538 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Treated in this way, iron takes a steel-bine color, and zinc a 

 brown. Where sulphuric acid is substituted for the acetate 

 of lead, brass will be coated with a beautiful red, which is 

 followed by a green, and finally by a brown, with green and 

 red iridescent glitter. A number of applications of this very 

 useful discovery will doubtless suggest themselves. 



NEW MATERIAL FOR DYE-STUFFS. 



It is claimed that, according to a method patented by 

 Croissant and Breton niere, many kinds of refuse organic 

 matter, as sawdust, decayed wood, horn, bran, starch, moss, 

 etc., can be converted into valuable material for dyeing. 

 The process rests upon the dehyclrogenation of the sub- 

 stances by sulphur at high temperatures, and seems very 

 simple in practice. Thus bran, for example, is simply mixed 

 to a uniform paste, with the proper quantity of caustic soda 

 and flour of sulphur, in an iron vessel, which is then covered, 

 and heated in a furnace to 482-570. A portion of the sul- 

 phur is taken up by the organic matter, and much sulphu- 

 reted hydrogen is given off; and at the close of the opera- 

 tion a friable, hygroscopic mass remains, which is complete- 

 ly soluble in water, of a sap-green color, and exhibiting an 

 extraordinary affinity for organic fibres, so that they can be 

 dyed with it without a mordant. The dyes formed, even 

 from the same substance, may be varied in shade by alter- 

 ing the treatment ; and some materials require a much high- 

 er temperature than others for their transformation. 14 (7, 

 CCXL, 404. 



GOLD AND VIOLET BRONZE POWDER. 



The process for preparing these so-called powders, by 

 means of tin and fused acid tungstates, has been so im- 

 proved by Dr. Schnitzler as to be adapted to the prepara- 

 tion of them, in suitable furnaces, by the hundred-weight, 

 if the demand for them will justify it. He increased the 

 amount of tungstic acid to such an extent that, by pulver- 

 izing the mass obtained by the fusion of the ingredients at 

 a high temperature in a crucible, and heating it in a porce- 

 lain tube by a weak charcoal fire, it at most simply became 

 adherent by fusion. The reduction was then accomplished 

 in a few hours by common burning gas. By moderate tern- 



