Dr. Kane 07i the Composition of certain Essential Oils. 4*37 



Society, and will be printed in the Transactions of that 

 body. Beheve me, 



My dear Sir, yours sincerely, 

 Clapham Common, Oct. 19, 1838. JoHN P. Gassiot. 



Note on the preceding Communication, hy Mr. Bray ley. 



On the 20th of October I had the pleasure of witnessing the 

 remarkable and hitherto I believe unnoticed difference in the 

 temperature of the positive and negative electrodes, which is 

 described by Mr. Gassiot in the preceding communication; that 

 gentleman having then repeated the experiment many times, 

 in the presence of Professors Faraday and Daniell, Jonathan 

 Pereira, Esq., F.R.S., and myself. It having been suggested 

 that the effect might be due to the particular metal of which 

 the electrodes were formed, Mr. Gassiot afterwards changed 

 the copper wires usually employed, successively for wires of pla- 

 tinum, iron, steel, and brass, when the same phaenomenon 

 was exhibited in each instance, proving it to be due to a 

 cause primarily connected with the activity of the pile. 



LXII. On the Composition of certain Essential Oils. By Ro- 

 bert Kane, M.D., M.R.I.A., Sfc. Sfc. ^c* 



nPHE analyses, which constitute the material of this paper, 

 ^ were undertaken as the first step in a train of research, 

 which had for its object the solution of two problems in organic 

 chemistry, the importance of which will be at once recognised ; 

 namely, first, whether there exists a law connecting the com- 

 position of the oils derived from the same natural family of 

 plants ? and secondly, what is the chemical nature of the 

 essential oils as a class ? is the oil of bitter almonds a type for 

 all ? Towards a decision of these questions some materials 

 have been collected ; but the investigation embraces a field 

 so wide, that considerable time must elapse, before even such 

 general results, as have been already obtained, can be worked 

 into a form fit for publication. In the meantime I am in- 

 duced to lay before chemists those conclusions with respect 

 to the composition of some of the oils, which may serve as 

 data in a solution of the first question, and as initiatory to the 

 more abstract considerations on their composition as a class. 



I. Composition of Oil of Rosemary. 

 The oil of rosemary, obtained in its purest commercial 

 form, is colourless, and possesses strongly the odour of the 



* Communicated by the Author. 



