148 
MR. BRODIE ON CEROTIC ACID. 
lowing pages, I offer to the Royal Society are correct, their true chemical relations 
and constitution have been undiscovered. 
It would be useless, and it is by no means my intention, to comment upon all the 
ideas which other chemists have entertained upon this matter. There is however 
one theory, which has been advanced by certain chemists in France, of which it 
would be unbecoming in me to take no notice, both because it has a certain apparent 
amount of fact to support it, and because the originators of it, and others also, believe 
that they have finally settled the question of the true place which wax should hold 
in our classification of chemical substances*. M. Lewy has stated that cerin, that 
portion of the wax which is the more soluble in alcohol, is converted by oxidation by 
means of lime and potash into stearic acid. The method he pursued was that used 
by Dumas with such success for the conversion of alcohol into acetic acid; of 
potatoe oil into valerianic acid ; and for other similar transformations. He has ex- 
plained the reaction by giving to the cerin the formula Cgg Hgg O 4 . On this hypothesis, 
the cerin, by conversion into stearic acid, loses three equivalents of hydrogen and 
takes up three equivalents of oxygen into its constitution, the reaction being ex- 
pressed by the equation 
c„ H., Oi+3HO=C„ H^s 0, + H3= [ J ^ 
the cerin being considered the aldehyde of stearic acid. M. Gerhardt has taken 
up and extended this idea. Proceeding on the belief that the myricin and cerin are 
isomeric — a belief, I may observe, not justified by experiment, although almost 
universally adopted by chemists— he has stated that the myricin, of which by far the 
larger portion of the wax consists, corresponds to the metaldehyde of the same acid, 
and in a paper which he entitles, “ Faits pour servir a I’histoire de la cire des 
abeilles'l',” has explained on this hypothesis the origin of the products of the dry 
distillation of that substance. The theory of M. Lewy agrees sutficiently well with 
his analyses of the substances in question and with the relations of his formulae. I 
must however observe, that any person who will take the trouble of reckoning out 
those analyses on which the formula of stearic acid depends, according to the 
atomic weight of carbon now almost universally adopted by chemists, carbon 6 , 
hydrogen 1 , will see that this formula itself demands a new inquiry before we can 
accept it. These results of M. Lewy are in many ways at variance with my own 
experiments ; but I confess that if the agreement of the analysis and of the melting- 
point of the substance he obtained by oxidation of the cerin with the analysis and 
the melting-point of stearic acid were in truth a sufficient proof of the identity of 
the bodies, this difference in our results would be to me very difficult to explain. 
Wax certainly stands in a remarkable relation to fat, but I do not believe that rela- 
tion to be of the nature M. Lewy has conjectured, and I cannot but think that, in 
* Annales de Chimie, vol. xiii. p. 439 ; and Jahres-Bericht, Berzelius, vol. xxiv. p. 468. 
t Ibid. vol. XV. p. 236. 
