1835.] Calico-Printing. 169 



depending upon the shade of colour wanted. The cloth is 

 entered into the boiler while the water is cold. It is made 

 to boil in an hour, and the boiling is continued for two 

 hours. During the whole of this time the cloth is passed 

 through the dyeing liquor by means of the winch. 



For every 25 lbs. of cloth dyed, one gallon of bullock's 

 blood is added. This is the quantity of cloth dyed at once 

 in a boiler. The addition of the blood is indispensable for 

 obtaining a fine red colour. Many attempts have been 

 made to leave it out, but they have been unsuccessful. I 

 suspect that the colouring matter of blood is fixed upon the 

 cloth. Its fine scarlet tint will doubtless improve the colour 

 of madder- red. 



(14.) Madder contains two colouring matters, a brown and 

 a red. Both are fixed on the cloth by the dyeing process, 

 giving the cloth a brownish red, and rather disagreeable 

 colour. The brown colour is not nearly so fixed as the red. 

 The object of the next process, called the clearing process, is 

 to get rid of the brown colouring matter. The cloth is 

 boiled for twelve or fourteen hours in a mixture of 5 lbs. 

 soda, 8 lbs. soap, and from 16 to 18 gallons of the residual 

 liquid of No. 9, with a sufficient quantity of water. By this 

 boiling the brown colouring matter is mostly removed, and 

 the cloth begins to assume the fine tint which characterizes 

 Turkey-red dyed cloth. It is still further improved by the 

 next process. 



(15.) Five or six pounds of soap, and from sixteen to 

 eighteen ounces of protochloride of tin, in crystals, are dis- 

 solved in water in a globular boiler into which the cloth is 

 put. The boiler is then covered with a lid, which fits close, 

 and the boiling is conducted under the pressure of two 

 atmospheres, or at the temperature of 250|°. The boiler is 

 furnished with a safety valve and a small conical pipe, the 

 extremity of which has an opening of about x |ths of an inch 

 in diameter, from which there issues a constant stream of 

 steam during the operation. The salt of tin is found mate- 

 rially to improve the colour. Probably the oxide of tin 

 combines with the oleaginous acid of the soap (fixed in the 

 cloth.) This insoluble soap doubtless unites with the red 

 colouring matter of the madder, and alters the shade. 



(16.) After all these processes, the cloth is spread out on 



