The sulphur issues as sulphuretted hydrogen, mixed with the nitrogen of the air.

Generally speaking, the sulphuretted hydrogen and sodium sulphite methods are to be preferred.

Disengages sulphuretted hydrogen when fresh.-Thiswater was inodorous when the bottle was opened.

Boil till dissolved, dilute, and precipitate the tin with sulphuretted hydrogen.

There are now two small pools which exhale carbonic acid gas and sulphuretted hydrogen.

Allow to settle, filter off the zinc sulphide and wash with sulphuretted hydrogen water.

Pass sulphuretted hydrogen, warm, and allow the precipitate to settle.

How can we explain the origin of the sulphuretted hydrogen?

Filter through a coarse filter, wash with hot water containing sulphuretted hydrogen, if necessary.

Is this sulphuretted hydrogen mixed with a great proportion of carbonic acid or atmospheric air?

It forms a yellow fusible mass, which is decomposed by water into alumina and sulphuretted hydrogen.

The ammonia and sulphuretted hydrogen are almost entirely dissolved by the water used in the gas generator.

The precipitate will contain the phosphorus, together with any arsenic acid not reduced by the sulphuretted hydrogen.

These are nitrogen, carbonic acid gas, and the destructive sulphur compounds, sulphuretted hydrogen and carbon bisulphide vapour.

Thioaldehydes are also known, and are obtained by leading sulphuretted hydrogen into an aqueous solution of acetaldehyde.

Pass sulphuretted hydrogen, boil, cool, and filter.