578 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



and, as the result of numerous inquiries, he finds that it has 

 about the same affinity for mordants as alizarine, and that 

 the colors it produces are analogous to some extent, as it 

 produces red with alumina, purple and black with iron mor- 

 dants. It is, however, in many respects superior to alizarine, 

 as the reds are much purer and less blue than those of 

 alizarine, while the purples are bluer and tlie blacks more 

 intense. The fastness of the colors, against soap and light, 

 is equal to that of alizarine. When used to dye turkey-red 

 it produces very brilliant colors of a scarlet shade, which 

 are of remarkable permanence. Specimens presented in con- 

 nection with the communication of Mr. Perkin show a decided 

 superiority over alizarine in the purity and brightness of 

 the proper color. 21 A, Mai/, IS'^^? 425. 



USES OF PUEPUKINE. 



Purpurine can be employed for dyeing cotton, avooI, or 

 silk of a black, red, rose, or lilac color. Cotton is printed 

 with the usual madder mordant, colored, and soaped at 122^ 

 to 144 to restore the whites and clear the colors. Passing 

 through bran improves the w^hites. Wool is mordanted in 

 alum and tartar, or bichloride of tin and tartar, and dyed by 

 boiling half an hour in a purpurine-bath. A little tannin 

 may be added with advantage to the mordant. For printing- 

 wool, about 300 grains of purpurine J^nd 60 grains of carbon- 

 ate of soda are dissolved in hot Avater, thickened with starch, 

 and increased, to about one quart, then printed, and steamed. 

 For crimson, alum and tartar are nsed as mordants. Silk 

 takes colors beautifully, especially reds, by mordanting with 

 acetate of alumina and chalk, drying, gumming slightly with 

 tragacanth solution (100 to 200), printing with a solution of 

 480 grains of purpurine and 180 grains of crystallized carbon- 

 ate of soda in water, filtered, and thickened with 3000 grains 

 of roasted starch, then steamed and soaped at 144. 13 C, 

 3Iarch 15, 1873, 403. 



DYEING SILK. 



The practice of boiling with soap in the process of scour- 

 ing silk has recently been abandoned ; and it is, instead, sim- 

 ply plunged into a boiling soap-bath containing one-quarter 

 pound of Marseilles soap to each pound of silk, until it is en- 



