Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/240



2. With a view to repeat and vary the last experiment, another portion of residue, also weighing 50 grs. was thrown into a solution of neutral carbonat of ammonia, the quantity of the latter being more than sufficient to saturate any acid present, and to dissolve the magnesia suspected to exist in that residue. A considerable effervescence took place. The mixture, after this, was gently heated and filtered. The residue left in the filter was of a pale yellowish-brown colour. The dear solution deposited on standing a small quantity of precipitate similar to the residue left in the filter, to which residue this precipitate was added. The contents of the filter were then treated with potash, in the manner before described (§ VIII. 1), in order to separate the alumine, after which the residue (now supposed to contain nothing but carbonat of lime and iron) was treated with dilute muriatic acid, which dissolved it with effervescence. From this solution, the lime was precipitated by oxalat of ammonia, and the remaining liquor, now containing nothing but muriat of iron, was treated with carbonat of ammonia, so as to precipitate the whole of the iron, which, in subsiding, assumed a pale reddish colour. The clear fluid being decanted off, and the precipitate