Wire

a thread, or small rod of metal. The making of wire depends on a property of metals known as ductility. In production, a piece of metal is drawn through a series of holes in a hardened steel plate. A rod or bar once formed is drawn through a succession of holes each smaller in diameter than its predecessor. In this way, even the finest wires may be made. Gold, silver, platinum, iron, copper, zinc, tin, lead, and nickel may be made into wires. Platinum has been drawn into wire 0.000165 inch in diameter, so fine as to be scarcely visible to the unaided eye. Fine gold wire, known as gold thread, was much used by the ancients for purposes of embroidery. It was made by a process of hammering and dividing. The earliest wire making by drawing rods through holes without the aid of the hammer, was first practiced, so far as known, at Augsburg and Nuremberg about the middle of the fourteenth century.

Wire is known in the trade by number, according to its diameter. A number twelve piano wire is 0.029 inch in diameter. A well made steel wire has wonderful strength. The number twelve wire mentioned is able to support a weight of 225 pounds, equivalent to 1,000 tons per square inch of section.

Wire is now applied to many uses. In the United States alone about half a million tons are converted annually into wire nails. Wire is used in the construction of cables and of ropes requiring great strength where flexibility is not necessary. Suspension bridges are hung on wire cables. An immense amount of steel, copper, and aluminum wire is used to transmit electricity. Since the Civil War, wire, both barbed and smooth, has taken the place very largely of wooden fencing.

There are in the United States alone 597 wire-making establishments, having an annual output valued at nearly $20,000,000. Stated in terms of weight, the annual output of the American mills (1905) is not far from 2,000,000 tons a year. It is stated that out of every ten pounds of steel produced one pound is made into wire.