142 TEXTILE FABRICS. [V. 



Black Dye for Felt Hats. — The composition of this dye, for 

 which a prize was awarded, is as follows. 1. The felt hat- 

 bodies are first cleaned, and galled by passing them through 

 the following solution, and washing : fustic, copperas, argal, 

 each 8ib, are boiled together in water for half an hour. 2. The 

 dye-bath consists of 55ft) campeachy wood, 1 Jib gum, 3ft) galls, 

 which are boiled together in water for 3 hours. To produce 

 the black color, 5ft) refined verdigris, 2ft) each of blue vitriol, 

 sugar, and quicklime, are added to the bath. (Bulletin de la 

 Soci^te d'Encouragement, August, 1846.) 



6. Color-'prmting . — The expansion of chemical science and 

 of calico-printing are simultaneous, and must necessarily be 

 so, for this beautiful art includes in it a larger share of the 

 principles and practice of chemistry than any other, or perhaps 

 than all other arts. Little of the experience of the calico- 

 printer is published, except by the issue of his beautifully 

 finished goods, and the cost of that experience is a sufficient 

 apology for his silence. 



Steam-blue for Printed Goods. — According to Petersen 

 (Polytech. Centralbl. 1847, 14) a topical blue for cotton, silk, 

 wool, &c. is obtained by printing a thickened mixture of 

 prussiate of potash with tartaric or sulphuric acid, and steam- 

 ing. The ferrocyanhydric acid, thus set free, penetrates the 

 fibre, depositing cyanide of iron, somewhat colored, which first 

 assumes a fine color by oxidation in a bath of chromate of 

 potash or chlorine, a blue protopercyanide being formed.. 



The lively tone of French blue is due to the use of tin-salt 

 together with the others, or to ferrocyanide of tin, which is 

 obtained by adding tin-salt to prussiate of potash. 



Prussian-blue for Calicoes. — A solution of pertartrate and 

 persulphate of iron is treated with ammonia in excess, and 

 then with yellow prussiate of potash. Cotton is not imme- 

 diately colored when dipped into this solution, but by subse- 

 quent exposure to the air, it assumes a violet-blue, which passes 

 into a beautiful deep-blue when passed through a bath of tin- 

 salt. (Dingl. Journ. xcix. 399.) 



White Discharge on Indigo. — This is usually effected by 



