M. TECHNOLOGY. 529 



turning for half an hour, and is then wound out, and the 

 bath is again heated to 158, and the yarn worked in it 

 again for the same length of time, and removed, and well 

 cooled and allowed to lie overnight. It is to be rinsed 

 shortly before dyeing, which is done according to sample, 

 in a clear bath, by means of iodine and picrine, wooden ves- 

 sels being employed throughout the whole oj^eration. 26 C, 

 XVI. 1874, 155. 



IMPROVED CHROME GREEN. 



Practical chemists have, for a long time, had their atten- 

 tion directed to the problem of manufacturing permanent 

 greens, otherwise than as combinations of arsenic; and it is 

 now announced that a very fine and intense chrome green 

 can be prepared by heating a mixture of equal parts of sul- 

 phur and bichromate of potash to redness in a crucible. 

 The product is then to be leached with hot water, which 

 dissolves the sulphide and sulphate of potassium produced, 

 and leaves the oxide of chromium as a fine powder of an 

 intense green color. 18 A, October 16, 1874, 118. 



BEHAVIOR OF ANILINE COLORS TOWARD INFUSORIAL EARTH. 



According to Bottger, after shaking an alcoholic solution 

 of any aniline color with a sufficient quantity of infusorial 

 earth, and then adding some water to the mixture, and bring- 

 ing the whole upon a paper filter, the filtrate will be found 

 to be perfectly colorless, the coloring matter being retained 

 by the earth. 15 C, XVI., 256. 



NEW DYES OF CROISSANT & BRETONNIERE. 



A very important advance in the art of dyeing has been 

 made by the discoveries of Messrs. Croissant & Bretonniere. 

 These consist in the treatment of certain organic substances, 

 such as w T ood, sawdust, lichens, moss, gluten, starch, sugar, 

 tannin, gelatin, blood, horn, soot, sundry acids, and alkaline 

 solids, resins, etc., by means of certain sulphides, at a more 

 or less elevated temperature. The process of manufacture 

 is very simple and inexpensive, according to Messrs. Wirth 

 & Co., at Frankfort-on-the-Main, not exceeding $10 per hun- 

 dred pounds ; the profits being much greater than those from 

 the manufacture of aniline colors. The new dyes comprise 



Z 



