Page:The American Cyclopædia (1879) Volume XVI.djvu/701

WIRE 677 should be made successively smaller by almost imperceptible gradations, so that the reduction of the wire and the effort required shall be at the successive drawings as nearly uniform as possible. Whether wire is drawn by ma- chinery or by hand, after a few drawings, and less in number as its size is smaller, it so far becomes brittle under the process as to be in danger of snapping off, or at least as to impair its quality and strength ; and it requires to be annealed. (See ANNEALING.) The wire is then scoured or washed to free it from oxide ; im- mersion for a time in starch water or in stale beer grounds is found to favor this result. At a wire manufactory some years since, some in- gots of brass were heated and quenched in the slightly acid liquor employed for cleaning the annealed wire, as a ready means of warming the liquor ; this wire was found to pass with unusual ease through the draw-plate; and an examination showed that the acidulated liquor had deposited over the wire (by galvanic ac- tion) a delicate film of copper, which appeared then to play the part of lubricant to the iron. This has led to the employment ever since in that factory of a weak solution of a cop- per salt in the cleaning liquor, the copper film being wholly removed in connection with the last annealing. With most descriptions of wire, grease also is commonly and freely used, and with the finer sizes wax, for lubrication. Mr. Brockedon in 1819 patented the use in fine draw-plates of the hardest precious stones. With a plate having a hole pierced through a ruby, of 0-0033 in. in diameter, a silver wire 170 m. long has been drawn so nearly uniform that neither the micrometer nor the weighing of equal lengths at the two ends showed any difference in the size. In 1813 Dr. Wollaston communicated to the royal society a method devised by him for preparing wires of extreme tenuity, for use in place of the " spider lines " in the telescope. He drilled holes lengthwise through small rods of silver, cast into these cores of gold, drew the compound bars, and then removed the silver by an acid. Subse- quently he drew platinum wire, say to y^ inch diameter, and cast about this a cylinder of sil- ver, such that the platinum should be ^V the diameter of the compound rod ; this rod, in. in diameter, is then drawn to a wire so fine that, the two metals (as in case of the gold and silver above) perfectly maintaining their rela- tive diameters throughout the process, the re- moval of the silver by nitric acid leaves a pla- tinum wire of far less size than could be attained by drawing the metal singly, which has been brought, it is said, to a thickness of only ^svhnr of an inch. Of such wire, a mile's length would weigh but a grain, and 150 filaments in close contact would barely equal the size of an ordinary filament of raw silk. Actual gold wire being in use for a few purposes only, among them that of making filigree work, that which is commonly known as "gold wire" is really silver gilt ; and the mode of making this quite as strikingly exemplifies the extreme ductility of the precious metals. A silver rod an inch m diameter is covered with leaf gold, and by drawing and annealing this rod is then reduced to the finest wire required ; and though in the outset but 100 to 140 grains of gold are thus allowed to a pound of silver, the wire produced is still completely coated. Such wire is wound upon thread to form gold thread, the economy . as well as beauty of the product being increased by previously flattening the wire between pol- ished steel rollers. Brass wire also is made so fine, even by the ordinary processes, that gauze may be woven from it which shall have 67,000 meshes to the square inch. Wire is applied to a great variety of uses, among which is that of the manufacture of wire gauze or cloth. Beck- mann refers to some very intricate and curious old specimens of wire network. The plainer sorts of wire gauze or network are woven on looms differing but little from those for cloth. Those of large wire and open meshes are em- ployed for fences, large cages or buildings of wire for birds or small animals, and for coarse riddles or sieves, &c. ; the finer sorts are put to use in the construction of sieves, lanterns, flour- dressing machines, paper-making machi- nery, screens for windows, safety lamps, &c. By pressing sheets of wire gauze in moulds, the shape of which they retain, and finishing off their edges with hoops or rings, these are formed into dish covers, baskets, &c. The wire in bird cages, fenders, and other like ar- ticles is often specially plaited or woven in forming them, so that, as in the case of the making of baskets, they admit of a great vari- ety of construction and ornamentation. Knit- ting and sewing needles and pins are at first cut from wire expressly prepared for such man- ufacture, and some of the finest sorts of steel wire are consumed in making the hair springs of timepieces. A very important use of steel wire is its application in the way of the so-called "strings" of pianos. Spangles, or paillettes, which are small flat disks of metal with an opening in the centre, and used for ornament- ing garments, are formed of wire, by twisting this spirally round a rod, cutting so as to ob- tain as many single coils or rings, and then flat- tening these with a hammer upon a smooth an- vil. Gold and silver wires are much used in the production of filigree work. (See FILIGREE.) Wire is also used in making " wire concrete." This is done by stretching on a metal framework a system of wires or wire cordage, and enclosing it in concrete. Doors and shelves can be formed in this way, and it is proposed to utilize the in- vention in the construction of sea walls. For the making of wire into wire rope, and in refer- ence to the comparative strength and some of the uses of such rope, see BBIDGE, and ROPE; ar.d for the use of wire in telegraph lines, see TELE- GRAPH. Brass wire is used in large quantities for the manufacture of pins and of hooks and eyes; also for binding the handles of brooms. Copper and sometimes iron wire is used for