386 Mr. B. C. Brodie on the Chemical Nature 



The formula C^ H i53 O s + AgO requires — 



100*00 



There is a difference between the calculated and found 

 amount of silver of about 0*5 per cent, which I cannot doubt 

 arises from traces of cerotine still adhering to the acid, not- 

 withstanding all the pains I took to wash out the salt : for I 

 found that the amount of silver increased with the purification 

 of the acid by crystallization, even after I could find not the 

 slightest variation in the melting-point. The silver salt made 

 from an acid which was a part of the same original preparation 

 as the above and of exactly the same melting-point, but which 

 had not been so often crystallized, gave in two determinations 

 20*07 and 20*09 per cent, silver. It will be seen that the 

 formula I have given for the acid is confirmed by the analysis 

 of the acid obtained from distillation of the wax. 



Distillation of Cerotine. 



Cerotine requires a high temperature for its distillation. 

 The operation is accompanied with little explosions, owing to 

 the formation of a small quantity of water. The distillate is 

 perfectly colourless to the last, and solid, giving, when pressed 

 with blotting-paper, hardly a trace of oil ; it resembles in its 

 general appearance the cerotine itself, but has a lower melting- 

 point, about 70° C. 



The distillate also contains a larger per-centage of carbon 

 than the substance. A portion, melting at 73° C. and purified 

 by crystallization, gave to analysis carbon 83*20 and hydrogen 

 14-22 per cent.; but it is very difficult to raise the melting- 

 point much beyond 73° C. At first, from the constancy of 

 the melting-point, I was led to think that a new oxygen com- 

 bination had been formed. I found, however, afterwards that 

 the melting-point could be raised to 79° C. ; that is, the melt- 

 ing-point of the alcohol, a substance of a lower melting-point 

 remaining behind; and there can be little doubt but that part 

 of the cerotine distils over unaltered, while another portion 

 decomposes into solid hydrocarbon and water. I found, in 

 fact, that the amount of carbon diminished as the melting- 

 point was raised. 



