Mine Pierrefitte

In August 1875, Boisbaudran observed a pair of violet lines in the spark spectrum of some material he had separated from zinc blende from the Pierrefitte mine, from which he concluded the presence of a new element. This he named gallium in honour of his native country. Later in the year he obtained a small quantity of the free metal by electrolysis of a solution of gallium hydroxide in caustic potash. It was Mendel eff himself who, in November 1875, suggested the identity of this element with eka- aluminium, and further study of its properties and those of its compounds confirmed this view. 

P. E. Lecoq De Boisbaudran, Characteres Chimiques et Spectroscopiques d un Nouveau Metal, le Gallium, Decouvert Dans un Blende de la Mine de Pierrefitte.Valee d Argeles (Pyrenees), Comptes Rendus de VAcademies des Sciences, Paris, 81,493—495, 1875. 

Lecoq directed his interest and energy towards zinc ores. From the Pierrefitte mine in the Argeles Valley, Hautes Pyrenees, Lecoq obtained 50 kg of zinc blende ore and began the examination in 1874. One year later he had reached his goal. He had dissolved a quantity of ore in acid and supposed that he had the element he searched for in solution. He carried out a very simple precipitation reaction. When he put a strip of zinc into the solution, a deposit was formed on the strip. He dissolved the deposit, concentrated the solution and absorbed it in a carbon electrode. For Chemical News he wrote the following description (dted from Mary Weeks) ... 

Paul-Emile Lecoq de Boisbaudran, Chemical and Spectroscopic Character of the New Metal Gallium, Discovered in the Blende of the Mine of Pierrefitte in the Valley of Argeles in the Pyrenees, Chemical News 32 (1875) 159 idem, On certain properties of Gallium, Chemical News 32 (1875) 294. 

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