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



and of a thick consistence. By repeated distillations it can be rendered com- 

 pletely pure. 



Its specific gravity is then from 0.8854 to 0.8875. Berzelius states the 

 specific gravity of the pure oil to be 0.889. It boils at a temperature from 332° 

 to 334° Fahr. Its boiling point is almost absolutely constant, — indeed much 

 more constant than that of any other oil I have examined. It was analyzed in 

 the ordinary way by combustion with oxide of copper, and the carbonic acid 

 collected, by potash, in Liebig's apparatus. 



A. Material = 0.300 gramme, gave 



Water = 0.315 



Carbonic acid = 0.907 



B. Material = 0.247 gramme gave 



Water = 0.261 



Carbonic acid = 0.744 



These analyses, having been made with quantities of oil distilled at different 

 times, and coinciding so completely, rendered it unnecessary to increase the 

 number. 



The above result is fully expressed by the formula c^j n^g o^, which gives 



c,5 = 276.3 83.63 



H38 = 38.0 11.54 



o, = 16.0 4.83 



330.3 100.00 



Evidently c^^u^o^ ^= 9{c^u^)-\-2uo; that is, we may consider oil of 

 rosemary as a hydrate of one of those numerous oils, agreeing in per-cent compo- 

 sition with oil of turpentine. This relation induced me to make some experi- 

 ttifents on the action of various bodies on it, the results of which belong properly 

 to a future memoir, but of which I shall transcribe one here. 



When mixed with sulphuric acid, oil of rosemary becomes black, and neutralized 



