442 Dr. Kane on the Composition of certain Essential Oils. 



lower than the general mass subsequently condensed, I ob- 

 tained the following result : 



Material = 0*337 gramme gave 



Hence per cent 



Water = 0*360 



Carbonic acid = 0*969 



Carbon = 79*53 



Hydrogen = 11*86 



Oxygen = 8*61 



This result might be considered as approximating to that of 

 Blanchet ; but this portion could not be considered as being 

 pure oil, as it constituted not a tenth of the quantity submitted 

 to distillation. I attributed its different composition to an 

 adulteration by oil of turpentine, which from its greater vo- 

 latility came over in the commencement. If the oil of tur- 

 pentine were in large quantity, a complete rectification could 

 not be obtained. 



Upon the whole, it is evident, that we cannot consider the 

 nature of the oil and stearopten of peppermint as being ab- 

 solutely determined; at the same time, I conceive myself 

 justified in placing some confidence in my results, from their 

 agreement, and the care with which the substance had been 

 purified. 



IV. Oil of Pennyroyal. — {Mentha Pulegium.) 

 The oil of pennyroyal is stated by Mr. Brande to have a 

 specific gravity of 0*939. I could not obtain it in commerce 

 with a specific gravity higher than 0*9271. I consider, how- 

 ever, the specimen having that specific gravity as being pure, 

 and that a higher density arises from dissolved stearopten. 

 The oil of 0*9271 having been rectified, left but little solid 

 matter ; and the pure oil after distillation had a specific gra- 

 vity of 0*9255. Its boiling point could not be obtained quite 

 constant, fluctuating between 360° and 370° Fahr. At the 

 end of this paper a few remarks on the boiling points of these 

 oils will be found. It was analysed as follows : 



A. Material = 0*3607 gramme gave 



Water = 0*353 



Carbonic acid = 1*020 



B. Material = 0*30 14< gramme gave 



Water = 0^^297 



Carbonic acid = 0*861 



Hence per cent. 



A. 



Carbon = 78*2 



Hydrogen = 10*8 10-9 ^ 100*0 



Oxygen = 11*0 



