Young's Demonstrative Translation of Scientific Secrets

ulphate of copper, add a solution of ferrocyanide of pottasium, so long as a precipitate continues to be formed. This is allowed to settle, and the clear liquor being decanted the vessel is filled with water, and when the precipitate settles the liquor is again decanted, and continue to repeat these washings until the sulphate of potash is washed quite out; this is known by adding a little chloride of barium to a small quantity of the washings, and when there is no white precipitate formed by the test, the precipitate is sufficiently washed. A solution of cyanide of potassium is now added to this precipitate until it is dissolved, during which process the solution becomes warm by the chemical re-action which takes place. The solution is filtered, and allowed to repose all night. If the solution of cyanide of potassium that is used is strong, the greater portion of the ferrocyanide of potassium crystalises in the solution, and may be collected and preserved for use again. If the solution of cyanide of potassiu