5-10 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



treated by means of chlorine in a vat, and the bleaching 

 finished by the use of permanganate of potash. The material 

 is now a soft, pulpy, and highly fibrous substance, which is 

 next subjected to the action of a hydro-extractor, a kind of 

 wringer, which leaves it in the shape of a damp, fleecy mass. 

 The liquid with which the fibre has been treated is then 

 pumped into a vat, and subjected to the action of carbonic 

 acid gas, which solidifies to some extent the resinous particles. 

 It is next placed in a copper boiler, and heated exactly to the 

 boiling-point. This produces a complete coagulation of the 

 resin, which falls to the bottom in large flakes. No use has 

 been, so far, found for this resin, but it is expected that before 

 long it may become of commercial value. There are many 

 other details in the manipulation of the fibre, for which refer- 

 ence must be made to the technical journals. 18-4, June 28, 

 1872,372. 



A NEW INDUSTRY. 



Under this title, a French contemporary brings to our no- 

 tice the account of a process for manufacturing mirrors that 

 has infinite advantages of every kind over those constructed 

 of mercurial amalgam. Many of our readers are well aware 

 of the difficulties attendant upon the construction of a really 

 good and perfect mirror, such as is in ordinary use. The 

 necessity of having glass of a certain quality and perfect uni- 

 formity, of having the two surfaces entirely plane and exactly 

 parallel to each other, free from scratches and other defects ; 

 the injury to the health of the workmen employed in manufact- 

 uring them, as exhibited in colic, salivation, vertigo, trembling 

 of the limbs, and paralysis, and the comparatively great cost 

 of production, are all obviated by the new process, as it is 

 claimed. The attention of humanitarians has for years been 

 directed toward the discovery and application of some method 

 of remedying the ills caused by the use of mercury, by call- 

 ing into use improved modes of ventilation, adding sodium to 

 the mercury to render it less liable to volatilize, wearing of 

 masks connected with breathing tubes leading to the outside 

 atmosphere, etc., none of them, however, resulting in any im- 

 portant gain in a hygienic point of view. 



Failing to improve sufficiently the mercurial process, atten- 

 tion was directed to the use of other metals, and various 



