L. TECHNOLOGY. 449 



smell, which can, however, be removed by placing the straw 

 in water in which a little sulphate of soda has been dissolved, 

 and then rinsing it off with fresh water. 15 (7, 1870, 106. 



CHINESE GOLD LACKER. 



A German experimenter has lately discovered the method 

 of producing the celebrated Chinese gold lacker, his imita- 

 tions being entirely successful. His method of preparing this 

 substance is to melt two parts of copal and one of shellac, so 

 as to form a perfectly fluid mixture, and then add two parts 

 of hot boiled oil. The vessel is then to be removed from the 

 fire, and ten parts of oil of turpentine gradually added. To 

 improve the color, an addition is made of a solution in tur- 

 pentine of gum gutta for yellow, and dragons' blood for red. 

 These are to be mixed in sufficient quantity to give the de- 

 sired shade. The Chinese apparently use tin foil to form a 

 ground, upon which the lacker varnish is laid. 3 A, June 17, 

 436. 



GIVING A BLACK COLOR TO HORN". 



A process recently announced for imparting a black color 

 to horn, without the aid of heat, consists in taking the arti- 

 cles, finished and ready for polish, and immersing them in a 

 lye of caustic potash or soda until the outer surface of the 

 horn is somewhat dissolved, as shown by a greasy feel. With 

 care, fine-tooth combs can be treated in this way without any 

 injury. They are then washed off and dipped in aniline 

 black, slowly dried, and then again washed off. By trans- 

 mitted light the horn is of a dark brown color, but by reflect- 

 ed light it is of a deep black. 5 (7, xvil, 136. 



DYEING WOOL ANILINE BLUE. 



The following method is recommended for dyeing aniline 

 blue upon wool. The quantities given are sufficient for twen- 

 ty yards. Three quarters of a pound of Marseilles soap are 

 dissolved by boiling, and, when cold and sufficiently diluted 

 with soft water, the goods are soaked in the liquid and well 

 wrung. They are then placed in a bath of hot water acidu- 

 lated with sulphuric acid, to which the coloring solution is 

 added in accordance with the shade required. This solution 

 consists of an ounce and a half of aniline blue in a pound and 



