44G ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



madder, and about twelve and a half drachms of proto-chlo- 

 ride of tin, to be dissolved in a vessel containing about 500 

 quarts of cold water and a pound of cold slacked lime. 8 A, 

 March 1,68. 



BRONZING COPPER ARTICLES. 



A method indicated for bronzing copper articles consists 

 in first making the surface thoroughly clean and bright, and 

 then covering it with a thick coating of rouge and water, 

 and after drying it is to be placed for a short time in a hol- 

 low fire (as a chamber of bricks red hot) until the rouge has 

 turned to the desired color. It is then to be placed in a suit- 

 able stand and polished with a soft brush and rouge powder, 

 and afterward with soft leather. 8 A, 1870, December, 224. 



IMPARTING A BLACK COLOR TO COPPER. 



A beautiful black color may be imparted to copper by first 

 cleaning it with sand and sulphuric acid, and then applying 

 a liquid prepared by dissolving two parts of ordinary white 

 arsenic in a mixture of four parts of hydrochloric acid, one of 

 sulphuric acid, and twenty-four of water. 5 C, 45, 364. 



SPECKLED FABRICS. 



The manufacture of fabrics in which minute specks of one 

 color are seen on a dark ground is becoming very common, 

 this result being generally produced by the introduction of 

 a silken thread. The same effect, however, is now accom- 

 plished, and in some cases much more readily, without weav- 

 ing in the dots, by a different arrangement. The speckles 

 themselves are applied by the help of a sprinkling apparatus, 

 which divides the oil color very finely and sprinkles it over 

 the cloth. The apparatus consists of a tin box, closed every 

 where excepting on the front side. The oil color is placed 

 upon the bottom of the box, and into this is immersed a 

 small rotating, cylindrical brush, which lies parallel to the 

 open side of the box, and can be turned by means of a crank. 

 The bristles of the brush, in rotating, after being saturated 

 with the oil color, strike against a small bar, and throw out 

 the oil-color dust in very fine drops. On the back side of 

 the box is a handle, by which it is held in the left hand, while 

 the right turns the crank. In this way the dust-rain of any 



