602 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



is laid on a plate of coj^per, or exposed to hydrogen or vapor 

 of phosphorus, the unchloridized parts blacken, and a per- 

 fect copy of the design is obtained, which may afterward be 

 fixed in the regular way. 21 A, Mmj^ 1878, 538. 



SULPHATES OF SODA AND POTASSA IN BLEACHING ANIMAL 



FABRICS. 



A patent has lately been obtained by Samal & Beronson, 

 for the use of feeble solutions of the sulphates of soda and 

 of potassa, in bleaching animal textile fabrics ; their special 

 object being to remove the gum in prej^aring silk and in 

 scouring wool. For the first-mentioned object the bath must 

 be boiling ; while for the second, the temperature of the al- 

 kaline sulphuret should not exceed 120. Where it is espe- 

 cially difticult to remove the gum and prepare the silk, the 

 proto-sulphuret may be employed. The aluminates of soda 

 and of potash have also been used for the same j^urpose. 18 

 ^,1873,402. 



WHITENING WOOL. 



The sulphurizing of wool can, to a certain extent, be avoid- 

 ed by placing it, after scouring, in a bluing bath at 122, 

 composed (for fifty pounds of wool) of alum, 2 pounds ; tartar, 

 9 ounces ; sulphuric acid, 1 pound ; starch, 9 ounces ; sulphate 

 of indigo, 3 ounces; archil, 1^ ounces, and working at that 

 temperature for three quarters of an hour. The white thus 

 obtained, though generally satisfactory, can be much im- 

 proved by squeezing out the wool, without Avashing it, and 

 dipping it in a lukewarm solution of one pound of chloride of 

 barium. The sulphate of baryta, or permanent Avhite, de- 

 posited in the fibres, adds to the weight as well as the white- 

 ness of the wool. 26(7,1873,108. 



BLEACHING DISCOLOEED FLANNEL. 



It was found by Professor Artus that flannel which had 

 become yellow by lying for some time, when treated with a 

 solution of one and a half pounds of Marseilles soap in fifty 

 pounds of soft water, with the addition of one eighth of an 

 ounce of ammonia, and subsequently rinsed, was much im- 

 proved in appearance. The bleaching was more quickly ac- 

 complished by soaking the articles for an hour in a dilute 



