40 THE BUTYRIC ACID GROUP. 



Considering the subject in this point of view, we must regard 

 the acids of this group as constituted in the following manner : 



Formic acid ^hydrogen-oxalic acid= H. C 2 O 3 . 



Acetic acid =methy oxalic acid =C 2 H 3 . C 2 O 3 . 



Metacetonic acid ^ethyloxalic acid =C 4 H 5 . C 2 O 3 . 

 Butyric acid =metethy oxalic acid =C 6 H r C 2 O 3 . 

 Valerianic acid valyloxalic acid C 8 H 9 . C 2 O 3 . 

 Caproic acid =amyloxalic acid =C 10 H n .C 2 O 3 . 



Closely allied to this view of the constitution of these acids is 

 another consideration, which has reference to the production of 

 these homologous acids from the series of the ether-like, homolo- 

 gous haloid bases. The general formula of the haloid bases, oxide 

 of methyl, oxide of ethyl, and oxide of amyl, is=C n H n+1 O, while 

 the formula of the acids is C n H n _ 1 O 3 ; we have explained the pro- 

 duction of the acids from the corresponding haloid bases by the 

 simple assimilation of 4 atoms of oxygen, and loss of 2 atoms of 

 water; as, for instance, in the conversion of oxide of ethyl into 

 acetic acid : if, however, the above conclusions, which have been de- 

 rived from simple inductions, be correct, it must be assumed that 

 (to take a definite case) in the conversion of oxide of ethyl into acetic 

 acid, the complex atom, C 2 H 2 , leaves the'radical of the oxide of 

 ethyl, C 4 H 5 O, and unites with 4 extraneous atoms of oxygen, and 

 with the 1 atom which is present in oxide of ethyl, to form water 

 and oxalic acid, which combines with the radical of the next 

 lower haloid base, methyl, and represents acetic acid. 



Oxide of amyl yields valyloxalic acid : 



(C 10 H n )0 + 40=2HO+(C 8 H 9 ) C 2 O 3 . 



Oxide of valyl yields metethyl oxalic acid : 



(C 8 H 9 )0 + 40=2HO+(C 6 H 7 )C 2 3 . 



Oxide of metethyl yields ethyloxalic acid : 

 (C 6 H 7 )0 + 40=2HO + (C 4 H 5 )C 2 3 . 



Oxide of ethyl yields methyloxalic acid : 



(C 4 H 5 )0+40=2HO + (C 2 H 3 ).C 2 3 . 



As, according to this view, oxalic acid constitutes the acidify- 

 ing principle of the bodies of this group, we shall consider it the 

 first in the series of acids. 



