516 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



phate of soda, and enough water to dissolve the salt. The 

 coloring matter is added, and heated to a little above a luke- 

 warm temperature, when the fabric can be placed in the ket- 

 tle, and kept there until the desired shade is obtained; it is 

 then washed out in pure water. The sulphate of soda pre- 

 serves the color without further change. If a slightly red- 

 dish tint be desired, about one kilogramme of alum is to be 

 added to the bath. 5 C, xxxv., 278. 



NICKEL AND ANILINE. 



A patent has been taken out for the treatment of aniline 

 colors by means of* a salt of nickel. Green, purple, and a 

 very fine black can, it is said, be obtained in this way, and 

 used, under certain circumstances, to very great advantage. 

 25 C.Juhj 16,1871,222. 



ARTIFICIAL ALIZARINE. 



The artificial alizarine made in Germany, it is stated, is ex- 

 ceedingly pure. It is about twenty-five per cent, stronger 

 than mastic or madder of the same percentage of dry sub- 

 stance, while its color is much finer, purer, and more bril- 

 liant. It is furnished to the trade in the form of paste, con- 

 taining ten per cent, of dry, fine coloring matter, without any 

 other admixture. All the experiments made in printing and 

 dyeing with this preparation establish the fact that the arti- 

 ficial alizarine answers all the expectations that were raised 

 at the first announcement of its invention. For this reason 

 it is likely to displace madder from the materials used by the 

 dyer. 18 C, November 1, 1871, 703. 



DETECTING ADULTERATION OF SILK GOODS. 



An easy method of detecting adulterations of silk goods 

 with other fibres consists in immersing a sample of the arti- 

 cle in question in hydrochloric acid. This is an energetic 

 solvent of silk, and removes it in a very short time, leaving 

 the wool or cotton unaffected, at least for a considerable pe- 

 riod. Another experiment to the same end consists in drop- 

 ping a little of the acid on the sample, when, if pure silk, a 

 hole will be made ; if impure, the threads left will indicate 

 the nature and extent of the adulteration. 6 A, October 28, 

 1871,559. 



