Zinc possesses but a small degree of malleability and ductility, except under certain circumstances. When broken, it appears of a shining blueish white; and when exposed to the air, becomes covered with a pellicle which reflects various colors. If beaten out into thin leaves, it will take fire from the flame of a common taper. Its filings are mixed with gunpowder, to produce those brilliant stars and spangles which are seen in the best artificial fire-works. It is also one of the metals employed to form Galvanic batteries. It is the most combustible metal we have. It will decompose water without the assistance of heat. Next to manganese, it has the strongest affinity for oxygen of all the metals. Its specific gravity is 6.861. Its nature is such, that it seems to form the link between brittle and malleable metals. Some mineralogists consider zinc to be the most abundant metal in nature, excepting iron. Calamine, or lapis calaminaris, which is a native oxide of zinc, combined with carbonic acid, is found both in masses and in a crystallized state, and is generally combined with a large portion of silex. Zinc is also found in an ore called blend, in which state it is mineralized by sulphur. The miners call it Black Jack—a mineral employed till lately in Wales for mending the roads. Zinc is generally called by our artists spelter; and in England and elsewhere it is extracted from calamine, and other ores, by distillation. This metal abounds in China, where it is used for current coin, and for that purpose is employed in the utmost purity. These coins have frequently Tartar characters on one side, and Chinese on the other. They have generally a square hole in the centre, that they may be carried on strings, and more readily counted.
Antimony is of a dusky white color, brilliant, brittle, and destitute of ductility. Though seemingly hard, it may be cut with a knife. Its specific gravity, according to Bergman, is 6.86. It is procured from an ore which is found chiefly in Hungary and Norway. Native antimony, alloyed with a small portion of silver and iron, has been found in Sweden. And it is said, that it has been found in the state of Connecticut, in America, nearly in a pure metallic form. There are five distinct ores of antimony, but the grey is the only one found in sufficient quantity for the manufacturer; it is a sulphuret of antimony. Perhaps we have no metal more valuable as a medicine than this, or one which is applied in such various ways.
Bismuth is of a yellowish white color, lamellated texture, and moderately hard, but not malleable. It is so brittle that it breaks readily under the hammer, and may be reduced to powder. It has the singular property of expanding as it cools. Hence, probably, its use in the metallic composition for printers’ types; as from this expansive property are obtained the most perfect impressions of the moulds in which the letters are cast. In manufactories this metal is known to the workmen by the name of tin glass. It is one of the metals which will inflame when suspended in oxymuriatic acid gas. It is generally found with cobalt in the cobaltic ores of Saxony and England. Native bismuth, and sulphuret of bismuth, are found on the continent; and a sulphuret of bismuth has been discovered in Cornwall; but this is not an abundant metal. If 8 parts of bismuth, 5 of lead, and 3 of tin, be melted together, the mixed metal will fuse at a heat no greater than 212°. Tea-spoons made of this alloy are sold in London, to surprise those who are unacquainted with their nature. They have the appearance of common tea-spoons, but melt as soon as they are put into hot tea.
Arsenic, when reduced to its pure metallic state, is a friable brilliant metal, of a blueish white color, easily tarnishing, or oxidizing, by exposure to the air. In all its states it is extremely poisonous. It may be known by the smell of garlic, and by the white fumes which it exhales when thrown upon a piece of red-hot coal. Its specific gravity is 8.310. It is found in Bohemia, Hungary, Saxony, and other places on the continent; and in combination with acids, sulphur, or oxygen. The arsenic of commerce is prepared in Saxony, in the operation of roasting the cobalt ores for the manufacture of zaffre. The reverberatory furnace in which the ores are roasted terminates in a long horizontal chimney; and in this chimney the arsenical vapors are condensed, forming a crust, which at stated times is cleared off by criminals, who are condemned to this work.
Cobalt is a whitish-grey, brittle metal, nearly resembling fine hardened steel; is difficult of fusion, but obedient to the magnet. According to Bergman, its specific gravity is about 7.700; though Tassaret makes it 8.538. Formerly all our cobalt came from Saxony. The cobalt ores of Hesse produce a nett profit of £14,000 a year, as stated in Born’s Travels; though once they were used for no other purpose than to repair the roads. But now cobalt is found abundantly in the Mendip hills in Somersetshire, and in a mine near Penzance in Cornwall. Zaffre is now made from the cobalt ores found in these hills. Had it not been for the rapid promulgation of chemical science in these kingdoms, this important metal might have lain in the bowels of the earth undiscovered for ages yet to come. Formerly miners not only threw cobalt aside as useless, but they considered it so troublesome when they found it among other ores, that, as stated in Beckmann’s History of Inventions, a prayer was used in the German church, that God would preserve miners from cobalt and from spirits. It is now very valuable to the manufacturers of porcelain.
Manganese is of a dark grey color, brilliant, very brittle, of considerable hardness, and difficult fusibility. Its specific gravity has been estimated by Bergman at 6.850, and by Hielm 7.00. It is never found native. It was first procured in its pure metallic form by Kaim and Gahn between 1770 and 1775. It abounds in America, and in various parts of the continent. The manganese which is used in England, is obtained in a state of black oxide from Somersetshire and Devon. It is found either in the state of an oxide or a salt. But the discovery of mines of it in this country is a new acquisition, owing to the spirit of chemical research. Dr. William Dyce, of Aberdeen, has lately communicated to the Society for the Promotion of Arts, &c., the discovery of a mine of great extent, and very fine quality, in the vicinity of that town: for which the gold medal of the Society was sent him. Professor Beattie, of the same place, has also discovered manganese in his neighborhood, on the river Don, of good quality. Scheele discovered this metal in the ashes of burnt vegetables. Proust has lately announced the discovery of a native sulphuret of manganese. That from the Bristol and the Mendip hills generally contains lead.
Tungsten is a heavy metal, but its properties are not much known. It is procured from a mineral found in Sweden, and from an ore called wolfram, found in Cornwall, Germany, &c. It has been used in France for making vegetable lakes; but is not used here. Though it has been recommended as a proper basis for colors, it shows in some instances a strange fugacious disposition. Its specific gravity is 17.60.
The same may be said of the other metals, their properties not being much known. Molybdenum was first procured in a metallic state by Hielm, in the year 1782; and, it is believed, has been employed in some processes of dyeing in Germany. As the ore may be had in great plenty, it will probably, some time hence, come into general use here. At present it is not used in any of the arts. Its specific gravity is 8.61. Uranium was discovered by Klaproth in 1789, in a mineral called pechblend; and has since been found combined with carbonic acid, in the common green mica. Titanium was first noticed in the year 1781, by Mr. Macgregor, in a greyish black sand, found in the vale of Menachan in Cornwall; but has since been discovered by Klaproth in several other minerals. An ore of it occurs in Transylvania, which very much resembles yellow sand. This metal has been used in France for painting porcelain. Tellurium was discovered by Klaproth in the year 1798, in a particular kind of gold ore. It has hitherto been found in quantities too small to allow of its being employed in the arts. Its specific gravity is only 6.115. Chromium received its name from a property it has of imparting a lively color to a variety of other bodies. The emerald is colored by an oxide of this metal. Columbium was discovered in a mineral sent from Massachusetts in North America. Tantalium was found in an ore from Swedish Lapland: but Dr. Woollaston has lately discovered that this and columbium are identically the same metal. Cerium had not been seen in a metallic form till Sir Humphrey Davy procured it from some oxide discovered by Hissinger and Berzelius in 1804. Its scarcity will prevent its being applied to any useful purpose.
The metals are simple substances, distinguishable from all other bodies by their lustre, great specific gravity, perfect opacity, and superior power of conducting electricity. They are the great agents by which we are enabled to explore the bowels of the earth, and examine the recesses of nature. Their uses are so multiplied, that they are become of prime importance in every occupation of life.
The reason why one metal possesses such opposite and specific differences from those of another, is not to be attributed to chance, but must certainly be the effect of consummate wisdom and contrivance. These metals differ so much from each other in their degrees of hardness, lustre, color, elasticity, fusibility, weight, malleability, ductility, and tenacity, that the Author of nature appears to have had in view all the necessities of man coming within the range of their operation.[112]