1. Twelve ounces of Japan copper were beat into thin plates, and laid _stratum super stratum_ with three ounces of flowers of sulphur, in a crucible. It was exposed in a melting-furnace to a gentle heat, till the sulphureous flames expired. When cold, the æs ustum (_sulphuret of copper_) was pounded, and stratified again; and this process was repeated five times. Mr. Wilson does not inform us whether the powder was mixed with flowers of sulphur every time that it was heated; but this must have been the case, otherwise the sulphuret would have been again converted into metallic copper, which would have melted into a mass. By this first process, then, bisulphuret of copper was formed, composed of equal weights of sulphur and copper. 2. Six pounds of iron wire were put into a large glass body, and twelve pounds of muriatic acid poured upon it. Six days elapsed (during which it stood in a gentle heat) before the acid was saturated with the iron. The solution was then decanted off, and filtered, and six pounds of new muriatic acid poured on the undissolved iron. This acid, after standing a sufficient time, was decanted off, and filtered. Both liquids were put into a large retort, and distilled by a sand-heat. Towards the end, when the drops from the retort became yellow, the receiver was changed, and the fire increased to the highest degree, in which the retort was kept between four and six hours. When all was cold, the receiver was taken off, and a quantity of flowers was found in the neck of the retort, variously coloured, like the rainbow. The yellow liquor in the receiver weighed ten ounces and a half; the flowers (_chloride of iron_), two ounces and three drams. The liquid and flowers were put into a clean bottle. 3. Half a pound of sal enixum (_sulphate of potash_) and a pound and a half of nitric acid were put into a retort. When the salt had dissolved in the acid, ten ounces of mercury (previously distilled through quicklime and salt of tartar) were added. The whole being distilled to dryness, a fine yellow mass (_pernitrate of mercury_) remained in the bottom of the retort. The liquor was returned, with half a pound of fresh nitric acid, and the distillation repeated. The distillation was repeated a third time, urging this last cohobation with the highest degree of fire. When all was cold, a various-coloured mass was found in the bottom of the retort: this mass was doubtless a mixture of sulphate of potash, and pernitrate of mercury, with some oxide of mercury.