On the Occurrence of Gallium in Clay-ironstone. 407 



An estimation of the gallium in the " mixer metal " had been at- 

 tempted 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 ferrocyanide method. 



The gallium was separated from the iron by pure sodium hydrate, 

 and finally precipitated as hydrate and ignited. The oxide weighed 

 0'0149 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 Luderich mine. MM. Lecocq de Boisbaudran and Jungfleisch 

 extracted 62 grams of crude gallium from 4300 kilograms, or nearly 

 4^ 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, bat cannot 

 include the details of our later work in the present communication. 



