— 106 — 



better than that of the one received before, as it dissolved in every 

 proportion in 90 per cent, alcohol; when highly diluted (1:10) a faint 

 opalescence occurred. With 10 vol. 80 per cent, alcohol it did not form 

 a clear solution. 



Whether these differences between the two oils must be attributed 

 to various methods of distillation, or to different stages of develop- 

 ment of the plants due to the time of the year, we are unable to say. 



Along with the oil just discussed we also received another sample 

 of the pilea oil already described in detail in our last Report 1 ). The 

 oil now received showed a greenish tinge, and had a considerably 

 higher rotation, «d~|- 58°20 / ; for the rest it agreed with the previous 

 oil; di 5 o 0,8520; n D20° 1*46902; acid no. o; ester no. 7,7; ester no. 

 after acetylation 34,4; soluble in 3,8 and more vol. 90 per cent, 

 alcohol. 



From the buds of the Black Currant (Ribes nigrum L.), which 

 had been sent to us from Russia, we obtained in a yield of 0,75 °/ 

 an essential oil of the following constants: d^o 0,8741; <*j> -{-2° 30'; 

 n D20° 1*48585; acid no. o; ester no. 5,6; soluble in 6,5 and more vol. 

 90 per cent, alcohol with slight cloudiness, which disappears on greater 

 dilution (1:10). The oil had a pale greenish colour and, judging 

 from the odour, appeared to contain among others cymene. As we 

 only had a few grams of oil at our disposal, we must content ourselves 

 with the enumeration of the foregoing data. 



Ayapana Oil. The oil of Eupatorium triplinerve Vahl {E. Ayapa?ia 

 Vent), a composite indigenous to equatorial Africa, which in other 

 tropical districts is often growing wild, but in the East Indies is cultiv- 

 ated as a tea-plant, was sent to us from Mayotte, one of the Comoro 

 islands, in the Straits of Mozambique, under the name of "essence 

 d'ayapana". 



The oil has a pale-green colour and a peculiar odour; d^o 0,9808; 

 «d-(- 3 io ; ; ester no. 8,0; ester no. after acetylation 23,4. It forms 

 a clear solution with i x / 2 times its vol. 90 per cent, alcohol, but is 

 practically insoluble in 80 per cent, alcohol. On fractional distillation 

 at 3,5 mm. pressure it was found that, apart from a small quantity 

 first runnings with a terpene-like odour, and an equally unimportant 

 residue, the oil boiled almost uniformly. We obtained three fractions 

 with the following properties: 



I. 



40 to 104 



5,6 % 



diso 0,9680 



2. 



I04° 



51,8% 



d 15 o 0,9825 



3- 



104 to 105 



28,0% 



d 15 o 0,9848 





residue: 



15,9% 





'35' 

 ' 5' 



*) Report October 1906, 83. 



