ON THE NOMENCLATURE OP ORGANIC COMPOUNDS. 129 



can be referred to this same class. They are analogous, indeed, to urea, if 

 this body be regarded as — 



Cyanate of ammonia C* N O + HO + NH^ 



but not to the alkaloids, if the latter be represented as replacements of hy- 

 drogen atoms by hydrocarbons. 



Alcohols. — The term alcohol, although applied to a number of bodies, 

 whose physical properties deviate widely from those of the substance which 

 it was originally meant to signify, is a convenient expression for a class be- 

 longing, chemically speaking, to a common type — whether we regard them 

 with Liebig as the hydrated oxides of a hydrocarbon ; with Dumas as dif- 

 fering from their respective ethers simply by the addition of a second atom 

 of water ; or with Gerhardt as a cluster of atoms, the arrangement of which 

 is unknown to us, but which possess in common the property of being meta- 

 morphosed into a carburet of hydrogen, by abandoning the elements of one 

 equivalent of water ; and into a monobasic acid, by the substitution of two 

 atoms of oxygen for two of hydrogen. 



Although not more than six or seven of such bodies have as yet been dis- 

 covered, there seems a probability that we may eventually be able to form as 

 many as shall be equal in number to the vegetable acids already recognized, 

 and hence a particular name for the class in general seems indispensable. 



Aldehydes. — I am not aware of any objection that applies to the next 

 class — that of aldehydes, which, designating in the first instance the substance 

 prepared by the abstraction of two atoms of hydrogen from wine-alcohol, is 

 intended to stand as a generic term for all bodies similarly constituted. 



It ought therefore, as it might seem, to take in the essential oil of bitter 

 almonds C* H^ O^ which by the addition of O^ is converted into benzoic 

 acid, as .well as the analogous compounds derived from salicine, from cinna- 

 mile, and from cuminile, each of which gives rise to a corresponding acid. 



Thus, essential oil of — 



Almonds C* H^ O^ + O^ produces Benzoic acid. 



Spirsea O*Yi^"-0* + 0^ „ Salicylic acid. 



Cinnamon.. ..C'8H»6 02 + 02 „ Cinnamic acid. 

 Cumin C^o H^-* O^ + O^ „ Cuminic acid. 



In none of these cases, however, have the corresponding alcohols been 

 discovered, and hence it will be seen that in Turner's Chemistry they are 

 referred to the class of hydrurets, being considered as compounds of the or- 

 ganic radical, benzoyle C"H*0-, with 1 of hydrogen. The chemist, how- 

 ever, will have to take his choice of these two views, for he cannot without 

 confusion adopt both ; aldehydes in one sense being hydrurets, and hydru- 

 rets in another putting in a claim to be regarded as aldehydes. 



Ethers. — I next proceed to the class called ethers, a name originally ap- 

 plied to the peculiar volatile fluid produced by the action of sulphuric acid 

 upon wine-alcohol. Here, however, a considerable confusion has been 

 created by placing under the same head bodies connected together by a very 

 vague analogy. 



Whether, indeed, we regard sulphuric ether as the oxide, or as the hydrate 

 of a hydrocarbon ; or whether, discarding theory, we simply state it as 

 the product of the union of an alcohol with an acid, accompanied by the 

 elimination of the elements of water ; it will be found that this generic term 

 has been extended beyond the strict limits of its definition. 



Chemists, indeed, in general seem to consider it sufficient to place all those 

 bodies, the basis of which is an ether, under the head of compound ethers ; 



1851. K 



