MR. BRODIE ON CEROTIC ACID. 
157 
experiments showed that it approached inargaric acid in its constitution : but I have 
never been able to procure the quantity necessary to its sufficient purification, and 
the analyses led to no conclusions as to its formula which deserve to be recorded. 
It is a matter of interest to know in what proportions, relative to its other con- 
stituents, the cerotic acid is contained in the wax. This may readily be determined 
by precipitating by acetate of lead the solution of a known quantity of wax and de- 
termining the quantity of the lead salt produced. It is necessary however, in order 
to know to what quantity of acid in the wax the found quantity of lead salt corre- 
sponds, to know the atomic weight of the lead salt itself. There is great difficulty in 
washing out this lead salt so as perfectly to remove from it the rnyricin. In order 
therefore to effect any satisfactory purification of it, I was obliged to operate on a 
smaller quantity of the salt than I should otherwise have chosen. My experiment, 
however, was sufficient to show that the salt is the neutral salt containing one equiva- 
lent of lead. 
0T445 grm. of the lead salt gave when ignited 0 032 grm. of solid residue. This 
residue, extracted with acetic acid and dried, left 0*0065 grm. of residue, and lost 
0'0255 grm., which, reckoned as oxide, contains 0*0236 grm. lead. This gives 0*0296 
as the whole quantity of lead in the salt. Reduced to parts per cent, this gives 20*48 
as the per-centage of lead. The formula C54 H53 Og-f-PbO requires 20*26 per cent. ; 
this therefore is the formula of the salt. 
To determine the proportion of the acid in the wax itself, a portion of pure yellow 
wax was dissolved in ether and filtered from adhering impurities, then dissolved in 
naphtha-ether and precipitated by acetate of lead dissolved in alcohol ; an additional 
portion of ether was afterwards added to ensure the entire precipitation of the salt, 
the solution was filtered hot, and the lead salt was carefully washed out on the filter. 
1*0905 grm. of wax treated in this manner gave 0*301 5 grm. of the lead salt, which, 
assuming it to be the neutral salt, is equivalent to 0*24 grm. of the acid C54 H54 O4. 
This reduced to parts per cent, gives 22*0 of the cerotic acid in every 100 parts of 
bees’-wax. 
Although this was the proportion of cerotic acid in the bees’-wax I had prepared, 
it by no means followed that other specimens of wax when examined would give a 
similar result. Various chemists have stated that the proportions of the cerin varied 
in different specimens of wax ; and although the estimate of the cerin was a mere 
matter of guess, no criterion of its presence or absence being known, yet neverthe- 
less the great difference in the results of the different chemists who have attempted 
to determine this point led me to suspect that the quantity of the cerotic acid in the 
wax did in truth vary ; and that it might be possible, if so, to find a wax which even 
did not contain this body. I have found this acid in all the bees’-wax made in this 
part of the world, bleached or otherwise, which I have examined*. It occurred to me 
* I should except a wax made by wild bees in Wiltshire, which I tested with acetate of lead for this acid, 
but could find none. The quantity of the wax however was so small that I was unable to make many experi- 
ments with it. 
