530 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



tides to be coated are placed. The sulphate of iron nmst be 

 entirely free from copper. At the end of one or two minutes 

 the objects must be withdrawn, and the black coating of the 

 iron already deposited removed by brushing under water. 

 The articles are then to be again placed in the hot bath, and, 

 after they have acquired a second black coating, held over a 

 vessel filled with burning charcoal until the ammoniacal va- 

 pors caused by the heat cease to be disengaged. This oper- 

 ation is to be repeated three or four times, the articles being 

 washed off before each immersion. The black layer fixed by 

 heat is said to adhere firmly to the zinc, and to assume a per- 

 manent polish under a brush. 1 j5, July 28, 1872, 296. 



ANTIMONY BLUE. 



A new blue color has lately been made from antimony, 

 which is pronounced very beautiful and durable, but not ap- 

 plicable to plastered surfaces. The metallic antimony is dis- 

 solved in aqua regia, filtered through granulated glass, and 

 mixed with a weak solution of prussiate of potash until pre- 

 cipitation ceases. It can scarcely be distinguished from ul- 

 tramarine, and is said to be very effective in coloring artifi- 

 cial flowers. Mixed with chrome yellow it gives a green 

 color, almost as brilliant as the dangerous arsenious com- 

 pounds, which thereby may be superseded. 15 C, vn., 112. 



NEW BLUE. 



A new blue has lately been obtained by a special treat- 

 ment of phenol and stannate of soda. When cotton cloth is 

 placed in this solution it first becomes a beautiful orange 

 color. It is then to be washed, first in an alkaline solution, 

 which turns it green, and afterwards with water, which leaves 

 it a celestial blue. The blue dye thus produced is almost 

 unaffected by chlorine and hypochlorites, and does not fade 

 by exposure to sunlight. 3 A, July, 1872, 33. 



DYEING WOOL AND SILK SCAKLET. 



A mixture of dinitro-naphthal and fuchsine has been recom- 

 mended for dyeing wool and silk scarlet. An aqueous solu- 

 tion of dinitro-naphthal is heated to nearly its boiling point, 

 and about two per cent, of fuchsine, in solution, added. It is 

 absolutely necessary to mix the two ingredients at a high 



