CHEMICAL SCIENCE. 215 



merits, to replace every other substance in use for the same purpose up to 

 this day, and is more brilliant than any dye hitherto known. The discoverer 

 has registered his patent for its use under the name of "Algerian Carnpeachy 

 Wood." 



DECOLORATION OF INDIGO BY SESQUI-OXIDE OF IRON. 



According to Kuhlman, when a solution of blue indigo is acted upon, at 

 the temperature of one hundred and fifty degrees (C), by hydrated oxide of 

 iron, its color is almost immediately completely destroyed. The same thing 

 occurs with a number of other coloring matters. In noticing this fact, 

 Barreswil suggests that persulphate of iron may perhaps be applied in 

 calico-printing as a discharge for indigo, and also in bleaching blue rags for 

 paper-making. Repertoire de Chimie Appliqiie'e, October, 1859. 



ON THE RENDERING OF FABRICS INCOMBUSTIBLE. 



The Repertoire de Chimie publishes a paper from the well-known chemists 

 MM. Doc'bereiner and (Eisner, on the various methods for rendering stuffs 

 incombustible, or at least less inflammable than they naturally are. The 

 substances employed for this purpose are borax, alum, soluble glass, and 

 phosphate of ammonia. For wool and common stuffs any one of these 

 salts will do; but fine and light tissues, which are just the most liable to 

 catching fire, cannot be treated in the same way. Borax renders fine textile 

 fabrics stiff; it causes dust, and will swell out under the smoothing-iron; so 

 does alum, besides weakening the fibres of the stuff, and making it tear easily. 

 Soluble glass both stiffens and weakens the stuff, depriving it both of elas- 

 ticity and tenacity. Phosphate of ammonia alone has none of these incon- 

 veniences. It may be mixed with a certain quantity of sal-ammoniac, and 

 then introduced into the starch prepared for stiffening the linen; or else it 

 may be dissolved in twenty parts of water, in weight, to one of phosphate, 

 and the stuffs steeped in the solution, then allowed to dry, and ironed as 

 usual. Phosphate of ammonia is cheap enough to allow of its introduction 

 into common use, so that it may be employed at each wash. 



STEINBUHL-YELLOW, A NEW KIND OF CHROME- YELLOW. 



Under the above name a yellow color has been for some time in commerce, 

 which is quite certain to find much favor, all hough its price is far higher 

 than that of the ordinary chrome-yellow. It is of a splendid yellow, and 

 differs essentially in its tint from the best samples of chrome-yellow. Irs 

 components are chromic acid, lime, and potash; and when stirred for a short 

 time with cold water, it parts with chromatc of lime. 



The poisonous qualities of chromic acid and its soluble salts, and the cir- 

 cumstance that the color parts with perceptible although not large quantities 

 of chromic acid to cold water, render the Steinbiihl-yellow an extremely 

 dangerous coloring-matter; and its employment in confectionery, and the 

 like uses, must not be thought of. 



PROCESS FOR GIVING OBJECTS A PEARLY LUSTRE. 



To produce the iridescence of the mother-of-pearl on stone, glass, metal, 

 resin, paper, silk, leather, etc., lieinsch adopts the following process: Two 



