M. H. Bleibtreu on Cumarine. 483 



According to the experiments of Delalande the formula of 

 cumarine is C 18 H 7 4 , giving the following per-centage, which 

 I compare with the mean of his analyses calculated with the 

 new atomic weight of carbon : — 



Theory. Mean of Delalande's 



, * 1 experiments. 



C 18 = 1350-00 73*47 72-91 



H 7 = 87*50 4-76 4'73 



4 = 400-00 21-77 



1837-50 100-00 



The results of my analyses approach near enough to those 

 of Delalande to prove the identity of cumarine and the sub- 

 stance obtained from the Asperula odorata. A comparison 

 however of the amount of carbon and hydrogen shows, par- 

 ticularly in the former, a sufficient deviation to throw a doubt 

 on the absolute number of equivalents. The circumstance 

 likewise of the near agreement, nay even of the excess of the 

 quantity of hydrogen calculated over that obtained in the 

 mean of Delalande's experiments, whilst in analysis the re- 

 verse is always the case, gave me grounds to doubt the cor- 

 rectness of his formula, and induced me to repeat the inves- 

 tigation of cumarine obtained from the Tonka beans. 



Preparation of Cumarine from Tonka Beans. 



The following appeared to be the best method of preparing 

 cumarine from the Tonka beans. 



The beans, finely cut or pounded, were digested for some 

 time with strong alcohol. The syrupy mass remaining after 

 distilling off the alcohol, becomes on cooling for the most 

 part a solid magma of crystals of cumarine, which can be 

 easily purified by treatment with animal charcoal and repeated 

 crystallizations. By proceeding in this manner it is more 

 easy to separate a fatty oil, which is contained in considerable 

 quantity in the Tonka bean. This body is colourless, and 

 without any characteristic odour, soluble in aether, insoluble 

 in alcohol and water, and possesses the property of dissolving 

 cumarine in considerable quantity. 



The process of treating the beans with aether, or directly 

 extracting the cumarine by boiling in water, is much inferior, 

 as the greater part of the oil is also removed with it, and can 

 afterwards only be separated with difficulty. In the fresh 

 bean the cumarine appears to be contained in solution in this 

 oil, from which it gradually separates in the form of pure 

 white crystals, and is found collected particularly between 

 the cotyledons and on their surfaces under the skin. 



