152 



Volatiliz ». 



Heatc 1 in a 

 retort. 



Solution in 

 water. 



Method of 

 purifying. 



OX THE SUBERIC ACID. 



Thrown on hot coals it is volatilized, without leaving any 

 residuum, and emitting a smell of suet. 



When heated in a small glass retort on sand, it melts like 

 fat with a gentle heat. If the retort be withdrawn from 

 the tire, and the melted acid diffused over its inside, it cry- 

 stallizes in needles by cooling. If the distillation be con- 

 tinued, it rises in vapours, which condense in the summit of 

 the retort in white needles, some of which are half an inch 

 long. This sublimate has all the characters of suberic acid. 

 A slight coally mark is left in the retort. 



Suberic acid dissolved in water reddens litmus very dis- 

 tinctly. It does not preceipitate lime *, strontian, or barytes 

 water, or the saline combinations of these bases. On eva-. 

 porating lime-water saturated with suberic acid, the calca- 

 reous suberate falls down in a white flocculent precipitate, 

 from which muriatic acid separates the suberic. This is 

 indeed an excellent method of obtaining it perfectly white. 

 The muriate of lime may be separated from it, by dissolving 

 it in a small quantity of hot water; when by cooling we 

 obtain the acid, which is always in a pulverulent form*f*> and 

 similar to what it was before being combined with the lime; 

 only this base takes from it the remains of the colouring 

 matter, which the water had not dissolved. 



Mistake of 

 Brugnatelli* 



* It seems to rpe, that Mr. IJrugnatelli must have deceived himself, 

 when he says, that suberic acid precipitates lime water, and all the 

 mineral calcareous salts. The oxalic acid, which no person has men- 

 tioned, and which is formed with the suberic acid, was no doubt the 

 occasion of the precipitate he obtained. It appears to me also, ou read- 

 ing the article suberic acid in Brugnatelh's Elements of Chemistry, 

 vol. II, p. 106, that the acid he describes still retains bitter matter, 

 resinous matter, and oxalic acid. 



\ I made this experiment, in order to see •whether the suberic acid 

 were analogous to the benzoic, and, in this case, to separate it from 

 the matter that prevented its crystallization. 

 Purification by I repeated the same experiment with barytes instead of lime, and 

 .arytej. ^ a< j tnp same resu it. The suberate of barytes is deposited by concen- 



tration, and its decomposition by muriatic acid afforded me the suberic 

 acid perfectly white. A small excess of the acid should always be em- 

 ployed, in order to separate the last portions of base, which the sube~ 

 ric acid might retain. 



Ammonia 



