. NATURAL DYES OF THE PHILIPPINES 387' 



a brighter effect is produced, whereas tin mordant gives a more orange 

 colour. Potassium dichromate and ferrous sulphate employed in a similar 

 manner yield respectively olive and brown coloured shades. 



Silk is preferably dyed in an acid bath, and is sometimes previously 

 mordanted. 



Among other methods of obtaining the dye, Perkin and Eve- 

 rest * give the following : 



Perkin (Chem. Soc. Trans., 1904, 85,63) precipitates an alcoholic tur- 

 meric extract with lead acetate, washes the lead compound first with 

 alcohol, then with water, and decomposes it with dilute sulphuric acid. 

 From the mixture of lead sulphate and curcumin the latter is removed 

 with boiling alcohol and the extract evaporated and poured into ether, 

 which causes the separation of tarry impurities. The ethereal solution, 

 after evaporation to a small bulk, is treated with carbon disulphide and 

 allowed to stand, the crystals which separate from time to time being 

 removed. 0.56 per cent, of curcumin was thus obtained from turmeric. 



Cohen f gives several methods for preparing the dye, turmeric 

 yellow, from Curmima longa. 



Family MORACEAE 



Genus ARTOCARPUS 

 ARTOCARPUS INTEGRA (Thunb.) Merr. NangkI. 



A description of this species and its local names are given 

 in the section on food plants. 



The wood of nangka is used locally to a limited extent in 

 dyeing yellow shades, but the tree is much better known on 

 account of its fruit. 



Concerning this dye, Perkin and Everest J say : 



* * * The rasped wood is used by the natives of India and Java as 

 a yellow dye in conjunction with alum, for the robes of the Burmese 

 priests, also for dyeing silk and for general purposes. 



According .to these authors, the shades are very similar to 

 those given by old fustic; that is, olive yellow with chromium, 

 dull yellow with aluminum, and brighter yellow^ with tin mor- 

 dant. They say that its dyeing properties are due to morin, but 

 that unlike old fustic it contains no maclurin, and that a sample, 

 examined by Perkin and Cope, possessed only about one-third 

 of the dyeing power of old fustic, 



* Perkin, A. G., and Everest, A. E., The natural organic colouring 

 matters (1918), page 389. 



t Cohen, A. I., Indicators and test papers. 



t Perkin, A. G., and Everest, A. E., The natural organic colouring 

 matters (1918), page 219. 



