On the Production and Nature of Oil of Wine, 97 



resemble Naptlialine ; they are soluble in ether and alcohol, and 

 crystallize from both those solvents in very slender prisms ; they 

 melt with a very slight heat, and sublime unaltered ; in warm 

 sulphuric acid they dissolve, forming a pink solution ; they dis- 

 solve in cold nitric acid, forming a deep red solution, similar to 

 that of morphia in nitric acid ; heat destroys this colour in- 

 stantly, and the solution, after boiling, on being diluted with 

 water, throws down a white flaky precipitate. The crystals are 

 insoluble in muriatic and in acetic acids, and in the caustic al- 

 kalies, hot or cold. 



The oil is soluble in ether and alcohol, but insoluble in water ; 

 distilled with water, it passes over like the greater number of the 

 essential oils, without having undergone any alteration ; but when 

 a portion was attempted to be distilled alone, the greater part came 

 over in the form of a thick oily matter, a considerable quantity 

 of sulphurous acid Avas formed, and charcoal and a little sul- 

 phuric acid were left in the retort. With a view to get rid of a 

 portion of acid, which the carbonate of potash had apparently 

 not removed, some of the oil was heated in a solution of caustic 

 potash ; it diminished considerably in bulk, and became much 

 more viscid than before : it was separated from the potash solution 

 by the action of ether, and when the ether was distilled off, there 

 remained a yellow oil, with very little fluidity, which evaporated 

 entirely when heated, without any ajDpearance of decomposition 

 or evolution of sulphurous acid, and which, in a few days, con- 

 creted into a mass of prismatic crystals, having all the characters 

 of those before described. The potash solution evaporated to 

 dryness, afforded a residue somewhat like acetate of potassa in 

 appearance ; upon heating a few grains of it, it took fire, and 

 burnt with a flame resembling that of alcohol, and sulphate of 

 potash remained ; it dissolved in hot alcohol, and the solution 

 deposited, on cooling, crystals in the form of pearly scales ; in 

 short, it had those characteristics which have been ascribed to 

 sulphovinate of potassa ; I therefore consider oil of wine as a com- 

 pound of sulpliovinic acid, and the peculiar crystallizable oil 

 which I have described. 



Vol. XIX. H 



