12 Researches on the Chemistry of the Camphoric Acids. [Dec. 5, 



H CHoCOOH 



\/ 

 C 



/ 



C 



/ \ 

 COOH H 



(dextro- and laevo-transcamphoric acid). 



On the other hand, Chautard's laevo-camphoric acid, being obtained 

 directly from a laevo- camphor, will have the respective groups on the 

 same side. 



'Nomenclature. 



We may adopt the nomenclature introduced by von Baeyer to dis- 

 tinguish the hydroterephthalic acids. Ordinary camphoric acid then 

 is dextro- and Chautard's acid laevo-ciscamphoric acid, the prefix c i 

 indicating that the carboxylic groups are on the same side of the ring 

 plane. 



The new acid again, which I have described in this paper, is the 

 laevo- and the acid yet to be discovered will be the dextro-transcam- 

 phoric acid, the prefix trans implying that the groups which govern 

 the isomerism are on opposite sides of the ring plane. 



It will be noticed that the formulae which I have adopted require 

 the existence of another series of two camphors (dextro- and laevo-) 

 and four camphoric acids ; but of the existence of these we have as 

 yet no evidence. 



[Postscript, Dec. 2nd, 1889. — Since the above was written, my 

 attention has been drawn to a paper by M. Friedel in the 4 Comptes 

 Rendus ' of last May, in which he describes a laevo-camphoric acid 

 obtained from the substance known for some time as mesocamphoric 

 acid. This laevo-acid appears to be the same as the one I have just 

 described, and the mesocamphoric acid to be a mixture of the laevo- 

 with the original dextro-acid. Thus mesocamphoric acid must no 

 longer be regarded as a distinct isomer.] 



