■ON THE SUBERIC ACID. 151 



gelatine, consequently contained none of the tannin of Mr. 

 1 latch ett. 



In evaporating the fluid with a gentle heat, it emitted a 

 pretty decided smell of vinegar. This induced me to finish 

 the evaporation in a retort; but 1 obtained only nitric acid, 

 without any acetous. Whether this were dissipated at the 

 commencement, or its quantity were too small for me to 

 detect it, I cannot say. The liquor, after evaporation and Suberic acid, 

 cooling, let fall an acid sedimentai 'matter, which T separated 

 by nitration. Four succcessive evaporations afforded me 

 fresh acid. After the fifth evaporation I obtained crystals , 

 of oxalic acid. Having decanted the mother water, which 

 was yellow, and had a very bitter taste, I precipitated the 

 oxalic acid it still retained by lime water in excess, and dis- 

 tilled it. The liquid that came, over into the receiver con- 

 tained a little ammonia, 1 then precipitated the liquid left 

 in the retort by carbonate of potash, and lime was thrown 

 .down. The filtered liquor yielded in a couple of days some 

 small gold coloured crystals of the bitter yellow matter com* 

 bined with potash *. 



This acid sedimentai matter was the suberic acid. I 

 washed off with cold water part of the yellow matter that 

 coloured it, and completed its purification by repeated so- 

 lution in boiling water, from 'which it separated by cooling 

 in little white flocks. By concentrating the bitter waters 

 J separated that, which they held in solution. By this pro- 

 cess I obtained a very white acid, about five parts of which 

 were obtained from sixty of cork. 



The suberic acid is as white as starch. It has an acid Properties of 

 taste, without any bitterness. Light does not alter its aci ^ 

 whiteness. To dissolve one part of this acid requires 38 

 parts of water at 60° [140° F.], and 80 parts at 13° [554° F.]. 

 Its little solubility prevents us from having it crystallized; 

 so that when it is dry it is always pulverulent and opake. 



* Having saturated the mother water of these crystals with muri- 

 atic acid, I obtained a precipitate, which exhibited all the character 

 istics of benzoic acid : but 1 dare not venture to assert, that this acid 

 is constantly formed, for in three operations on cork I obtained it but 

 once, and then in a very small quantity. 



Thrown 



J 



