1^0 ON THE SUBERIC ACID. 



abate, I poured the matter still hot into a poTcelain cap- 

 sule, where I finished the evaporation with a gentle heat, 

 stirring it coutiijually. As soon as it was reduced to the 

 consistence of an extract, I put it with some water into a 

 large glass phial on. a sand heat. At the end of a few hours 

 I withdrew it from the lire; and on cooling two solid sub- 

 stances separatee. One of these, which I shall call A, 

 sunk to the bottom in the form of large flocks : the other, 

 B, congealed on the surface of the liquor like wax. This 

 I removed with a piece of card ; the other I separated by 

 filtration. 

 Examination The flocculentprecipitate, A* was insipid; insoluble in 

 of the matter wa t er anc [ m alcohol; and of a white colour, but turning a 

 little brown on exposure U tjjfe air. Nitric acid at 32° did 

 not act on it perceptibly. Placed on a red hot coal, it 

 burned without swelling up, and emitted a pungent smell 

 of empyreumat; ,.,ar. Its coal was bulky, and pretty 



hard. This substance therefore was nothing but the woody 

 part naturally contained in the cork. 

 Examination The supernatant substance, B, had very little taste. It 

 «f the matter ^ humble in water; but boiling; alcohol dissolved it, 

 some portion of woody matter exceptecj. The filtered so- 

 lution on cooling let fall a white substance resembling wax. 

 This being separated by a second filtration, I added water 

 tb the solution, which threw down a straw coloured resinous 

 substance, that turned reddish by exposure to the air, and 

 was add, notwithstanding I had washed it repeatedly. On 

 distillation it yielded a sort of concrete fat, and a very acid 

 fluid, that precipitated acetate of lead. I could not as- 

 certain its nature from the smallness of its quantity. 



The water that had been employed to precipitate the 



resin acquired a yellow colour by evaporation, and a taste 



jfes*embHng that of bitter almonds. It contained only a 



little of the yellow matter, and probably a few atoms of 



prtissic acid. 



E**min,tion The fluid from which'the matter A had been separated 



^the fluid ne- jjad an ac id an *d hitter taste ; precipitated lime water and 



**«*»tter A. calcareous salts ; turned solution of indigo green ; contained 



* little' iron, as appeared on the addition of galls; and, 



when the excess of acid was saturated, it did not precipitate 



gelatine, 



