COMBINATION OF SULPHUR WITH ALCALIES.

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Experiment I.

Preparation of sulphuret of potash and soda.

If potash or soda he melted by a moderate heat, with equalparts of sulphur, in a covered crucible, a mass is obtained whichafter cooling exhibits a liver-brown colour. It is called sulphuretof potash or soda according to the alcali made use of.

This combination unites with gold both in the dry and humidway. To exhibit this, some leaf gold may be digested with heat,in a concentrated solution of sulphuret of potash.

Experiment II.

Preparation of sulphuret of ammonia.

Ammonia also combines with sulphur; sulphuret of ammoniamay be obtained in the following manner :

Two parts of finely powdered lime are put into a dry retort,upon this one part of muriate of ammonia well mingled by tritu-ration with one-third part of sulphur is poured, and the wholemingled together by shaking. The charged retort is then placedin a sand-heat, a receiver containing a little water is adopted,and the distillation carried on very slowly. The fluid whichpasses over on increasing the heat is sulphuret of ammonia. Itis ot a deep yellow colour, a volatile and disagreeable odour, andfumes strongly in contact with air. In order to obtain sulphuretof ammonia very fuming, the first fluid which passes over mustbe kept separate, for it is only this which is smoking, by reasonof its containing some uncombined ammonia. In other respectsit* properties are like the former combinations of sulphur withalcalies. Its volatility renders it capable of restoring oxidatedmetals to the metallic state as may be evinced in the following

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