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On the purification of mercury
228
Ed~or~l.
On t h e P u r i f i c a t i o n of Mercury.--BY PROF. ALBERT R~ LEEDS.--In investigations carried on inphysical laboratories, and in~ the volumetric analysis of gases, a large quantity of mercury is employed, and as it is very readily contaminated, a method for its rapid and convenient purification is important. Such a method must provide for the removal of the three kind of impurities which arc usually present : First, foreign metals, especially lead, zinc~ and tin ; secondly~: common dirt and dust ; and thirdly, watcr or other liquids.
The most convenient device hitherto employed was a long glass: tube~ into which the mercury was poured through a paper funnel, thefunnel having a pin hole at the bottom, and serving to retain the dirt, and dust. The tube was partly filled with dilute nitric acid, and was~ provided with a stop cock below, or with a bent tube, so that a s h o r t column of mercury might balance a long column of" acid. The device herein recommended consists of a glass funnel, A, ca-
Items and Novelties.
2"29
pable of holding five or ten pounds of mercury, the tube of which is cut off at a point just below the stopper of the bottle, B. Cottor~ wool is jammed into the tube until it fills up the neck, and bulges out at the bottom of the funnel. A short glass tube bent at right angles~ passes likewise through the india rubber stopper, and is connected with a water air pump. The bottle is two-thirds filled with dilute nitric acid, (one part of acid and four or five parts of water). The ~ impure mercury poured into the funnel, _4, is drawn through the cotton plug in a multitude of streams, and passes as a fine rain through the acid below. The foreign metals, if not in too large quantities, are removed by solution in the acid, and the pure mercury collects below. It is then run off through the stop cock into a second funnel C~; and, after being thoroughly dried by suction through another plug o f cotton wool, it is caught and preserved in the bottle, D. A short time suffices for the almost automatic purification of a large quantity of mercury.mFrom the Scientific .4merican. Stevens' institute of Technology, x~ebruary, 1874:.
Comparative Value of Artificial A l i z a r i n e a n d Madder~ wThe growing importance of the manufacture of artificial alizarinc has several times of late been referred to in the Journal, as well as the probable effect of this increase on the cultivation of the madder~ To such proportions has the alizarine manufacture attained, that theprevailing opinion has been to the effect that the near future would, witness the total extinction of the madder culture. In a recent report, however, of the Soci~t~ Industrielle de Mulhouse, a somewhat different view is taken from that generally held. The report maintains that the large demand for artificial alizarine~ will not seriously or permanently affect the normal consumption of madder; or, in other words, the proportion of pure madder used in~ the arts, before the introduction into commerce of extracts of madder r will remain unchanged. The artificial a|izarlne comes into competition with these extracts, but only to a limited extent; for it is declared that, while the violet shades which it produces are of superior beauty and brilliancy to those of the extracts, the reds it affords are inferior. It seems that in the natural product there is a second coloring principle, namely, purpurine--to the presence of which the production of the fine orange reds is attributed. It has thus far been found impossible to reproduce the purpurine by artificial means; indeed, its
Ed~or~l.
On t h e P u r i f i c a t i o n of Mercury.--BY PROF. ALBERT R~ LEEDS.--In investigations carried on inphysical laboratories, and in~ the volumetric analysis of gases, a large quantity of mercury is employed, and as it is very readily contaminated, a method for its rapid and convenient purification is important. Such a method must provide for the removal of the three kind of impurities which arc usually present : First, foreign metals, especially lead, zinc~ and tin ; secondly~: common dirt and dust ; and thirdly, watcr or other liquids.
The most convenient device hitherto employed was a long glass: tube~ into which the mercury was poured through a paper funnel, thefunnel having a pin hole at the bottom, and serving to retain the dirt, and dust. The tube was partly filled with dilute nitric acid, and was~ provided with a stop cock below, or with a bent tube, so that a s h o r t column of mercury might balance a long column of" acid. The device herein recommended consists of a glass funnel, A, ca-
Items and Novelties.
2"29
pable of holding five or ten pounds of mercury, the tube of which is cut off at a point just below the stopper of the bottle, B. Cottor~ wool is jammed into the tube until it fills up the neck, and bulges out at the bottom of the funnel. A short glass tube bent at right angles~ passes likewise through the india rubber stopper, and is connected with a water air pump. The bottle is two-thirds filled with dilute nitric acid, (one part of acid and four or five parts of water). The ~ impure mercury poured into the funnel, _4, is drawn through the cotton plug in a multitude of streams, and passes as a fine rain through the acid below. The foreign metals, if not in too large quantities, are removed by solution in the acid, and the pure mercury collects below. It is then run off through the stop cock into a second funnel C~; and, after being thoroughly dried by suction through another plug o f cotton wool, it is caught and preserved in the bottle, D. A short time suffices for the almost automatic purification of a large quantity of mercury.mFrom the Scientific .4merican. Stevens' institute of Technology, x~ebruary, 1874:.
Comparative Value of Artificial A l i z a r i n e a n d Madder~ wThe growing importance of the manufacture of artificial alizarinc has several times of late been referred to in the Journal, as well as the probable effect of this increase on the cultivation of the madder~ To such proportions has the alizarine manufacture attained, that theprevailing opinion has been to the effect that the near future would, witness the total extinction of the madder culture. In a recent report, however, of the Soci~t~ Industrielle de Mulhouse, a somewhat different view is taken from that generally held. The report maintains that the large demand for artificial alizarine~ will not seriously or permanently affect the normal consumption of madder; or, in other words, the proportion of pure madder used in~ the arts, before the introduction into commerce of extracts of madder r will remain unchanged. The artificial a|izarlne comes into competition with these extracts, but only to a limited extent; for it is declared that, while the violet shades which it produces are of superior beauty and brilliancy to those of the extracts, the reds it affords are inferior. It seems that in the natural product there is a second coloring principle, namely, purpurine--to the presence of which the production of the fine orange reds is attributed. It has thus far been found impossible to reproduce the purpurine by artificial means; indeed, its