466 MISCELLANEOUS CHEMISTRY. 



continuing the action of electricity for a longer or shorter period. That 

 the metal is actually volatilized is proven by examination with the spectro- 

 scope during the progress of the operation, the characteristic lines of what- 

 ever metal is used for the electrode being fully revealed. This may be 

 classed as the discover}^ of a new art, and is certainly very interesting and 

 remarkable. In brief, it consists in plating the surfaces of substances with 

 metals, by exposing such surfaces to the hot vajjors of whatever metal it i& 

 desired to plate with. 



Professor "Wright has already made a number of valuable jDractical appli- 

 cations of his discovery. He produces mirrors with silver, platinum, iron, 

 and other metals, of the most pure and resplendent character. He deposits 

 gold in/ a layer so thin that it is only 0.000183 mm. in thickness, or approx- 

 imately only one-fourth the wave length of a red ray of light. He obtains 

 curious colors in the metals,'varying with the thickness of the dej)0sits, and 

 opens up a new field for investigation into the nature of metals and other 

 volatilizable substances, and perhaps of light. He shows that his electric- 

 ally deposited metals have improved qualities ; that telescopic and heliostatic 

 mirrors, for example, of platinum deposited on silver, by his process, will 

 be unaltei^able ; and the promise is that we shall before long be able by this- 

 new art to produce telescopes and other scientific instruments of greatl}^ 

 improved character. — Scientific Americmi. 



The residual charcoal after lixiviation of destructively distilled sea-weed, 

 possesses an extraordinary power of absorbtion and deodorization. Accord- 

 ing to Mr, E. C. C. Stanford, its composition is about midway between that' 

 from wood and that from bone, in the proportion of carbon ; but it is more 

 nearly like the latter, from which it differs in containing more carbon and 

 carbonates of calcium and magnesium, and less phosphates. It can be ob- 

 tained at about one-fourth the price of any other charcoal. 



Polishing Brass. — For polishing the brass work of engines, rub the sur- 

 face of the metalwith rottenstone and sweet oil, then rub off with a piece 

 of cotton flannel and polish with soft leather. A solution of oxalic acid 

 rubbed over tarnished brass soon removes the tarnish, rendering the metal 

 bright. The acid must be washed off with water, and the brass rubbed 

 with whiting and soft leather. A mixture of muriatic acid and alum dissolved 

 in water imparts a golden color to brass articles that are steeped in it for a 

 few seconds. — Scientific American. 



Bismuth has been purified by Mr. E. Smith in this way : To every six- 

 teen parts of bismuth kept in a fluid state, at the lower point of its fusing 

 temperature he added one part of mixture composed of three parts of 

 flowers of sulphur and eight parts of cyanide of potassium. The bismuth 

 was kept melted for fifteen minutes after the mixture was introduced and 

 then allowed to cool. 



