Mr. Hennell on' the mutual Action of Sulphuric Acid, 8$c. 355 



that its elements were in some peculiar state of arrangement 

 in the oil of wine. 



To determine the quantity of sulphuric acid thus elicited, 

 I boiled 200 grains of very carefully prepared oil of wine, 

 free from all trace of acid, with a solution of caustic potassa 

 to dryness ; the residue was heated red hot and dissolved in 

 water, the excess of potash being slightly supersaturated with 

 dilute nitric acid ; muriate of baryta was then added as long 

 as it formed a precipitate, and 218*3 grains of sulphate of 

 baryta were thus obtained. A repetition of this experiment 

 gave the same results ; so that we may conclude upon the pre- 

 sence of 74 grains of sulphuric acid in 200 of oil of wine. 



In resuming the analysis of oil of wine by ignited oxide of 

 copper, I found it necessary to mix it perfectly with the greater 

 part of the oxide employed, otherwise, as in the first experi- 

 ment, sulphurous acid was formed in consequence of the per- 

 fect reduction of a portion of oxide, and the action of the 

 metal thus reduced upon the sulphuric acid. With this pre- 

 caution several experiments were performed, the results of 

 which were very uniform, and as follows : 2 '08 grains of oil 

 of wine carefully freed from all adhering moisture by quick- 

 lime, were properly mixed with 200 grains of oxide of copper, 

 and subjected with due precautions to a red heat, in the ap- 

 paratus formerly adverted to: the products were 8*8 cubic 

 inches of carbonic acid gas, and 1*54 grains of water, and 

 these are equivalent to 0*171 of a grain of hydrogen, and 

 1*118 grains of carbon : 100 grains therefore of oil of wine 

 would afford Hydrogen . . . 8*30 



Carbon .... 53*70 



62- 

 and the deficiency of 38 grains must be referred to sulphuric 

 acid, a conclusion which is verified by the former experiment 

 with solution of potassa, in which the proportion of that acid 

 is shown to be 37 per cent. We may I think therefore con- 

 clude the above estimate to be near the truth, and the results, 

 as respects the carbon and hydrogen, approximate nearly to 

 the proportional quantities 6 and 1. 



From the above experiment, however, we can only infer the 

 composition of the hydrocarbon, which is combined with and 

 neutralizes the sulphuric acid ; for in all the specimens of oil 

 of wine which I have examined, I have found a variable quan- 

 tity of hydrocarbon held in solution, part of which spontane- 

 ously separates in a crystalline form when it has been kept for 

 some time, or when exposed to cold, but the whole of which 

 I have not yet devised any means of separating ; this dissolved 



2 Y 2 hydro- 



