to the coating. It is probable that a solution of silver of this kind might be applied in some cases in the arts, to the purposes of ornament and utility.
Combination of Ammonia with Chlorides[1].
It has been already shown, particularly by Sir H. Davy, that several of the binary compounds of chlorine, as those of phosphorus, tin, &c., exert a strong affinity for ammonia, condensing it when in the gaseous state, and neutralizing its alkaline properties. The combinations which will here be offered to notice are of a different kind, and if they deserve any attention, it will be in consequence of the weakness of the power which is exerted in their formation, and the slight change of properties induced on the substances by union.
It has been frequently observed by chemists, that if well-fused chloride of lime be placed in ammoniacal gas, there is a rapid absorption of the gas, and the chloride becomes covered with a white powder. If ammonia be repeatedly added until the absorption ceases, the mass of chloride swells, cracks, splits in all directions, and at last forms a white pulverulent substance.
Exposed to the atmosphere, it deliquesces, but not so rapidly as chloride of lime. Thrown into water it dissolves, forming a strong alkaline solution. Heated, it gives off ammonia, and the chloride remains unchanged. Placed in chlorine it inflames spontaneously, and burns with a pale yellow flame.
The fused chlorides of barium and strontium suffer a very slight change in ammoniacal gas in many days; after more than a fortnight, the chloride of strontium, weighing about 30 grains, had absorbed only a cubical inch of gas, and a slight efflorescent appearance was seen on the broken edge.
A piece of fused chloride of silver, weighing about 80 grains, placed in ammoniacal gas, gradually absorbed more than 40 cubical inches. The action took place over the whole surface of the mass, but most speedily at the fractured edges. The chloride swelled considerably, and crumbled into powder. The substance formed was at first white, but it
- ↑ Quarterly Journal of Science, v. 74.
