34 THE BUTYRIC ACID GROUP. 



From the dry distillation of the baryta-salts of several of these 

 acids, substances isomeric with the aldehydes have been obtained. 

 They are known by the terminal syllable al ; they occur as oily, 

 very volatile, pungent fluids, which can be distilled without under- 

 going decomposition, dissolve freely in alcohol and ether, but not 

 in water, possess neither acid nor basic properties, are not so 

 easily converted into the corresponding acids by the action of the 

 atmosphere as by means of oxidising substances, and readily 

 exchange a portion of their hydrogen for chlorine. At present we 

 are acquainted with 



Butyral C 8 H 3 O 2 . 



Valeral C 10 H 10 O 2 . 



(Enanthal C 14 H 14 O 2 . 



Another series of derivatives is obtained from these acids by 

 heating their salts with strong bases, the acid losing the elements 

 of an atom of carbonic acid, and becoming converted into a sub- 

 stance which, in addition to a carbo-hydrogen polymeric with olefiant 

 gas, (but composed of an odd number of atoms,) contains 1 atom 

 of oxygen ; thus, for instance, Ca O. C 8 H 7 O 3 C O 2 ==:C 7 H 7 O. 

 These bodies are distinguished by the terminal syllable one ; they 

 are colourless and very volatile oils with a penetrating odour, readily 

 soluble in alcohol and ether, insoluble in water, very inflammable, 

 and not capable of combining with acids or bases. 



In these acids, as in many other organic bodies, certain 

 atoms of hydrogen may be replaced by the corresponding number 

 of atoms of chlorine, bromine, or iodine; thus, for instance, the 

 formation of chloracetic acid is explained by the equation 

 C 4 H 3 O 3 .HO + 6C1=:3 HC1 + C 4 C1 3 O 3 .HO. In butyric acid, 

 various numbers of atoms of hydrogen may be replaced by an 

 equal number of atoms of chlorine ; thus, we have two chloro- 

 butyric acids represented by C 8 (H 5 C1 2 )O 3 , and C 8 (H 3 C1 4 )O 3 . 

 However strongly Berzelius, even to the very close of his life, may 

 have contended against the substitution-theory, yet we must not 

 disregard it in the consideration of the constitution of organic 

 bodies. For although this mode of indicating the composition of 

 organic bodies containing chlorine is opposed to the electro- 

 chemical views that have hitherto prevailed in chemistry, it ought 

 not to be wholly rejected, since it is the mode of representing the 

 constitution of such bodies, which approximates most closely to 

 the empirical composition. It necessitates no rigorous adhesion 

 to the metaleptic views of Dumas and Laurent, if for the sake of 

 greater facility of enquiry, and a better comprehension of the 



