L. TECHNOLOGY. 519 



it is argued that, in the increased demand, there will be remu- 

 nerative employment for several new establishments. 24(7. 



SUBSTITUTE FOR BICHROMATE OF POTASH. 



The recent increase in price of bichromate of potash con- 

 tinues to exercise the minds of manufacturers, especially in 

 Germany, in view of the fact that it is obtained from chrome 

 irons, which occur abundantly in various parts of the world, 

 especially in Sweden ; and this increase of price is considered 

 to be the result of a combination on the part of the manufac- 

 turers, and not a real necessity. 



The use of other substances is therefore urged, by which 

 the demand for the bichromate of potash may be reduced, 

 and its manufacturers thereby brought to terms. A writer 

 in one of the German dyeing journals calls attention to the 

 fact that for many purposes, such as for coloring black, Glau- 

 ber's salt and sulphuric acid can be substituted to great ad- 

 vantage ; and he gives the following recipe for dyeing one 

 hundred pounds of loose wool, namely, six pounds of Glau- 

 ber's salt, two pounds of sulphuric acid, and two pounds of 

 blue vitriol, which are to be boiled together for an hour, and 

 colored with forty to fifty pounds of logwood and one pound 

 of blue vitriol, and finally colored black by means of a little 

 green vitriol. The black thus obtained is pronounced to be 

 beautiful, cheap, and easily spun, remaining loose and soft. 

 26 C, xvi., 125. 



DYEING WITH IODINE GREEN. 



According to a German chemist, the difficulty which has 

 been experienced in dyeing with the new color, iodine green, 

 results from the fact that the operation has been performed 

 in metallic vessels, such as tin, copper, or brass, when, in re- 

 ality, nothing but wood should have been employed. He 

 communicates the following formula for using this color, 

 which he thinks will be always found satisfactory : One part 

 of purified soda water-glass (silicate of soda) is to be com- 

 bined with six parts of water, and the wool well washed, and 

 allowed to lie at a lukewarm temperature for three hours in 

 the solution, due regard being had to the volume of the liquid. 

 The wool is then to be wrung out and dried without rinsing. 

 Liquid iodine green is then to be poured into the water, 



