InteUi"ence and Miscellaneous Articles. 



87 



If chloride of chrome be saturated with ammoniacal gas, the com- 

 bination sometimes takes place with ignition; the vessel is filled with 

 a purple red light, which continues till the chrome is saturated. 



Metallic chrome may be obtained in a still simpler manner, by re- 

 ducing chloride of chromium with ammoniacal gas in the same way; 

 the metal is not then black, but of a chocolate-brown colour. 



The preparation of chloride of chromium is so well known, that it 

 would appear superfluous to say anything more about it if it were 

 not in itself interesting. When a neutral solution of oxide of chrome 

 in muriatic acid is evaporated, there is obtained, as is well known, a 

 green mass, which does not alter at the temperature of boiling water, 

 and even at some degrees above it; but when the temperature is 

 very considerably raised, it begins to swell, and losing water is con- 

 verted into a spongy crystalline brilliant mass, of a peach. blossom 

 colour, which may be taken for a sublimate; but it is not one, for this 

 compound is not volatile. The conversion of a muriate into a chloride 

 cannot be shown in a more convincing manner by any other com- 

 bination. 



When the chloride of chrome is calcined in contact with the air, it 

 is converted into a green oxide; but the colour is so fine that it may 

 be interesting for the manufacturers of porcelain to be more parti- 

 cularly acquainted with the fact. 



If sulphuretted hydrogen gas be passed over chloride of chrome, a 

 brilliant black crystalline sulphuret of chrome is obtained. 



Metallic chrome prepared in the manner above described, does not 

 alter at a red heat; nor does it by continued calcination become 

 green, which, however, might be expected to happen if the metal 

 contained any admixture of chloride. 1 have not further examined 

 whether the oxide obtained differs in its composition from common 

 green oxide. If chloride of chrome be fused in proper proportion 

 with muriate of ammonia and carbonate of soda, metallic chrome is 

 not obtained, according to Wohler, but protoxide of chrome, in 

 crystalline scales, and green transparent crystals of common salt, 

 which have a fine green colour, and apparently combined with 

 chloride of chrome. — Ann. de Chmi, el de Plitjs. xlviii. 



LUNAR OCCULTATIONS FOU JULY. 

 Occidtalions of Planets and fixed Stars by the Moon, in July 

 1832. Computed for Greenwich, by Thomas Henderson, Esq. ; 

 and circulated bij the Astronomical Society. 



