Intelligence and Miscellaneous Articles. 157 



The authors now cited have found this same acid as one of the re- 

 sults of the destruction of hj'drocyanic aether, by means of potash. 

 M. Ncellner had also observed in the matters to which the fermenta- 

 tion of tartrate of lime gave rise, a peculiar acid, resembling acetic 

 acid, which on this account he named pseudo-acetic acid. M. Nickles 

 has submitted this acid to rigid experiments, which show that it 

 possesses the same composition as metacetonic acid ; and some in- 

 ferences induce him to suppose that it has a certain tendency to sepa- 

 rate into butyric and acetic acid ; hence the name of butyro-acetic 

 acid, by which he proposes to distinguish it. M. Nickles insists in 

 his memoir on some facts which he regards as sufficient to constitute 

 an essential difference between his acid and metacetonic acid; he men- 

 tions several properties which he thinks sufficient to separate them ; 

 but these properties are evidently owing to the still imperfect history 

 of metacetonic acid. On comparing metacetonic acid extracted from 

 metacetonate of potash, with that prepared by means of hydrocyanic 

 aether and butyro-acetic acid derived from fermented tartrate of 

 lime, the authors ascertained that they were identical, having the 

 same composition expressed by C^ H^ O* ; they have the same odour 

 and appearance ; they both crystallize at common temperatures in 

 laminae analogous to those which are yielded by acetic acid. They 

 combine with water in all proportions, the compound floating in the 

 form of an oily stratum on a solution of phosphoric acid or of chlo- 

 ride of calcium ; they both boil at about 284° F. ; their salts act in 

 the same manner ; when distilled with arsenious acid they yield pro- 

 ducts which have the odour of alcarsine ; the salts of silver which the 

 two acids form, are identical both in apjiearance and in composition. 



M. de la Provostaye determined that the crystals of the metaceto- 

 nate and butyro-acetate of barytes were similar in form, and that all 

 the angles which could be compared were identical. 



From the collection of facts now stated, the authors think they 

 are entitled to conclude that metacetonic acid, pseudo-acetic acid, 

 and butyro-acetic acid constitute the same and one only acid. 



This acid, they further remark, is the first which exhibits the fatty 

 character, setting out from formic or acetic acid, towards the fatty 

 acids properly so called ; it is the first which separates from solution 

 in the form of an oily stratum ; it is the first which gives, with the 

 alkalies, salts that are unctuous to the touch, similar to alkaline 

 soaps. These characters have induced the authors to give to this 

 substance the name oi propionic acid, a name which indicates its place 

 in the series of fatty acids ; it is the first of them. 



When one of the authors indicated, six years since, the existence 

 of a group of acids having the general formula C" H" O*, he could 

 cite only eight acids which were susceptible of being referred with cer- 

 tainty to this general formula ; they were the formic, acetic, valeri- 

 anic, ccnanthylic, lauric, myristic, ethalic and margaric. To reduce 

 the butyric, caproic and capric acids to this general formula, it was 

 requisite to admit a slight inaccuracy in the explanation of the gene- 

 rally correct analyses of M. Chevreul. Recent researches on these 

 three acids have perfectly confirmed this supposition. 



