Page:Encyclopædia Britannica, Ninth Edition, v. 24.djvu/653

Rh W I E W I S 615 must possess a certain amount of tenacity, the quality on which the utility of wire principally depends. The metals suitable for wire, possessing almost equal ductility, are platinum, silver, iron, copper, and gold; and it is only from these and certain of their alloys with other metals, principally brass and bronze, that wire is prepared. By careful treatment wire of excessive tenuity can be pro duced. Dr Wollaston first succeeded in drawing a platinum wire ^crocTo i nca * n diameter by encasing a fine platinum wire within silver to ten times its diameter. The cored wire he then reduced to ^Vrr i ncn &amp;gt; and by dissolving away the silver coating the platinum wire -j^-JoT) ^ nen thick only remained. By continued treatment in this way wires of platinum used for spider-lines of telescopes are now obtained of such extreme tenuity that a mile length of the wire weighs not more than a grain ; and it is said that platinum wire has been made which measures not more than -j^Vc 7 mm -&amp;gt; part of an inch. Diameter. Gold I -01(12 inches. I liitinum ; -01(51 Silver Copper Iron Copper Urass Steel Phosphor Bnmze 0157 0177 0109 0605 OIUO OGOO OG.30 to less than the fifty-thousandth The accompanying table shows the com parative tenacity of the wire of metals and metallic alloys. Wire was originally made by beating the metal out into plates, which were then cut into continuous strips, and afterwards rounded by beating. The art of wire-drawing does not appear to have been known till the 14th century, and it was not introduced into England before the second half of the 17th century. Wire is usually drawn of cylindrical form ; but it may be made of any desired section by varying the outline of the holes in the draw-plate through which it is passed in the process of manufacture. The draw-plate is a disk of hard steel pierced with a series of holes corresponding in aperture with the size and section of the wire to be made. The holes are funnel-shaped, being widest at the side where the metal enters, and tapering to their small diameter at the face where the wire is drawn away. The excessive friction, which is partly relieved by lubricants, causes a rapid enlargement of the holes ; and where great uniformity of size is required, as in the case of fine gold, silver, and platinum wire, perforated rubies or similar hard stones are fitted in the draw-plate. The draw-plate is mounted in the draw-bench, which is provided with a reel on which the wire is wound, and in drawing down to smaller dimensions it passes through successive smaller holes in the draw-plate one at a time and is wound on another reel or frame on the bench. During the drawing the wire requires to be annealed more or less frequently according to the nature of the metal under treatment. The ductility of the metal and the diameter of the wire operated on determine the rapidity with which the wire can be drawn : iron and brass travel at rates varying from 12 to 45 inches per second, while gold and silver wires of fine section may be drawn through at 60 to 70 inches per second. Stout iron wire down to a section of ^ inch or thereby is made by rolling bars of fine fibrous metal in a rolling mill, in the same way as nail rods, small bars, and angles are rolled. The thinner wires are drawn from these stout wires by the ordinary process of draw ing. Iron requires repeated annealing in the process of attenuation, and to preserve it from oxidation it is treated with a scour-bath, consisting of dilute sulphuric acid and a proportion of sulphate of copper. The minute film of copper thus deposited on the wire not only prevents oxidation, but also favours the drawing by lessening the friction in passing through the draw-plate. Much of the iron wire which is to be used in exposed situations is further protected from oxidation by a covering of zinc in the so-called galvanizing process. In commerce the sizes of wire are estimated by certain more or less recognized standard wire gauges. The most commonly quoted is the Birmingham wire gauge. It gives forty measurements, which bear no definite relation to each other, ranging from the largest No. 0000 = 454 inch to No. 36 = 004 inch. Sir Joseph Whitworth in 1857 proposed a standard wire gauge which is coming to be generally recognized. His measurements range from half an inch to one-thousandth of an inch by regular gradations of onc- thousandth. Beginning at the smallest, No. 1 is 001 inch, 2= 002 inch, 10 = 010 inch, and so on, larger breaks being made in the scale as the size increases, but the number and ratio continuing the same till it ends at No. 500 = 500 inch. In America a standard wire gauge, proposed in 1864 by Messrs Brown and Sharpe, of Providence, II. I., is now extensively recognized. In it the grada tions are uniform, increasing in geometric ratio, so that the size of each successive number is found by multiplying the preceding by 1-123. The standard is calculated from wire No. 36, which in the American gauge represents a diameter of 005, while in the Birming ham gauge No. 36 is equal to 004 inch. It must be obvious that the uses of wire are multifarious and diverse beyond all enumeration. It forms the raw material of important manufactures, such as the wire-net industry, wire-cloth making, and wire-rope spinning, in which it occupies a place ana- Logons to a textile fibre. Wire-cloth of all degrees of strength and fineness of mesh is used for sifting and screening machinery, for draining paper pulp, for window screens, and for many other purposes. Vast quantities of copper and iron wire are employed for telegraph and telephone wires and cables, and as conductors in electric light ing. It is in no less demand for fencing, and much is consumed in the construction of suspension bridges, and cages, &c. In the manufacture of stringed musical instruments and philosophical apparatus wire is again largely used. Among its other sources of consumption it is sufficient to mention pin and hair-pin making, the needle and fish-hook industries, nail, peg, and rivet making, and carding machinery ; but indeed there are few industries into which wire does not more or less enter. WIRE ROPE. See ROPE, vol. xx. p. 846. WISBECH, or WISBEACH, a municipal borough, market- town, and seaport of Cambridge, England, in the Isle of Ely, is situated on the river Nene, on the Wisbech Canal, by which there is connexion by the Ouse with Hertford, and on branches of the Great Eastern and Midland Rail ways, 40 miles north of Cambridge, 21 east-north-east of Peterborough, and about 90 from London. It possesses a spacious market-place, a handsome crescent, and several good streets. There is a public park, 18 acres in extent. The greater part of the town is situated on the south side the river, which is crossed by an iron bridge. The church of St Peter and St Paul is very singularly constructed, having two parallel naves, two aisles, and two chancels, with a large square tower at the west end, originally dating from the 12th century, but almost entirely recon structed about the close of the 15th century. The church contains some semicircular Saxon arches as well as some traces of Early Norman. Among the other public build ings are the corn exchange (re-erected 1811), the public hall, the custom-house, the new cattle market, the work ing men s club and institute, and the museum and literary institute, with a library of 12,000 volumes and a fine collection of Roman remains and other antiquities. Be sides the Cambridgeshire Hospital (1873) and the twelve corporation almshouses there are a large number of other charities. A grammar-school was established in the middle of the 16th century, and provision vas made in the charter of Edward VI. for its continuance. A Gothic monument was erected here to Thomas Clarkson, the anti-slavery orator, in 1881. Vessels of 500 tons burden can enter the port, and extensive wharfage has been erected at a cost of 60,000. The number of vessels that entered the port in 1886 was 294, of 50,721 tons, and the number that cleared 286, of 50,812 tons. The chief imports are corn, potatoes, wool, timber, and iron, and the exports agricul tural produce and salt. In the neighbourhood immense quantities of fruit are grown, including apples, pears, plums, gooseberries, and strawberries. Potatoes, asparagus, and other vegetables are also largely grown for the London market. The town possesses agricultural implement works, coach-building works, breweries, ropeworks, planing and sawing mills, and corn and oil-cake mills, many of them driven by water, and others by steam. The town is divided into two wards, and is governed by a mayor, six alder men, and eighteen councillors. It has a separate commis sion of the peace. The corporation act as the urban sanitary authority. Water is obtained from chalk springs near Norfolk. The population of the municipal borough in 1871 was 9362 and in 1881 it was 9249. Wisbech was most probably a fort of the Romans, who it is sup posed constructed the river banks in the neighbourhood. It takes its name from the river Ouse (Wyse). It is first noticed in 604, iu a charter of Wulfhere, sou of Penda. In the early part of the