Examination of Essential Oils. 



21 



the line Cd 23. The absorption disappears as this band widens out by 

 reason of further dilution. 



Since oil of cassia consists mostly of cinnamic aldehyde, which has 

 the composition C 6 H 5 .C 2 H 2 .COH, the aromatic nucleus is here again 

 accountable for the absorption. 



Oil of Thyme (Dr. Gladstone). — Nearly the whole of the specimen 

 distilled between the temperature of 220° and 240° C. A. brown 

 resinous residue remained in the retort. Portions of the oil were 

 examined in solutions containing T ^ u , Toki and 20000 - ( See 



Diagram 20.) 



Diagram 20. 



Oil of thyme. Portion boiling 220 — 240°. Absorption clue to thymol. 



A characteristic absorption may be traced to the presence of thymol, 

 a substance already examined with other benzene derivatives. (See 

 Part II of this research.) 



Car vol (Dr. Gladstone). Separated from oil of carraway by distil- 

 lation. — The liquid distilled almost entirely between 215° and 220°. 

 The portion boiling between these temperatures was examined after 

 dilution 1,000, 10,000, 100,000, 120,000, 150,000, 200,000, 250,000, and 

 300,000 times its volume with alcohol. (See Diagram 21.) 



The absorptive power of this body is remarkable, and is undoubtedly 



