ON THE NOMENCLATURE OP ORGANIC COMPOUNDS. 135 



Laurent has proposed to give the termination se to those bodies which are 

 formed from a hydrocarbon by the substitution of some element for one or 

 more of the hydrogen atoms present in the original compound. To these 

 letters he prefixes one or other of the vowels, according to the number of 

 atoms so replaced, a being used when only 1 atom of the new ingredient is 

 introduced, e when 2 atoms, i when 3, and so on, till the whole number of 

 vowels is exhausted ; after which the series recommences by prefixing the 

 syllable al to the vowel. 



Thus, from naphthaline, C*^ H*, he derives, — 



Chlornaphthase C* H^ CI, 

 Chlornaphthese C^ H6 C% 

 Chlornaphthise C^ H* C*, and so on ; but 

 Chlornaphthalese is C^ H^ CP. 



Other refinements upon this mode of nomenclature are proposed in 

 M. Laurent's various papers, and well deserve the attention of those who 

 follow up similar tracks of research. 



The termination al has been appropriated to combinations into which 

 aldehyde enters as a constituent, or which are derived from that body. It 

 may be right, however, to point out, that many substances bound together by 

 a very loose analogy are thus embraced. 



Thus chlora/ is aldehyde in which the 3 hydrogen atoms are replaced by 

 3 of chlorine. C* H^ O + HO becomes C* Cl^ O + HO. 



Aceta^, on the contrary, is aldehyde united with oxide of ethyl. 



C* H* O' aldehyde 



C* H5 O' oxide of ethyl 



H' O' water 

 C8 H9 03 acetal 



whilst the analogous compound of aldehyde with ammonia is called simply 

 aldehydammonia. 



The term ethane, in like manner, comprises compounds of which ether 

 forms a part ; but it should be confined to those into which an acid does not 

 enter as a constituent, since in the latter cases the nomenclature of the salts 

 may be preferable. 



Thus urethane may be retained as the name for a compound of urea and 

 carbonic ether, or the carbonate of oxide of ethyl, its composition being — 



Urea C * H * O* N^ 



2 Carbonic ether. . C" H"> O^ 



Ci2Hi*08N« 

 But it would seem better to designate the substance called oxamethane, by 

 the term oxamate of oxide of ethyl — 



Oxamic acid. . C* H^ N' O* 

 Ether C^ H^ O^ 



C« H7 N' 06 



and oxamethylane by that of the oxamate of oxide of methyl. 



In this manner we shall also avoid the confusion that may arise between 

 names so related as oxamethylane and oxamethane, the former indicating 

 the oxamate of methyle, the latter that of ethyle. 



I am unable to attach any definite meaning to the termination an, by 

 which certain organic compounds connected with urea are now designated. 



Alloxan, one of them, is regarded as an acid, the erythric of Brugnatelli. 

 Murexan may probably be a salt of cyanoxalic acid and ammonia; but not- 



