46 M. Kolbe on the Constitution of the Fatty Acids. 



possible to replace directly the oxygen in carbonic acid by 

 hydrogen and bodies allied to it, and so give rise to the forma- 

 tion, not indeed of sugar, but of bodies immediately derived from 

 it. In Wanklyn's discovery of the transformation of carbonic 

 acid into propionic acid and into acetic acid, the view that the 

 fatty acids, the alcohols, acetones, aldehydes, &c, are simple 

 derivatives of carbonic acid, finds its chief support. 

 Kolbe writes the formula of anhydrous carbonic acid 



C 2 4 =C 2 2 ,0 2 , 



in which two atoms of oxygen are supposed to exist outside the 

 radical carbonyle. If in carbonic acid one of the four oxygen 

 atoms is replaced by hydrogen, formic acid results ; and if three 

 atoms of oxygen are replaced by three atoms of hydrogen, 

 methylic alcohol is produced. A comparison of the formulae 

 shows these relations ; and it is to be remarked that when a 

 positive element replaces a negative, Kolbe writes it on the left 

 of the primary radical. 



2 HO, (C 2 O 2 ) O 2 HO, H (C 2 O 2 ) O 2 HO, (H 3 C 2 ) O. 



Carbonic acid. Formic acid. Methylic alcohol. 



By the replacement of one of its atoms of oxygen, the bibasic 

 carbonic acid is changed into the monobasic formic acid. 

 Similarly, by the replacement of an atom of oxygen by 

 methyle, ethyle, butyle, &c, we obtain the corresponding 

 acids HO, C 2 H 3 (C 2 O 2 ) 0, acetic acid ; HO, (C 4 H 5 ) (C 2 O 2 ) 0, 

 propionic acid ; HO, C 8 H 9 (C 2 O 2 ) 0, valerianic acid. In an 

 analogous manner, Kolbe derives from bibasic sulphuric acid, 

 the monobasic methylsulphuric acid and phenylsulphuric acid. 



2 HO, (S 2 O 4 ) O 2 Sulphuric acid. 



HO, C 2 H* (S 2 O 4 ) Methylsulphuric acid. 



HO, C 12 H 5 (S 2 O 4 ) Phenylsulphuric acid. 

 If in carbonic acid an atom of oxygen is replaced by an atom of 

 hydrogen, acetic acid results ; if a second atom of oxygen is re- 

 placed by a radical, we get the formula of an acetone. 

 HO, C 2 H 3 (C 2 O 2 ) Acetic acid. 



£j^3J(C 2 2 ) Acetone. 



If, in carbonic acid after an atom of oxygen has been replaced by 

 methyle, the second be replaced by chlorine, chloride of acetyle 

 results ; and if the second, third, and fourth atoms of oxygen 

 be successively replaced by hydrogen, we have the compounds 



C * ifl c * ° 9 ' aldeb y de > H0 > c * h 2 } C2 > °' alcoho1 ; ° 2 H 3 1 C * 



hydride of ethyle. 



