332 ODOROGRAPHIA. 



powdered iodine. When one or two drops of the liquid are 

 dissolved in about 50 drops of glacial acetic acid, and a drop of 

 concentrated sulphuric acid is added, it affords a pinkish colora- 

 tion, but not the handsome violet colour described by Wallach* 

 as characteristic of the sesquiterpene C^. H^^. This, however, 

 does not detract at all from the possibility of its having the 

 molecular composition C^o Hj^^, which the body in question 

 undoubtedly possesses, since oil of turpentine, as well as some 

 other similar oils, does not afford the above-described reaction. 

 These results serve to confirm the statement that a body corres- 

 ponding to theGaultherilen of Cahours is present in oil of Graultheria, 

 although in very much smaller amounts than has hitherto been 

 generally accepted. They also serve to prove that upon the 

 presence of this body depends the difference betw^een the oil of 

 Gaultheria and the oil of Sweet Birch : for, whatever may Ije the 

 varying character of these oils as found in commerce,! we are 

 convinced that the pure oil of Birch, as determined by Pettigrew,| 

 under the supervision of one of us (Power), consists of pure 

 methyl salicylate." 



According to the above mentioned observers, the sp. gr. of pure 

 oil of Birch is 1-1819 at 15^ C, and that of oil of Gaultheria 

 1'1759 at 15° C. Messrs. Schimmel have determined the sp. gr. 

 of Wintergreen oil at 1-189 at 10° C, 1-185 at 15°, and 1-182 at 

 20° C.,§ and more recently 1 1 caution buyers against oils of lower 

 sp. gr. less than 1-180, stating the sp. gr. of pure methyl salicylate 

 to be 1-1870 at 15° C. It is stated by PettigrewlF that a "pure 

 oil of Birch " was found by him to boil at 218° C. Power and 

 Werbke state that " an authentic specimen " of oil of Gaultheria 

 was found by them to " distil quite constantly at from 215° to 

 21 G° C." 



Cahours, in 1843,** found that methyl salicylate could 

 be prepared artificially by distilling a mixture of 2 parts of 



* Liebig's Ann. der Chemie, 1886, p. ST. 



t Siiuibb's Epliemeris, iii. (1887), p. 953. 



X Am. Journ. Pharm., 1883, p. 385. 



§ Bericht., April, 1887. 



li Bericht., October, 1890. 



*ii Am. Journ. Pharm., 1884, p. 266. 



** Ann. Chem. Pliarm., xlviii., p. 83, and liii., p. 327. 



