356 Mr. Hennell on the mutual Action 



hydro-carbon, however, as future experiments will show, ap- 

 pears to be composed of single proportionals of its elements ; 

 we must therefore have recourse to other experiments to de- 

 termine the actual weight of hydrocarbon in its neutral or 

 atomic compound with sulphuric acid. 



Having thus far made out the composition of oil of wine, 

 I examined more carefully what had taken place during its 

 action upon heated solutions of muriate of baryta and potash ; 

 in which case, as I have already observed, an acid had been 

 formed not capable of precipitating baryta. 



200 grains of oil of wine were placed in a flask with 5 or 

 6 ounces of water, and the flask set in a vessel of boiling wa- 

 ter for an hour ; precipitated carbonate of baryta was then 

 added, and immediately dissolved with effervescence; about 

 90 grains of carbonate were required to neutralize the acid 

 formed : the solution filtered and set to evaporate soon be- 

 came acid, and sulphate of baryta precipitated. 200 grains 

 more of oil of wine were treated in the same way, but instead 

 of evaporating the baryta solution, it was precipitated by 

 carbonate of potash; the potash solution evaporated at a 

 temperature of 150° until it crystallized, remained perfectly 

 neutral ; the crystals were thin plates, not unlike chlorate of 

 potash, greasy to the touch, very soluble in water and alcohol, 

 burning when heated with a flame like that of aether, and 

 leaving an acid sulphate of potash. A few grains of these 

 crystals were heated in a tube, when they fused, swelled up, 

 and gave off a dense white vapour, which condensed into an 

 oil-like fluid, smelling strongly of sulphurous acid ; the resi- 

 duary salt was an acid sulphate of potash. 



The following experiments were now undertaken with a 

 view of more accurately determining the composition of this 

 crystalline salt. 



20 grains of the crystals being heated to redness, left 10*56 

 grains of sulphate of potassa, equal to 4*8 sulphuric acid, 

 5*76 potash. 20 grains were dissolved in a solution of caustic 

 potash, boiled to dryness, heated red hot, when cold dissolved 

 in distilled water, the excess of potash saturated by nitric 

 acid, and the solution added to one of muriate of baryta ; 28 

 grains of sulphate of baryta were obtained, very nearly equal 

 to 9*6 sulphuric acid ; the salt therefore contained twice the 

 quantity of sulphuric acid 'required to form a neutral sulphate 

 with the potash, or two proportionals. 



In order to ascertain the proportions of the remaining ele- 

 ments of the salt, 5 grains were heated with oxide of copper, 

 5'5 cubic inches of carbonic acid gas, and 14 grains of water 

 were collected ; several of these experiments were made with 



similar 



