Page:Proceedings of the Royal Society of London Vol 60.djvu/439

Rh An estimation of the gallium in the “ mixer metal ” had been attempted in the spring of this year, but the separation was not as complete as in the process just described. The figure obtained, however, is so closely in accord -with the above that we will briefly describe the process and record the result.

The sample, weighing 340 grams, was boiled with hydrochloric acid until the latter was nearly neutralised ; the solution was then decanted, and fresh acid added to the residue. When the acid ceased to have any marked action the whole liquid was filtered, and the residue A washed, dried, and treated separately for the separation of gallium.

Filtrate B.—From this filtrate gallium was precipitated by calcium carbonate, but phosphates and sesquioxide metals, including chromium, rendered the precipitate a too complex mixture, and we had recourse to the ferrocjanide method.

The gallium was separated from the iron by pure sodium hydrate, and finally precipitated as hydrate and ignited. The oxide weighed 00149 gram, and this amount corresponds to 0'0033 per cent, of gallium in the sample or one part in 30,000 of the iron.

We know, by the spectrographic examination of the residues, &c., that the whole of the gallium was not obtained, and that the oxide weighed was not quite pure gallium oxide, but with the experience gained in this estimation we were able to make the more exact analysis already described.

In conclusion, we may state that this blast furnace metal contains more gallium than the richest source of that element hitherto known. The mineral referred to is a zinc blende from Bensburg on the Rhine, about eight miles from Cologne ; it is found in the Franzisca adit of the Liiderich mine. MM. Lecocq de Boisbaudran and Jungfleisch extracted 62 grams of crude gallium from 4300 kilograms, or nearly tons of the ore; this is in the proportion of 1 in 72,000, but they believed the actual quantity present to be about 1 part of gallium in 50,000 of the ore.

We have recently discovered other sources of gallium, but cannot include the details of our later work in the present communication.