COPPER

COPPER (including its alloy brass) and iron are the first metals named in the most ancient authentic history of the world, as having been made use of by man. Tubalcain was "an instructor of every artificer in brass and iron." The words ἄρ and χάλκος (usually translated brass) of the ancient Romans and Greeks were used indifferently to apply to the pure metal copper (as when they spoke of their money) and to its alloys with other metals, as when they spoke of their brazen statues, or of their defensive and offensive armour, in which case the copper was alloyed with tin. The enormous statue of the Sun, known by the name of the Colossus of Rhodes, was composed entirely of bronze (see COLOSSUS); and many others are mentioned, which prove that the ancients were at least as well acquainted with the difficult art of working in brass as we are at the present day.

In a pure state, copper is a very brilliant metal, and susceptible of a high polish. It is of a fine red colour, differing in this respect from every other metal except titanium. Its specific gravity varies, according to its density, from 8.584 to 8.9. According to Brard, the cubic foot of melted copper weighs.....545 lb. Of native metal.....600 lb. Of copper medals.....620 lb. In a native state, it is not an uncommon mineral. It occurs in arborescent groups, very beautifully crystallized, in Siberia, imbedded in limestone, and in very considerable masses. In the cabinet of Ajuda, near Lisbon, a mass of native copper is said to be preserved, of the enormous weight of 2617 pounds (Brard). In Cornwall it occurs in many of the mines, and also in the island of Anglesea; and in the island of Nalsoc, one of the Feroe group, it occurs very beautifully crystallized, along with zeolite, imbedded in amygdaloidal trap.

Metallic copper is used for culinary vessels in many parts of Europe; but for this purpose the inner surface of the vessel should be tinned. Large vessels for distilling, brewing, dyeing, and the like processes, are made of copper. The making of these vessels constitutes the ordinary business of the coppersmith.

Copper rolled into sheets is employed for covering the wooden work of the roofs of churches and large edifices in Germany, Sweden, and other countries. It is a costly covering, and does not possess any commensurate advantage over lead.

Copper. A modern, and now a very extensive use of sheet-copper, is for the sheathing of ships. That part of the hull of a ship that is in the water is covered with sheet-copper. This covering preserves the wood from the attacks of the teredo, and thereby gives the ship the advantage of passing more rapidly through the water, as the copper bottom remains always smooth; for sea-weed and shells will not take root and attach themselves to copper, as they do to bare planks, owing to the galvanic effect produced by the action of sea water. As this action, however, produces a rapid decay of copper, it was proposed by Sir Humphry Davy to neutralize it by applying metallic protectors—an object which he accomplished; but as this also deprived the copper of the effect it was intended to produce, and allowed the molluscous tribes to attach themselves, the protecting process was abandoned.

Its malleability and ductility are very considerable. A wire of 0.078 of an inch diameter will support 302 pounds avoirdupois.

Copper bolts are used for fastening the planks and timbers of ships. This is a great improvement in ship-building. A copper-fastened ship or boat is preferable to one with iron fastenings, because the copper bolts remain unaltered by rust, and endure longer than the wood which they hold together, particularly when used in the state of alloy, which preserves it from waste by neutralizing the galvanic action.

For the frames of delicate dipping needles and magnetic compasses, copper is employed; as it has been found that the brass generally used in philosophical instruments sometimes contains iron, which of course might affect the magnetic needle.

Copper is drawn into wire, used for the communication with the bells in houses, and for other purposes.

Small pipes for conveying coal-gas from the level of the street to the aperture by which the gas issues, were formerly made of copper or of brass, till superseded by tin. These pipes were fitted on an iron cylindrical mandril, and a cylindrical ring drawn over the outside. By this means copper and brass tubes are drawn out. The brass tubes for telescopes are drawn out in the same manner.

Copper may be plated; that is, its surface may be covered with a layer of silver, by rubbing the surface with a mixture of nitrate of silver, muriate of soda, and acidulous tartrate of potass (cream of tartar). But the method practised at Birmingham is the most permanent and effectual. A plate of copper, with a plate of silver applied to it, and borax placed in the interstice, is heated to a particular degree, which it requires the skill of the workman to know; a degree of heat, in short, near that at which copper and silver melt. The two metals thus heated, and in contact, are then taken out of the furnace and passed through rollers. There is a fusion and combination of the adjacent surfaces; and their adhesion is perfected by the pressure of the rollers. Copper thus plated is manufactured at Birmingham into candlesticks, teapots, buttons, buckles, and a variety of other articles.

Standard silver coins contain a small proportion of copper, for the purpose of giving them hardness. This proportion is regulated by government in the several countries of Europe, and varies in different states. The combination of gold and copper in various proportions is used for making rings and other trinkets.

Copper is gilded by applying on its surface an amalgam of gold with mercury. Bronze ornaments are gilded in the same way.

Copper united with zinc forms brass: when alloyed with tin it forms bronze. This combination is hard and brittle if the proportion of tin be great; but when the proportion of tin is small, the bronze is soft, and possesses tenacity so as not to be easily broken. The ancients employed hard

bronze, containing much tin, in making sword blades, spear heads, hatchets, and cutting instruments. Bronze cramps are found in ancient buildings in Egypt. Statues and bas-reliefs, culinary vessels, and a variety of other articles of soft bronze, are to be seen in different collections of antiquities. In modern times soft bronze is used for casting canon and statues.

Copper melted with a large proportion of tin constitutes bell-metal, which is hard and brittle. The metal of which the Chinese gongs are made is composed of the same ingredients; and it has the property of being in some degree malleable at a certain stage of its cooling, for their gongs are covered with marks of the hammer.

The most common ore of copper, from which the chief supplies of that metal are derived, is the yellow copper ore, or copper pyrites, essentially a combination of copper with sulphur and iron. There are, however, numerous other ores of copper in which the metal is in combination with oxygen, carbonic acid, various other metals, &c.

Copper in its varied artificial combinations, as in that of verdigris (acetate of copper), blue vitriol (sulphate of copper), Scheel's green (arsenite of copper), verditer (carbonate of copper), &c., is largely used in the arts of dyeing, painting, enamelling, glass and porcelain colouring, &c.

The salts of copper are poisonous; and from the facility with which copper utensils become oxidated, their use should be as prescribed as possible. One or two of the salts of copper are occasionally used in medicine; and the sulphate of copper has been found to be one of the most efficacious emetics in croup, checking the disease and preventing the effusion of the fibrinous matter into the trachea. This salt is also used as a lotion in the treatment of ulcers, &c.

Quantities of Copper Ore imported into the United Kingdom for home consumption in 1851, with the Duties charged thereon.

In 1853 the duty on copper ores and on wrought copper was repealed.