402 Foreign and Miscellaneous Intelligence. 



When the sublimed chloride is used, the metal is often in very 

 beautiful crystalline groups. 



The parts of the tube which are last heated are frequently plugged 

 up with muriate of ammonia : it is useful, therefore, to introduce a 

 smaller tube, and clear away the muriate from time to time which 

 attaches to it. 



Perhaps tungsten and molybdenum may be thus reduced ; but all 

 similar trials upon silica and alumina have failed *. 



10. PREPARATION OF METALLIC CROMIUM. (Liebig.") 



When ammoniacal gas is passed, in a similar manner to the above, 

 over the chloride of chromium and ammonia, heated to redness in a 

 glass tube, metallic chromium is obtained as a black pulverulent 

 metallic powder, assuming lustre when burnished, inflaming at a red 

 heat, and burning into a brown powder. 



When ammoniacal gas is passed over the chloride of chromium, the 

 combination occurs with the disengagement of light, the vessel is 

 filled with a purplish red flame, which continues until the chloride is 

 saturated. When the chloride of chromium is heated in ammoniacal 

 gas, the metal is also obtained, but is then of a brown chocolate 

 'colour instead of black. 



When in the preparation of chloride of chromium the neutral solu- 

 tion of muriate of chromium is evaporated, a green mass is obtained, 

 which evolves no water at temperatures even a little above 212F. 

 But at temperatures of 400 or 500 F., it begins to smell, and 

 losing water, becomes a brilliant spongy crystalline peach-coloured 

 mass, perfectly fixed in the fire. The conversion of a muriate into a 

 chloride cannot be so convincingly shown on any other substance. 



When the chloride is heated in the air, a very beautiful oxide of 

 chrome, as to colour, is obtained, fit for porcelain works. 



When chloride of chromium is heated in sulphuretted hydrogen, a 

 crystalline brilliant black sulphuret of chromium is procured. 



Metallic chromium, prepared as described, burns, if calcined, in the 

 air, but does not become of a green colour : the oxide thus procured 

 has not been examined, to ascertain whether it be the same with, or 

 a different oxide from the green one f. 



11. ANALYSIS OF SOME MERCURIAL SALTS. 



Mr. Phillips has recently examined and analysed some of the salts 

 of mercury, especially some sulphates and carbonates. When 

 two parts of mercury and three of sulphuric acid are heated for a 

 short time, some protosulphate of mercury is formed, but on con- 

 tinuing the heat, almost the whole becomes bipersulphate. This, 

 being put into water, is decomposed, and the yellow precipitate, for- 

 merly called turpetli mineral, thrown down. When 200 parts of 

 the bipersulphate were put into water, 141.1 parts, and then by heat 



* Ann. de Chimie, xlvii. 108. f Ibid., p. 1 10. 



