Page:Proceedings of the Royal Society of London Vol 60.djvu/426

394 from these and heated in the oxyhydrogen flame, gave the gallium line \ 41716. The ingots were exceedingly hard, and practically resisted all attempts to reduce them to small pieces. One ingot, weighing 210 grams, was boiled with hydrochloric acid, until its solvent action on the metal had nearly ceased, when the liquid was decanted, and fresh acid poured on. The process was very slow, and, after 80 grams had been dissolved, the remaining piece of metal was scraped, to remove an adhering layer of carbonaceous matter, and the analysis of the products proceeded with. The liquid was filtered, and the black residue A washed. The filtrate was evaporated, to expel the excess of hydrochloric acid, water was added, and the solution, not being clear, was filtered. The residue thus obtained had, when dry, a dark greyish colour. Residues A and B.

In the clear filtrate two rods of zinc were immersed, and during a period of one hour and three-quarters hydrogen was evolved, and metals were deposited on the zinc. The deposit was scraped off, and separated from the liquid by filtration. Metallic deposit To the filtered solution* were added about 4 c.c. of lead acetate solution, and two rods of zinc were placed in the liquid, according to the method of Lecocq de Boisbaudran,* by which, as the lead is precipitated, traces of other metals, such as copper, silver, indium, thallium, &c., are collected by the lead. Metallic precipitate F.

Fractional Precipitation by Ammonium Acetate.—The filtrate, in volume about 2 litres, was boiled, but as no precipitate formed, 15 c.c. or thereabouts of a solution of ammonium acetate were slowly added, and the solution boiled; the iron, being in the ferrous state, was retained in solution, whilst it was expected that the gallium would be precipitated as phosphate. After boiling for about twenty minutes, the substances precipitated were collected on a filter and washed. Residue D.

The filtrate was again boiled with about 10 c.c. of ammonium acetate, and the precipitate collected on a filter. Residue E.

Further Precipitation of Basic Acetates.—The filtrate from E was again boiled with ammonium acetate, the resulting precipitate being filtered off. It was much darker in colour than those previously obtained. Sesquioxide metals G.

The filtrate was evaporated until it became a saturated solution of ferrous chloride. It was allowed to cool and crystallise, and the operation was repeated upon the mother liquor. The two crops of crystals were mixed with others, which were obtained as follows. The solution from the remaining portion of the 210 grams of metal was filtered, and the filtrate evaporated. It was then allowed to cool and crystallise. The mother liquor was concenlrated, and again allowed to cool and crystallise, the differeut crops of crystals


 * ‘ Spectres Lumineux.’