SYNTHETICAL EESE.\JICHES ON ETHEES. 



71 



radicals. When, however, we ascend the next step of the series, we find that butyric 

 acid is capable of two, and only two isomeric modifications, viz., 



(C Ho ( 



C Me2 H 

 CO Ho 



Ethacetic 

 acid. 



Dimethacetic 

 acid. 



Both these acids have now been Synthetically produced, and the first must be identical 

 with butyric acid, since they both contain ethylated methyl as their basylous radical — a 

 conclusion which is in perfect harmony with experimented facts, for we have shown above 

 that butyric acid and ethacetic acid are undistinguishable from each other, whilst meth- 

 acetic acid difiers in odour and in the crystalline form of its silver-salt. 



Ascending now to caproic acid, the number of possible isomers is augmented to eight, 

 this being in fact the number of possible metameric modifications of the basylous radical 

 of caproic acid — amyl, viz. : — 



IV. 



rEt 



dMe 



VII. 

 rC(CMe2H)H2 



c]h 



VIII 

 re Meg H 



c]Me 



[h 



No. I. is normal amyl or butylated methyl ; Nos. II., III., and IV. are obvious isomers, 

 whilst the remainder owe their differences to the metameric modification of the radicals 

 butyl and propyl contained in Nos. I. and II. 



Of the isomeric acids, those containing the radicals Nos. I. and III. are the only ones 

 known. The first is the caproic acid obtained by the action of potash upon amyl cyanide, 

 and which is probably identical with the caproic acid obtained from cocoa-nut oil ; whilst 

 the second is diethacetic acid obtained as above described, and which differs from caproic 

 acid in its odour, in the boiling-point of its ether (which is 11° C. lower than caproic 

 ether), in the specific gravity of its ether, and in the crystalline form and solubility of its 

 silver-salt. 



(Enanthylic acid admits of still more numerous isomeric modifications, of which only 

 one is at present known with certainty, since, for the reasons above given, we believe 

 amylacetic acid to be identical with the acid that would be obtained by the action of 

 potash upon hcptyl cyanide, and probably also with that obtained from castor oil and 

 other similar sources. 



Now, inasmuch as the acids obtained from the cyanides appear to be identical with 

 the natural or non-synthesized acids of the same atomic weights, and as the alcohol 



