256 TROPICAL AGRICULTURE 



the oil the petals are carefully distilled. It has been found 

 from experience with this material that 300 to 350 pounds of 

 flowers will yield I pound of oil. Ylang-ylang oil is easily 

 damaged to a serious extent by exposure to light and ahr. 

 It is also extremely volatile and will readily escape except 

 from very tightly-stoppered bottles. Manila exports about 

 4,500 pounds of ylang-ylang oil annually. The perfume which 

 is sold under the name ylang-ylang commonly contains cologne 

 water, essence of rose, tincture of vanilla, tincture of tolu, 

 and oil of neroli, to which a minute quantity of ylang-ylang 

 oil is added. An excellent quality of this oil is produced in 

 Reunion, where the yield is reported as being frequently as 

 high as 2 per cent, of the flower petals by weight. Good 

 samples of ylang-ylang oil have also been received from the 

 Comoro Islands, while the oil received from Mauritius is of 

 inferior aroma. Madagascar has also given considerable atten- 

 tion to the production of this oil. 



FRANKINCENSE 



The term frankincense is applied to various resins which 

 yield a strong fragrance in burning. Olibanum, a resin exud- 

 ing from Boswellia serrata and other species of this tree in 

 India and Africa, is also known as frankincense. Olibanum 

 occurs as clear yellow drops of resin on the bark of these 

 trees and is used for burning in religious celebrations and for 

 scenting pastilles and in fumigating powders. The resins in 

 certain species of fir and croton have also been used for the 

 same purpose under the name frankincense. 



TONKA BEAN 



The tonka bean comes from a large leguminous tree (Dip- 

 teryx odorata) which bears handsome violet-colored flowers 

 and long fibrous pods containing the black bean. The tree 



