240 Nature of the Jcid obtained by distilling Alcohol, 



of these acids which bestows upon it its peculiar disoxygenising 

 qualities. 



3. Nature of the Acid obtained by distilling Alcohol, Peroxide 

 of Manganese, and Sulphuric Acid. — There is still another acid 

 liquid, respecting the nature of which, the opinion of chemists has 

 been divided; and which I have found to have an analogous com- 

 position with those already examined. After Dobereiner had made 

 his interesting discovery, that formic acid might be obtained in 

 a state of purity, by the action of sulphuric acid and oxide of 

 manganese on tartaric acid, it is well known, that Gmelin ap- 

 plied the same process to several other organic products, such 

 as sugar, starch j &c. * with an analogous result. Amongst these 

 substances was alcohol, by distilling which with sulphuric acid 

 and peroxide of manganese, he obtained an acid hquid which 

 he regarded as formic acid. This liquid has lately been exa- 

 mined by Dobereiner, who, it would appear, maintains that it 

 contains no formic acid, and consists only of acetic acid, and a 

 portion of a volatile and pungent oily matter-)- . By similar 

 processes with those already described, I have, however, ascer- 

 tained, that formic as well as acetic acid enters into its composi- 

 tion. When saturated with magnesia, crystals of formate of 

 magnesia were in due time deposited, surrounded with the de- 

 liquescent acetate ; and when saturated with carbonate of lead, 

 evidence was obtained of the existence of a prismatic salt, of less 

 solubility than the acetate of lead. When the acid liquid was 

 concentrated by saturation with an alcali, and redistillation with 

 sulphuric acid, and was then heated with peroxide of mercury, 

 effervescence ensued, and on cooling, deposition of protoacetate 

 of mercury. These experiments, I conceive, establish the com- 

 position of this acid liquid to be quite analogous to the others 

 which have been the subject of examination. The oily matter 

 which, according to Dobereiner, is contained in it, can only, I 

 > should conceive, be viewed as an accompaniment not essential to 

 the constitution of the acid liquid. 



It seems also extremely probable, that it will be found that 

 the acetic acid prepared by Dobereiner, in his apparatus for con- 



• Poggend. Annalen. xvi. 55. f Ibid. xxiv. 607. 



