Chemical Nature of Wax. 229 



It is a matter of interest to know in what proportions, rela- 

 tive to its other constituents, 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 determining 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 corresponds, 

 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 myricine. 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 equivalent of lead. 



0*1445 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 00236 grm. lead. This 

 gives 0*0296 as the whole quantity of lead in the salt. Re- 

 duced to parts per cent, this gives 20*48 as the per-centage of 

 lead. The formula C^ H^ O s +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 aether and fil- 

 tered from adhering impurities, then dissolved in naphtha- 

 aether and precipitated by acetate of lead dissolved in alcohol; 

 an additional portion of aether was afterwards added to ensure 

 the entire precipitation of the salt, the solution was filtered 

 hot, and the lead salt was carefully washed on the filter. 



1*0905 grm. of wax treated in this manner gave 0*3015 

 grm. of the lead salt, which, assuming it to be the neutral salt, 

 is equivalent to 0*24 grm. of the acid C M H^ 4 . 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 

 cerine varied in different specimens of wax ; and although 

 the estimate of the cerine was a mere matter of guess, no crite- 

 rion of its presence or absence being known, yet nevertheless 

 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 



