THE INDIGENOUS DYES OF BENGAL. 159 



immersed in cool water for two or three days, and then boiled in a brass pot with 

 some alum. When the colour is sufficiently deep, the water is poured into a vessel — 

 more is poured into the vessel containing the wood and more colour extracted. The 

 cloth to be dyed is placed in a wooden dish and kept soaked with the dye for two or 

 three days. It is then dried in the sun. The process is repeated from three to six 

 times to the satisfaction of the Funghi." 



I did not obtain a satisfactory dyeing from the jackwood decoction alone. 



(i) Five gms. of silk was boiled for 30 minutes in a bath containing 5 gms. 



of jackwood chips and 1 gm. of alum. A moderately full yellow shade was 



obtained. 



Synthetic Dyes used for comparison with the Indigenous Dyes. 



Unfortunately no systematic determinations of the fastness to various agencies 

 of the dyeings with synthetic dyestuffs on silk appear to have been published. 

 Messrs. Cassella & Co. have undertaken such determinations for their dyes used in 

 cotton and wool dyeing, but apparently not for silk-dyes. The absence of such 

 information has rendered it necessary to examine a more extended series of synthetic 

 dyes than was necessary when studying cotton dyeing. In making a selection of 

 synthetic dyes, care was taken that those selected should be well-known dyes, should 

 include members of each of the more important groups, should include dyes generally 

 recognised as fast, and should give dyeings more or less similar in shade to the 

 dyeings with the indigenous dyes under examination. In making this selection the 

 following works and publications were consulted : — 



"Silk Dyeing, Printing and Finishing," by G. H. Hurst. 

 " Chemical Technology of Textile Fibres," by G. von Georgievics. 

 "Silk Dyeing," by Messrs. L. Cassella & Co. (Shade-card). 

 "Silk Dyeings fast to boiling off," by Messrs. L. Cassella & Co. (Shade-card). 

 "Aniline Colours on Silk" (shade-card, from Badische Anilin und Soda Fabrik). 

 The dyes selected were : — 

 Basic — 



Auramine II (Badische Anilin und Soda Fabrik). 

 Safranin, pur, (Dr. G. Griibler & Co.). 

 Magenta. 

 Neutral — 



Chrysophenine BB (Fr. Bayer & Co.). 



Sulphine A (Badische Anilin und Soda Fabrik) =Primuline. 

 Thiazine Red R (Badische Anilin und Soda Fabrik). 

 A cid — 



Orange No. 2. (Badische Anilin und Soda Fabrik). 

 Xaphthole Yellow S 8960 (Fr. Bayer & Co.). 

 Metanil Yellow E (Meister Lucius & Briining). 



