Afr. Faraday on the mutual action of sulphuric acidy ^c. 141 



Mr. Brands, several years since,* stated that naphthaline 

 dissolved in heated sulphuric acid " in considerable abund- 

 ance, 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 conse- 

 quence of the separation of numerous small flakes." The 

 precipitate by alkali was probably one of the salts to be 

 hereafter described. 



Dr. KiDD observes, -f 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 

 precipitation take place upon saturating the acid with am- 

 monia.'' 



Mr. Chamberlain states, J that sulphuric acid probably 

 decomposes naphthaline, for that it holds but a very small 

 quantity in solution. The true interpretation of these facts 

 and statements will be readily deduced from the following 

 experimental 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 sublimation and pressure, was pulve- 

 rised ; about one part with three or four parts by weight of 

 cold sulphuric acid were put into a bottle, well shaken, and 

 left for 36 hours. The mixture then contained a tenacious 



* Quarterly Journal of Science , viii. 289, 18 19. 

 f Philosophical Transactions, 1 821, p. 216. 

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



