Art. LVI.—On the Bromine Method of Estimating Sulphur in Gaseous Compounds.

By Dr. W. P. Evans.

[Read before the Philosophical Institute of Canterbury, 30th November, 1896.]

A Slight modification of the well-known Harcourt method of estimating sulphur in coal-gas seems capable of rendering-good service in the analysis of gaseous substances in general.

For coal-gas a very simple form of apparatus gives excellent results. The gas is passed at the rate of about 25 litres per hour through any convenient form of absorption-flask; then through a combustion-tube packed for about 6in. of its length with platinised asbestos, and kept at a good red heat; and lastly through a second absorbing-flask (Winkler spirals or ordinary 10-bulb tubes answer extremely well as absorbing-flasks). The two flasks are charged with bromine water acidulated with hydrochloric acid. The first flask gives-those sulphur compounds -which are directly oxidized by bromine water, the second those which are only oxidized after passing the layer of heated platinum.

In coal-gas this practically means that No. 1 gives the sulphuretted hydrogen and No. 2 the carbon-bisulphide. If, as is generally the case, only the total sulphur is needed, then the first absorbing-flask is, of course, to be omitted. The apparatus, once set up, needs no further attention. The only precipitate is the well-known barium-sulphate, and the results-obtained are more than accurate enough for. any technical purpose.