178 Scientific Intelligence. 



at a temperature by no means elevated ; but in order to render it completo 

 and fuse the antimony, the glass should be made red hot, and kept in that 

 state for five or six minutes. The temperature at the close of the process 

 may with advantage be increased to bright redness by the use of the 

 blowpipe. 



The appearance of the metal within the tube depends upon the manner 

 of conducting the experiment. If the sulphuret had been placed in a heap, 

 the metal is found partly in a spongy state, and partly in minute globules ; 

 but if it had been diffused over a considerable space, no globules appear, 

 and the metalhc lustre is indistinct. The metallic nature of the spongy 

 mass may, in general, be brought distinctly into view by placing it on a 

 piece of white paper, and pressing it with the nail or the blade of a pen- 

 knife. 



The result also depends on the velocity with which the hydrogen is 

 transmitted through the tube. If the gas passes rapidly, some of the 

 metal is hurried off at the moment of separation from the sulphur, and is 

 deposited within the tube as a metallic film, which is sometimes very dis- 

 tinct. If, on the contrary, the passage of the gas is slow, this appearance 

 does not take place. 



By means of this process, I have succeeded in procuring from the tenth 

 of a grain of the sulphuret metallic antimony, the lustre of which could be 

 distinctly seen with the assistance of a lens. From half of the precipitates 

 procured from the mixture of two grains of tartar emetic with broth and 

 milk, I procured distinct metallic globules. 



Should a considerable quantity of animal or vegetable matter subside 

 with the sulphuret, the metallic antimony will then be so mixed with char- 

 coal that its lustre cannot be seen distinctly. This occurred to me in de- 

 composing the sulphuret obtained from porter. In a case of this kind the 

 mixture should be placed in an open tube, and heated to redness by means 

 of a spirit lamp. The antimony is then oxidized, and the oxide, which 

 attaches itself to the cool parts of the tube in form of a white powder, may 

 be recognized by its appearance and volatility. 



20. Ultimate analysis of several vegetable substances. — By M. F. Mar- 

 CET. {An. de Ch. et de Ph. vol. xxxv.) The mode of analysis employed 

 by M. Marcet is that which was introduced by M. Gay-Lussac and The- 

 nard. It consists in mixing the substances to be analyzed with peroxide 

 of copper and heating the mixture to redness. Its composition is calculat- 

 ed from the loss of weight experienced by the oxide of copper, and the 

 quantity of water and gas which are collected, the substance having been 

 previously dried by exposure to the action of sulphuric acid under the ex- 

 hausted receiver of the air-pump. 



Starch in its common state, and modified by heat, (Amidine of Cavcn- 

 tou) is thus constituted :— 



Common starch. Torrefied starch. Starch from malt. 



Carbon, 43.7 35.7 41.6 



Oxygen, 40.7 58.1 51.8 x 



Hydrogen, 6.6 6.2 6.6 



