MR. BRODIE ON CEROTIC ACID. 
149 
his desire to establish this relation, he has rested content with insufficient proofs of 
his theory. Any person who has had a little experience in these inquiries, must know 
how deceptive this melting’-point and analysis are as criteria of the purity or identity 
of bodies. The separation of this class of substances by crystallization is difficult, 
and often the composition per cent, of two substances of entirely different chemical 
formulae will agree within the unavoidable errors of the method of analysis. The 
reasons will hereafter appear why I am justified in saying that, in the cerin which 
M. Lewy analysed, he did not work on a pure chemical substance ; and that conse- 
quently any theory founded on the reactions of this body must fall to the ground ; I 
believe that by more careful inquiry he might have procured that substance of a 
different melting-point and constitution to that which he found. I have also in vain 
searched the papers which M. Lewy and M. Gerhardt have published upon this 
matter, to find some account of the preparation and the analysis of a salt of this so- 
called stearic acid, an easy and satisfactory experiment, and one which alone, in the 
case of acids of such high atomic weight, can justify the chemist in pronouncing on 
their constitution. Until such a salt is made, I cannot but consider that the evi- 
dence is insufficient, that the remarkable oxidation in question has ever been 
effected. 
I propose to give to the Society, in three papers, the results of an investigation on 
the nature of wax. The present paper will contain an inquiry as to the constitution 
of the so-called cerin ; I mean that portion of the bees’-wax which is the more soluble 
in boiling alcohol. The second paper will treat of the chemical constitution of a wax 
from China, a substance which, although it considerably differs in its appearance and 
properties from bees’-wax, in the form in which it comes before us in nature, is never- 
theless, chemically speaking, closely analogous to that body. In a third paper I 
propose to consider the nature of myricin, the other constituent of the bees’-wax itself. 
I may here state, that to ensure the purity of the wax used in the following experi- 
ments, I prepared it myself from the comb. It was made by bees in the county of 
Surrey in the years 1845 and 1846. This wax I have always used for the first prepa- 
ration of a substance. For further experiment I have sometimes used wax procured 
in other ways. 
Cerotic Acid. 
If wax melting at about 62° or 63° Centigrade be treated with boiling alcohol, a 
considerable portion will be dissolved. If this operation be repeated, the quantity of 
substance dissolved the fifth or sixth time will be evidentlv less than that dissolved 
in the first operation. But however often this operation be repeated, there will 
always be a portion of wax dissolved. This fact alone might lead us to suspect that 
any absolute separation of these two portions of the wax, by boiling with alcohol and 
subsequent crystallization out of that liquid, was impossible. 
A partial separation can, however, be readily effected, and by this method a sub- 
