214 Mr, Faraday on the Mutual Action, S^c, [Sept. 



of offering an account of his experiments to the Royal Society, 

 and as regards date they precede mine. 



It may be observed, that the existence of sulphuric acid in 

 the new compounds is assumed, rather than proved ; and that 

 the non-appearance of sulphurous acid, when sulphuric acid and 

 naphthaline act on each other, is not conclusive as to the non- 

 reaction of the bodies. It is possible that part of the hydrogen 

 of the naphthaline may take oxygen from one of the proportions 

 of the sulphuric acid, leaving the hypo-sulphuric acid of Welter 

 and Gay-Lussac, which, with the hydro-carbon, may constitute 

 the new acid. I have not time at present to pursue these refine- 

 ments of the subject, or to repeat the analyses which have been 

 made of naphthaline, and which would throw light upon the 

 question. Such a view would account for a part of the overplus 

 in weight, but not for the excess of the sulphuric acid obtained, 

 above two proportionals. 



The glowing salt of baryta was now analysed by a process 

 similar to that adopted for the flaming salt. The specimen 

 operated upon was pure, and in a distinctly crystalline state. It 

 had been heated to about 440° F. for three hours in a metallic 

 bath. Ten grains of this salt exposed to air for 40 hours 

 increased only 0*08 of a grain in weight. These when converted 

 into sulphate of baryta by heat and sulphuric acid, gave 4*24 

 grains. Seven grains by carbonate of baryta, oxide of copper, 

 heat, &c. gave 6*02 grains of sulphate of baryta: hence 10 grs. 

 of the salt would have afforded 8*6 grains of the sulphate, equiva- 

 lent to 2*915 grains of sulphuric acid. Five grains, when heated 

 with oxide of copper, gave 16*68 cubic inches of carbonic acid 

 gas, equal to 7*772 grains, and equivalent to 2*12 grains of 

 carbon. The water formed amounted to 1*2 grain equivalent to 

 0* 133 of a grain of hydrogen. 



From these data, 100 grains of the salt would appear to 

 furnish 



Baryta 28*03 . . 78*0 or i proportional. 



Sulphuric acid 29*13 .. 81*41 nearly two proportionals. 



Carbon 42*40 . . 118*0 approaching to 20 ditto. 



Hydrogen . . .-. 2*66 . . 7*4 or 74 proportionals : 



102*22 



results not far different from those obtained with the former salt. 

 I have not yet obtained sufficient quantities of this salt in a 

 decidedly crystalline state, to enable me satisfactorily to account 

 for the difference between it and the flaming salt. 



Attempts were made to form similar compounds with other 



