18 Mr. T. S. Hunt on the Theory 



bibasic acids. In extending and developing this idea of Lau- 

 rent's, I insisted in March 1848, and again in January 1850, 

 upon the relation between the alcohols and water as one of ho- 

 mology, water being the first term in the series, and H 2 being 

 in like manner the homologue of acetene and formene, while 

 the bases of Wurtz were said to " sustain to their corresponding 

 alcohols the same relation that ammonia does to water*." 



In a notice of his essay, published in September 1848f, I 

 endeavoured to show that Laurent's view might be further ex- 

 tended, so as to include in the type of water " all those saline 

 combinations (acids) which contain oxygen f and in a paper read 

 before the American Association for the Advancement of Science 

 at Philadelphia, in September 1848, I further suggested that as 

 many neutral oxygenized compounds which do not possess a 

 saline character are derivatives of acids which are referable to 

 the type H 2 O 2 , " we may regard all oxygenized bodies as belong- 

 ing to this type," which I further showed in the same essay is 

 but a derivative of the primal type H 2 , to which I referred all 

 hydrocarbons and their chlorinized derivatives, as also the vola- 

 tile alkaloids, which were regarded " as amidized species u of 

 the hydrocarbons, in which the residue amidogen, N H 2 , re- 

 placed an atom of H or CI, or what is equivalent, the residue 

 N H was substituted for O 2 in the corresponding alcohols J. 



In the paper published in September 1848, I showed that 

 while water is bibasic, the acids which, like hypochlorous and 

 nitric acids, were derived from it by a simple substitution of CI 

 and NO 4 for H, were necessarily monobasic ; and I then pointed 

 out the possible existence of the nitric anhydride (N0 4 ) 2 2 , 

 which was soon after discovered by Deville. Gerhardt at this 

 time denied the existence of anhydrides of the monobasic acids, 

 while he regarded anhydrides as characteristic of polybasic acids, 

 and indeed was only led to adopt my views by the discovery of 

 the very anhydrides whose formation I had foreseen §. 



In explaining the origin of bibasic acids, I described them as 

 produced by the replacement, in a second equivalent of water, of 

 an atom of hydrogen by a monobasic saline group ; thus sul- 

 phuric acid would be (S 2 H0 6 H)0 2 . Tribasic acids, in like 

 manner, are to be regarded as derived from a third equivalent of 



* American Journal of Science [2], vol. v. p. 265 ; vol. ix. p. 65 ; vol. xiii. 

 p. 206. 



f Ibid. vol. vi. p. 173. % Ibid. vol. viii. p. 92. 



§ The anhydrides of the monabasic acids correspond to two equivalents 

 of the acid, minus one of water, as 2(C 4 H 4 4 )-H2 2 =C 8 H 6 6 , while 

 one equivalent of a bibasic acid (itself derived from 2(H 2 2 )) loses one of 

 water, and becomes an anhydride, as C 2 H 2 6 —H 2 2 ==C 2 4 . So that 

 both classes of anhydrides are to be referred to the tvpe of one molecule 

 of water, H 2 O 2 . 



