1828.] Sulpho-Naphthalic Acid. 183 



the general nature of this action, I was led to suspect the 

 occasional combination of the hydrocarbonaceous matter with 

 the acid, and even its entrance into the constitution of the 

 salts which the acid afterwards formed with bases. Although 

 this opinion proved incorrect, relative to the peculiar hydro- 

 carbons forming the subject of that paper, yet it led to experi- 

 ments upon analogous bodies, and amongst others, upon naph- 

 thaline, which terminated in the production of the new acid 

 body and salts now to be described. 



Some of the results obtained by the use of the oil-gas pro- 

 ducts are very peculiar. If, when completed, I find them 

 sufficiently interesting, I shall think it my duty to place them 

 before the Royal Society, as explicatory of that action of sul- 

 phuric acid which was briefly noticed in my last paper. 



Most authors who have had occasion to describe naphtha- 

 line, have noticed its habitudes with sulphuric acid. Mr. 

 Brande several years since * stated that naphthaline dissolved 

 in heated sulphuric acid " in considerable abundance, forming 

 a deep violet-coloured solution, which bears diluting with 

 water without decomposition. The alkalies produce in this 

 solution a white flaky precipitate, and if diluted the mixture 

 becomes curiously opalescent, in consequence of the separation 

 of numerous small flakes." The precipitate by alkali was pro- 

 bably one of the salts to be hereafter described. 



Dr. Kidd observes t, that " it blackens sulphuric acid when 

 boiled with it ; the addition of water to the mixture having no 

 other effect than to dilute the colour, neither does any preci- 

 pitation take place upon saturating the acid with ammonia." 



Mr. Chamberlain states J, that sulphuric acid probably de- 

 composes naphthaline, for that it holds but a very small quan- 

 tity in solution. The true interpretation of these facts and 

 statements will be readily deduced from the following experi- 

 mental details. 



1 . Production and properties of the new acid formed from 

 Sulphuric Acid and Naphthaline. Naphthaline, which had 

 been almost entirely freed from naphtha by repeated sublima- 

 tion and pressure, was pulverized ; about one part with three or 



* Quart. Journ. of Science, 1819, viii. 289. f Phil- Trans. 1821, p. 216. 

 J Annals of Philosophy, 1823, N.S. vi. p. 136. 



