Prof. Doremus's Lectures. A Neat Mode of Making Orpiment.

Scientific American 1, 2.1.1865

Prof. Doremus explained that chlorine has so strong an affinity for hydrogen that it will take that element from many of its compounds. To illustrate this he introduced a little arseniuretted hydrogen gas under the mouth of a tall inverted bell glass filled with water, when the gas, of course, rose to the top, displacing its own volume of the water. Some sulphuretted hydrogen gas was then poured in the same way up the same glass. On adding some chlorine gas to the mixture, the chlorine took the hydrogen from both the arsenic and the sulphur, when tose two elements entered into combination as the sesquisulphuret of arsenic, or yellow orpiment. The hydrogen and chlorine combined to form hydrochloric acid gas, which was absorbed by the water.