When a plate of copper is kept immersed in mercury for some time, the mercury adheres to its surface in a small degree and is not easily rubbed off; the plate is rendered brittle by it and the fracture has a brilliant mercurial appearance; but a low red heat expels the mercury and the copper resumes its colour and tenacity, with scarcely any loss of weight, being only about 5½ per cent. in two or three trials. Recently precipitated copper in powder, dried and triturated with mercury, produced no union. Neither did Dutch-leaf (which is copper with a very little zinc) unite with mercury by trituration. Mercury precipitated from deutonitrate by a plate of copper gave pure running liquid. The plate of copper appeared as if it had been immersed in mercury, was brittle with a shining fracture, but recovered its colour and texture by heat, and lost scarcely any weight. The method recommended by Boyle was tried: 2½ parts of crystallized verdigris, 2 parts of mercury and 1 of common salt, were triturated together till the mercury disappeared, the powder was then digested awhile with vinegar over a fire and frequently stirred. The mass was then put on a filter and dried. It contained a little fluid mercury, but was chiefly composed of acetate of copper and oxide or muriate of mercury. The liquid contained acetate of copper and muriate of soda. From the above it is manifest that mercury has some chemical action upon copper; but it has not yet been found, I apprehend, that the two metals unite so as to form a proper amalgam. 5. _Mercury and iron._ These two metals have little if any affinity for each other. I do not know that any chemical combination of them has ever been formed. 6. _Mercury and tin._ These two metals readily combine, especially if assisted by heat. I heated 52 parts of tin and 167 of mercury together, that is, 1 atom of each, till they united in a fluid mass. The amalgam crystallized in about 180°. By hard pressure in the hand nearly 50 parts of fluid mercury were separated from the amalgam when cool, containing in appearance very little tin. After this an amalgam was formed of 104 parts of tin and 167 mercury (2 atoms tin to 1 mercury); this congealed about 230°, and remained a hard, dry, crystalline substance, agreeing in appearance with that which adheres to mirrors. For the purpose of silvering mirrors however much more mercury is employed than is indicated by the above proportion; but after the glass is slid upon the tinfoil previously covered with mercury, a great pressure is applied, which expels the superfluous mercury nearly in a state of purity.