128 ON THE THEORY OF TYPES IN CHEMISTRY. 
The above, which we conceive to be a simple statement of the 
process as it takes place in nature, dispenses alike with hypothetical 
radicals 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 carbonic anhydrid 
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,0O,, like the other anhydrids, as only a derivative of the 
type of water, and eventually of the hydrogen type. 
These views were first put forward by myself in 1848, when I ex- 
pressed 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 ac- 
knowledgment, adopted my own.—(Ann. de Chim. et Phys. (3) 
xxxvii. 285.) Already in 1851, Williamson, in a paper read before 
the British Association, had developed the ideas on the water type to 
which Wurtz refers above, and to him the English editor of Gme- 
lin’s Handbook ascribes the theory. The notion of condensed types, 
and of H, as the primal type, was not, so far as I am aware, brought 
forward by either of these, and remained unnoticed until resuscitated 
by Wurtz in 1855, seven years after I had first announced it, and one 
year of my reclamation, 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 remarks that in a 
previous paper, he had attributed the theory of water types to Ger- 
hardt and Williamson, and 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 theory to the so-called oxygen acids and to 
the anhydrids, and in whose earlier papers may be found the germs 
of most of the ideas on classification usually attributed to Gerhardt 
and his disciples.” — (Proc. Am. Assoc. Baltimore, May, 1858, p. 197.) 
It will be seen, from what precedes, that I not only applied the 
theory, as Dr. Gibbs remarks, but except so far as Laurent’s sug- 
gestion goes, invented it and published it in all its details some years 
before it was accepted by a single chemist. 
