M. TECHNOLOGY. 583 



at a temperature of 100. Rub the shafts of the feathers 

 with a piece of carbonate of ammonia, and place the feathers 

 a quarter of an Iiour in the soda solution, or, instead of it, in 

 a solution of twice the amount of carbonate of ammonia over 

 niarht. Rinse them Avith Avarm water on removal from this 

 bath, and lay them for five or six hours in a bath of nitrate 

 of iron, of 7 Baume ; remove, rinse with cold water, and 

 work them in a lukewarm bath of a decoction of two i^ounds 

 of logwood and two pounds of quercitron, heating it gradu- 

 ally, but not allowing it to boil, and let them remain in it 

 until they are perfectly black ; then remove, and rinse with 

 lukewarm water. Dissolve three ounces of potash in six 

 quarts of water, and stir half a pound of oil into the solu- 

 tion until it is. completely disseminated. Pass the feathers 

 singly through this bath, allow them to drain, without squeez- 

 ing them, and keeping them in motion until dry by fasten- 

 ing their shafts to a long cord stretched in a well-heated dry- 

 ing-room, a number of such cords being kept in motion by 

 connecting them with one at right angles, which can be pulled 

 slowly back and forth. The feathers thus recover their nat- 

 ural lustre. If but few are treated, they may be dried by 

 holding singly in the hand, and moving before a fire. Many 

 dyers dispense with the oil-bath by placing the feathers, aft- 

 er drying and rinsing, lengthwise, in layers, in a box, pow- 

 dering each layer with gypsum, removing them while moist, 

 and swinging them dry ; the last portions of gypsum being 

 removed with a soft brush. The shafts are then polished, 

 and the veins curled with suitably shaped hot irons. 2. 

 Another Blade: The feathers are cleaned as in the previous 

 case, and laid from one to two hours in a bath prepared by 

 boiling two pounds of prepared catechu, allowing it to settle, 

 carefully decanting the clear liquid, and bringing it to a tem- 

 perature of 122 before using. They are then placed in a 

 cold bath of acetate of iron, of-3 to 4 Baume, rinsed, and 

 dyed with logwood and quercitron as before, the subsequent 

 treatment being the same as in the first process given. 3. 

 JSroicn : The feathers are prepared as for black, and treated 

 in a similar manner in a decoction of two pounds of catechu, 

 and the dyeing then completed by Avorking them in a bath of 

 a quarter of a pound of bichromate of potash at a temperature 

 of 144 to 167. If not broAvn enough, they may be dipped 



