M. TECH^^OLOGY. 493 



as fast. A sample of wool dyed with it was scarcely affect- 

 ed by a week's exposure to the sun. The discoverer is a 

 New York chemist. Manvf.Remeic^N. Y. 



GEORGINE, A NEAV YELLOW DYE. 



A new yellow dye has been named Georgine, by Singer, 

 of Tournay. It is said to be easily fixed upon all kinds of 

 fibres, needing no mordant with silk and wool, but with 

 cotton requiring previous treatment with alum, or passage 

 through a cold or lukewarm sumac bath. For printing upon 

 wool, cotton, or half-wool, it is thickened with gum water. It 

 may also be employed to bring out the colors of turmeric, 

 fustic, and picric acid, and afifords mixed colors of remark- 

 able purity, with other dye-stufi^s. 26 (7, XL, 14. 



BAEYTA-GEEEN. 



Bottger recommends the following mode for the prepara- 

 tion of baryta-green : Add gradually two parts of finely 

 sifted peroxide of manganese to a mixture of two parts of 

 caustic potash and one part of chlorate of potash in a state 

 of fusion, and finally heat the mass to a low red heat. Al- 

 low it to cool, powder it, pour cold water over it, filter, and 

 add to the green filtrate, in the cold, a solution of nitrate of 

 baryta. Wash well with water the beautiful violet neutral 

 manganate of baryta that separates, and when dry mix with 

 it from one half to one part of hydrate of baryta, and heat 

 the mixture at a low red heat, in a rather shallow brass or 

 copper vessel, with continued stirring, until the contents, 

 upon cooling, manifest a pure green color. Finally, pulver- 

 ize it thoroughly, and treat repeatedly with cold water, in 

 order to remove any hydrate of baryta present. 20 A^ 

 March 27, 338. 



DYEING COTTON PUEE BLUE. 



The following is suggested by BOttger for dyeing cotton 

 a pure blue. Heat a mixture of 137 grains of Paris blue, 

 137 grains of tartaric acid, one half a fluid ounce of ammonia 

 water, and two and a half fluid ounces of water, and filter, 

 after cooling. Add to the deep blue filtrate a solution of 

 caustic soda until it is decolorized, and after some time as- 

 sumes a light yellow tint. Impregnate the cotton with this 



