208 ANNUAL OF SCIENTIFIC DISCOVERY. 



hol is highly fluorescent, which reaction affords, according to 

 Hoffman, a method of distinguishing it from aniline red. In 

 depth of color it is said to be equal to aniline, while it is superior 

 to that dye in permanency, but it loses lustre on dark tints, and 

 hence its use is limited to light shades. Druggists 1 Circular. 



Soluble Garnet. The "Engineer" states that the new dye 

 known as soluble garnet seems to be coming more largely into use 

 on the continent, and as the colors produced with it are exceed- 

 ingly brilliant, similar to those obtained with archil, but much 

 more stable when exposed to light and air, the garnet dye is likely 

 to become a great i'avorite. The dye was first prepared by 

 Casthelaz of Paris, and is the ammonium salt of isopurpuric acid, 

 which is formed by the action of a metallic cyanide upon picric 

 acid. It is not prepared from the pure crystallized, but from the 

 inferior kind of picric acid, and is probably designed to replace 

 the archil in many cases, in imparting to wool all shades from 

 garnet to chestnut-brown. It may be readily combined with 

 other pigments, so that a number of different colors may be 

 obtained. According to Casthelaz, the dyeing of silk or wool is 

 affected by the addition of an organic acid to the bath, for instance, 

 acetic or tartaric acid, mineral acids being excluded. The dye- 

 bath for silk should be cold or tepid in the beginning. Different 

 shades in red or brown are thus obtained that are dependent 

 upon the concentration of the bath, the nature of the mordant, 

 and the time of the operation. Nature, Aug. 4, 1870. 



Bleaching of Fixed Fatty Oils. M. Dieterich. Into a wooden 

 tub, provided with a properly constructed tap at the bottom, are 

 poured 30 litres of water, wherein 1 kilo, of permanganate of potas- 

 sium is dissolved. To this mixture is added 50 litres of the oil to 

 be bleached, and the fluids well stirred up for about 2 days ; at 

 the end of that time 20 litres of boiling water and 5 kilos, of 

 commercial chlorhydric acid are added ; the liquid is again well 

 stirred up, and, after 2 more days, the acid liquor is run off by 

 means of the tap, and, having been removed, the oil is repeatedly 

 washed with boiling water, until all the acid is removed from it. 

 Moniteur Scientijique. 



Oxide of Zinc as a Mordant. Biot and Thirault have patented 

 a method for the use of oxide of zinc as a mordant for the dyeing 

 of cotton with aniline blue, and for fixing iodine green on wool. 

 G. Merz, of Chemnitz, uses oxide of tin as a mordant for fixing 

 iodine green on cotton and wool. Deutsche Industrie Zeitung. 



New Mordant. - - For fixing colors in dyeing and printing, M. 

 Kipping, of Manchester, makes use of the property of gelatine 

 and gum of becoming insoluble in water after the addition of 

 solution of a chromate. The coloring matters are mixed with 

 gelatine or gum and some chromate, as the bichromate of potas- 

 sium. Commercial gelatine is dissolved in water and one-sixth 

 its weight of bichromate is added to the solution, the operation 

 being performed in a rather dark room ; the coloring matter is 

 next added to the mixture. The strength of the solution of 

 gelatine depends 011 the consistency of the color to be employed. 



