L. TECHNOLOGY. 447 



desirable color can be directed over the cloth spread out on 

 a table. If two colors are desired, it is only necessary to 

 sprinkle the cloth first with one and then with the other. 

 After the dye is sprinkled upon the surface of the cloths or 

 fabrics, they should be folded face to face, and either passed 

 between rollers or pressed by blocks, so as to drive in and 

 further distribute the color on the cloths. 5. (7, 1870, xl., 314, 

 and 8.4,1870,225. 



NEW BLEACHING PROCESS. 



In a new bleaching process, the wool or silk, having been 

 first cleaned in the usual way, is to be steeped for about an 

 hour in a solution of equal parts, by weight, of oxalic acid 

 and chloride of sodium in clear cold water, after which it is 

 removed from the bath and allowed to drain, and then wash- 

 ed in the ordinary manner. The same bath may be used re- 

 peatedly by adding at each fresh charge of wool or silk a lit- 

 tle more oxalic acid and chloride of sodium. The materials, 

 while in the bath, should be stirred, and in the case of woven 

 fabrics they should be passed through rollers. Should it be 

 required to impart a blue color to the materials, the color 

 employed should be first dissolved, filtered, and strained, and 

 then introduced into the mordant bath, in proportion varying 

 with the shade required. 8 C\ March 17, 108 ; 14 C, CXIX., 

 174. 



elsner's zinc green. 



According to a recent formula, Eisner's zinc green may be 

 prepared by stirring up five parts, by weight, of the oxide of 

 zinc and one part of dry sulphate of cobalt with a sufficient 

 quantity of water, drying the paste and exposing it to a red 

 heat, which, on cooling, is found to be a dark green powder. 

 If ten parts of oxide of zinc and one part of sulphate of cobalt 

 be used, the product is a grass green color, and with twenty 

 parts of oxide of zinc the color is light grass green. The lat- 

 ter is most esteemed, because it is capable, under certain cir- 

 cumstances, of replacing the injurious Schweinfurt green, and 

 because it fastens well upon lime, plastering, or whitewash, 

 which is not the case with a green prepared from a mixture 

 of Berlin blue and chrome yellow. 8 (7, June 23, 199. 



