II. ROSE GERANIUM OIL AND ITS SUBSTITUTES. 



In spite of the great advance made in the chemi>t ry of r^rritial oil.x 

 during the past decade, ample evidence can readily he collected to 

 show that this is as yet a tortile field for the adulterator. Many 

 kinds of manipulators are found, from the tyro who endeavors to 

 palm otf oil of French turpentine for oil of rue, and the distiller who 

 sprinkles his rose leaves with geranium oil before distilling, to the 

 chemist who is an abettor to the use of acetin and glycerin in volatile 

 oils for the purpose of increasing the apparent content of ester and 

 alcohol, respectively. 



By referring to the various price lists it will be found that the quo- 

 tations for the geranium oils vary from $12 per pound for the Spanish 

 to S2.25 for the Turkish oil; and ginger-grass oil, which is conceded to 

 be only another name for an inferior Turkish oil, sometimes highly 

 adulterated, is quoted at $1.10 per pound. Certainly here seems to be 

 a great opportunity for the clever manipulator, and aside from the 

 assistance of a well-trained nasal organ, let us see what are the proba- 

 bilities of detecting such adulteration. 



Rose geranium oil is a colorless, yellowish, greenish, or brownish 

 liquid, depending on the manner of distillation and storage, and has a 

 pleasant rose-like odor. Its specific gravity varies from 0.8878 to 

 0.9073; optical rotation in a 100 mm tube, 6 to 16; ester, calcu- 

 lated as geranyl tiglinate, varies from 8 to 42 per cent. All varieties 

 an> soluble in 2 to 3 volumes of 70 per cent alcohol, except the Span- 

 ish, which is rendered turbid by the presence of a small amount of 

 separated paraffin. The chief constituents are geraniol and citronellol, 

 the total content of which, both free and combined, varies from 60 to 85 

 per cent. The former usually exists in much the greater proportion. 



Turkish or Indian geranium oil, also known as palma rosa, Indian 

 grass oil, and rusa oil, usually closely resembles rose geranium oil in 

 physical appearance, solubility, specific gravity, and percentage con- 

 tent of alcohols and esters. In odor there is frequently a close resem- 

 blance and the optical rotation varies from +2 to 2. 



Ginger-grass oil is supposed to be an inferior quality of palma ro-a. 

 and its properties, therefore, should veiy closely resemble those of 

 the latter oil, excepting possibly its odor, unless it is highly diluted 

 with turpentine or mineral oil, as is frequently the ca-< . 



It can readily be seen that a judicious mixer could combine oils 

 possessing the properties described above so as to bewilder a chemist. 

 even though he were well versed in the chemistry of essential oils. 



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