Copper ring

“ Next to gold, silver, and platinum, copper is the most malleable and ductile of metals; it may be drawn into wires as fine as hair, or beaten into leaves as thin as those of silver. The rust of copper is very poisonous. Copper, mixed with a certain quantity of tin, forms bell-metal. With a smaller proportion, it forms bronze, a substance used in sculpture for casting figures and statues. It is an abundant metal, and is found in various parts of the world. Native oxides of copper are found in Cornwall, Siberia, and in North and South America. ”

“ When the refining has been properly done, and neither too much nor too little oxygen is present, the copper is in the condition of “tough pitch,” and is in a fit state to be worked.
Copper is said to be “tough pitch” when it requires frequent bending to break it, and when, after it is broken, the color is pale red, the fracture has a silky luster, and is fibrous like a tuft of silk. On hammering a piece to a thin plate it should show no cracks at the edge. At tough pitch copper offers the highest degree of malleability and ductility of which a given specimen is capable. ”

“ Copper is used in small quantities as an alloy for gold and silver both in coinage and in plate, to give the requisite degree of hardness. Gold used for coins, or what is called standard gold, is formed of eleven parts of pure gold and one part of copper. Being a better conductor of electricity than any other metal, it is largely employed in the formation [299] of telegraphic wires; and, as it is not hard enough to strike fire with flint or grit, it is used in gunpowder mills and magazines instead of iron. ”

“ The alloys of copper and tin may be decomposed by dissolving them in an acid, the muriatic for instance, and immersing a sheet of iron, which will precipitate the copper. The tin may then be separated by immersing a plate of lead, or zinc, by either of which metals, it will be precipitated.
Bronze, being a mixed metal, in which the copper forms the principal ingredient, is sometimes used in fire-works, in lieu of copper or brass; for its effects are similar. By the combustion of bronze filings, we have an oxide of copper and an oxide of tin. ”

“ Copper, if not completely removed, has a very marked effect on the appearance of the button: the metal is spread out, damping, as it were, and firmly adhering to the cupel, which latter in the neighbourhood of the metal is almost black with oxide of copper. Sometimes the silver button is globular, or even more sharply rounded on its under than on its upper surface; it is said that this is due to the presence of lead. Gold may be present even to the extent of 50 per cent. ”

“ It is then, in his opinion, the solution of the metal—the wear of its surface, by keeping it smooth, which prevents the adhesion of foreign matter. Whenever the copper is unequally worn, deposits will, without doubt, rest in the rough parts, or depressions in the metal, and afford a soil or bed in which sea-weeds can fix their roots, and to which zoophytes and shell-fish can adhere; but there is another cause of foulness on the protected sheathing, arising from the deposit of earthy matter upon the copper, in consequence of its electro-negative condition. ”

“ Now, we know that copper is found in the mines in a state of such comparative purity as to require very little smelting for the purpose of being brought into a state fit for use, while, on the other hand, iron in its rough state looks more like a stone than a metal, and, moreover, before it can be worked at all, must be subjected to a difficult process of smelting by means of a very powerful fire. If we look at the question only on this side, we are forced to conclude, that copper must have been found and employed before iron. ”

“ If the copper be varnished, or covered with a coat of wax, they will not deposit themselves or go together at all; but where they find the clean surface of the metal, they at once not only settle, but fix and adjust themselves in their proper forms, building up as it were a metal structure, not eccentric or uneven, but forming a correct plate of new metal, so pure, so hard, and so free from defect or extraneous matter, that engravers prefer copper plates thus formed to any other for working upon. ”

“ Ordinary commercial copper is somewhat porous and has a specific gravity ranging from 8.2 to 8.5. It takes a brilliant polish, is in a high degree malleable and ductile, and in tenacity it only falls short of iron, exceeding in that quality both silver and gold. ”

“ As copper does not, like iron, strike fire by collision, it has on this, as well as on some other accounts, been substituted for iron in the machinery which is employed in gunpowder mills. It is also made into water pipes, and sometimes into sash frames. Under the hammer it is capable of being beaten into thin leaves like gold. Copper wire is much employed by bell-hangers and other artisans. The filings of this metal are used for giving a green colour to some kinds of artificial fire-works. ”

“ The demand for particularly pure metal in electrical and conductivity work therefore usually necessitates a further purification of the converter-copper (unless it be an exceptionally pure brand) and the production of metal specially free from the injurious constituents which persist to a small but sometimes very appreciable extent in the metal under the ordinary oxidising conditions. The presence of silver and gold in the copper may afford in many instances sufficiently good reason for a separating process independently of the market for the pure copper itself. ”

“ The ore is afterwards melted several times to separate the other impurities, which, when fused, float like scum on the surface of the liquid metal, and are then easily removed.
Copper has a peculiar reddish colour, and will bear a brilliant polish; its smell and taste are both disagreeable. It is one of the most malleable of metals, and can be so readily worked by the hammer that it is beaten out into thin leaves, which, under the name of “Dutch metal,” are employed in ornamenting toys, &c. ”

“ This accident, called the rising of the copper, hinders it from being laminated, and requires it to be exposed to a fresh refining process, when lead must be added to dissolve the oxide of copper. This is the only occasion upon which the addition of lead is proper in refining copper. When the metal to be refined is mixed with others, particularly with tin, as in extracting copper from old bells, then very wide furnaces must be employed, to expose the metallic bath upon a great surface, and in a thin stratum, to the oxidizing action of the air. ”

“ It is remarkable, that copper, in the dry state, has a very strong action upon iron; and that the tools employed in stirring the liquid metal become very glistening, like those used in a farrier’s forge. The iron of the tools consumes more rapidly at that time, than when the copper has acquired its malleable state. The metal requires, also, when dry, more time to become solid, or to cool, than when it is refined; a circumstance depending, probably, upon the difference in fusibility of the copper in the two states, and which seems to indicate, as in the case of iron, the presence of oxygen. ”

“ Copper is preferable to iron as the material for their construction, being less liable to destruction by rust, or by fusion, and possessing also a greater conducting power. The size of the rods should be from half an inch to an inch in diameter, and the point should be gilt, or made of platina, that it may be more effectually preserved from corrosion. ”

“ In speculum metal there are 2 to 21⁄2 parts of copper to 1 of tin. Statuary bronze may contain from 80 to 90% of copper, the residue being tin, or tin with zinc and lead in various proportions. The bronze used for the British and French copper coinage consists of 95% copper, 4% tin and 1% zinc. Many copper-tin alloys employed for machinery-bearings contain a small proportion of zinc, which gives increased hardness. "Anti-friction metals," also used in bearings, are copper-tin alloys in which the amount of copper is small and there is antimony in addition. ”

“ A coronal, consisting of a copper band, with stout copper points, each a foot long, at intervals of two or three feet on its circumference, is recommended for the chimneys of factories. Copper is preferred to iron as the material for rods, chiefly because it is less liable to be injured and rendered inefficient by rust. ”

“ When lead is the only easily oxidisable metal present, the stained portion of cupel is yellow when cold. A greenish tint may be due to small quantities of copper or, perhaps, nickel, cobalt, or platinum. Larger quantities of copper give a greenish grey or almost black colour. A dark green and corroded cupel may be due to iron. Rings of pale-coloured scoria may be due to tin, zinc, antimony, or arsenic. When the cupel shows signs of the presence of these metals in objectionable quantity, it is well to repeat the assay and scorify so as to remove them before cupellation. ”

“ A white crystaline stone is also found to contain a great quantity of yellow copper. The lodes of copper ore generally lie deeper than those of tin, and its ores are mostly of the pyritous and sulphurated kinds, with more or less arsenic. “The lodes, both of tin and copper, appear most frequently to have granite for their country, and to make an angle from 60° to 76° with the horizon.” The matrices of copper ore are very numerous. Among the blue ores, there is one of an extremely fine blue earth. ”

“ Copper exists in considerable quantities in the neighborhood of Dondon and Jacmel, and in the Cibao; silver is found near San Domingo, and in various places in the Cibao, together with cinnabar, cobalt, bismuth, zinc, antimony, and lead in the Cibao, near Dondon and Azua, blue cobalt that serves for painting on porcelain, the gray, black specular nickel, etc.; native iron near the Bay of Samana, in the Mornes-du-Cap, and at Haut-and Bas-Moustique; other forms of that metal abound in numerous places, crystallized, spathic, micaceous, etc. ”

“ Copper ores are, however, very rarely found in a pure state, and the small impurities of antimony, arsenic, &c., combine in the smelting with the copper, and lend a hardness and ductibility which would enable it to be cast in closed moulds. ”

“ He pointed out several new forms of crystals in the slags from his blast furnaces, and he also beautifully illustrated the theory of the formation of native copper from the vaporized chloride of copper, while working the Atacamite of Peru.
"The most important of his labors were of an eminently practical nature, such as discovering the best and most economical methods of mixing the various copper ores of commerce, so as to make one ore flux another, and thus to obtain the largest yield of metal at the least expense. ”

“ In separating copper from silver or gold, advantage is taken of this fact; for, although we cannot cupel an alloy of copper and silver, it is easy to cupel an alloy of copper, silver and lead. If, however, the lead is not present in sufficient quantity, the whole of the copper will not be removed, and the button of silver, still retaining copper, will be found embedded in a coating of black oxide of copper. Copper oxidises less easily than lead does ”

“ Copper, however, has been at some time noticed to fall from the sky, and this is not very unlike iron; and in fact cloud-born iron of this sort, or copper, are seen to be imperfectly metallick, incapable of being cast in any way, or wrought with facility. For the earth hath of her store plenty of iron in her highlands, and the globe contains the ferric and magnetick element in rich abundance. The exhalations forcibly derived from such material may well become concreted in the upper air by the help of more powerful causes, and hence some monstrous progeny of iron be begotten. ”

“ Money is made of copper, too.
Tut. It is; for it takes an impression in coining very well, and its value is a proper proportion below silver, for a price for the cheapest commodities. In some poor countries they have little other than copper coin. Another great use of copper is as an ingredient in mixed metals, such as bell-metal, cannon-metal, and particularly brass.
Har. But brass is yellow.
Tut. True; it is converted to that colour by means of another metallic substance, named zinc or spelter, the natural colour of which is white. A kind of brown stone called calamine is an ore of zinc. ”

“ In fact we know for certain that such an independent Copper Age was developed not only in the region of the Great Lakes of North America, but also amongst the Bantu peoples of Katanga and other parts of Central Africa. Copper is not an alloy like bronze, but a [Pg 24] soft, easily-worked metal occurring in large quantities and in a tolerably pure state near the surface in many parts of the world. ”

“ Such copper being particularly suited for various engineering and mechanical uses, the arsenic being sometimes even specified for and purposely added—as in fire-box plates and stay bolts, though it is never employed for conductivity work or for the manufacture of alloys if any considerable proportion be present—the metal found a ready market when brought to pitch. ”

“ Though copper is such a tough substance, and though tin is also tough, yet when melted together to make speculum metal, as this alloy is called, they produce an exceedingly hard and brittle material. When we remember that we could never break a copper penny piece by throwing it down on the flags, it may seem strange that the “speculum metal” should be so exceedingly brittle. A piece the size of a penny would be more brittle than a bit of glass of the same dimensions, and when the speculum is cast, unless it is cooled very carefully, it will fly into pieces. ”