Examination of Essential Oils. 3. 



The general similarity of the curves is a noticeable feature as well as 

 the intensity of the absorption of the extremely refrangible rays. 



DlAGKAMS 1 — 4. 



Showing the rays transmitted after dilution with various proportions of alcohoL 

 Isomeric Terpenes. 



ca 



IB W. IB £6 



VOLS 

 



1 1 III 1 



100 





1000 



AUSTRALENE \ 



5000 







 IOO 







200 

 400 



1 000 



TEREBENE \^ 

















100 

 500 





1000 



terebentheneX 



5000 







 100 



— — 



500 



HESPERIDENE 



5000 





The ordinates represent the proportions of alcoholic solution containing one volume 

 of the terpene. Thickness of the layer of liquid = 15 milhms. 



. It wil1 be seen that australene and terebenthene show slightly 

 different curves, the latter being rather less diactinic when diluted 100 

 and 500 times. Another difference between these bodies is that one 

 rotates the polarised ray to the right and the other turns it to the left. 

 The following substances were from Dr. Gladstone's collection — 

 Oajjmtene dihydr ate. -The main portion of this liquid boiled at 

 L76 C, and none distilled over below the temperature of 170°. Solu- 

 tions containing ^ t _l_ were examined. An absorption, 



T< 9 



