renounced his 

 views, and, without any acknowledgment, adopted my own. 

 (Ann. de Chim. et Phys. (3), XXXVII. 285.) Already in 

 1851, "Williamson, in a paper read before the British Associa- 

 tion, had developed the ideas on the water-type to which Wurtz 

 refers above, and to him the English editor of Gmelin's Hand- 

 book ascribes the theory. The notion of condensed types, and 

 of H 2 as the primal type, was not, so far as I am aware, brought 

 forward by either of these, and remained unnoticed until re- 

 suscitated by Wurtz in 1855, seven years after I had first an- 

 nounced it, and one year after my reclamation already noticed, 

 which was published in the American Journal of Science, in 

 March, 1854. 



My claims have not, however, been overlooked by Dr. 

 Wolcott Gibbs. In an essay on the polyacid bases, he re- 

 marks that in a previous paper he had attributed the theory 

 of water-types to Gerhardt and Williamson, ami adds: "In 

 this I find I have not done justice to Mr. T. Sterry Hunt, to 

 whom is exclusively due the credit of having -first applied the 



