the Paraffins and their Derivatives. 217 



Where, however, as in the case of the more complex suc- 

 ceeding terms, isomerism does or may occur among iso-acids 

 with one another, and among neo-acids with one another, these 

 relations of derivation are confined to certain isomeric forms 

 only, as instanced in the case of the four acknowledged forms 

 of isocaproic acid, the first two forms only being derivable as 

 above from the two 5-carbon pseudols each to each, and the 

 last two deriving from the two 5-carbon iso-primary alcohols 

 each to each, by the substitution, as before, of oxatyl for hy- 

 droxyl, thus : — 



PropyUmethyl-acetic Acid. 



(C0 2 H (OH , 



HC^C 3 H 7 from HC^ C 3 H 7 or HO.HO^ 



(CH 3 (CH 3 <■ 



C 3 H 7 



Diethyl-acetic Acid. 



HC {(5 2 4 from MccV « h( >- ho {o:Ii- 



Ethyl-methyl-propionic Acid. 



.00 2 H 

 HC^OoH, from HC 



\ C 2 H 5 . 

 (CH 3 



Dimethyl-butyric Acid. 

 H0 |C 6 ^O 3 H from H0{<g£H 



Similarly, as regards the derivation of the succeeding from 

 the preceding alcohols by indirect exchange of CH 2 (OH) for 

 OH, it may be noticed in the Table of alcohols proper that 

 while the first isoalcohol or isobutyl alcohol is derivable, as 

 above, from the pseudopropylic or first secondary alcohol, but 

 one of the two conceivable isopentyl alcohols would be deri- 

 vable in this way from pseudobutyl alcohol, the other being 

 derived instead from primary isobutyl alcohol. 



