Page:EB1911 - Volume 23.djvu/411

 and asphalt are more slippery when wet, and that therefore watering should be obviated as far as possible by thorough cleansing. Hydrostatic vans, by improvements in the distributing pipes and regulating valves, water a wide track uniformly with an amount of water which can be regulated at pleasure. Where hydrants exist in connexion with a water supply at high pressure, street watering can be effected by a movable hose and jet, a method much more effective in cleansing the surface, but using a much larger quantity of water. Another method which has been tried, but not much used, 1S to lay rforated pipes at the back of the kerb on each side of the road, fiibm which jets are thrown upon the surface. The first cost is considerable, and the openings for the jets are liable to choke and get out of order. Deliquescent salts have been used for street watering, by which the surface is kept moist, but at the expense of the moisture in the air. Sea water has the same effect in a less degree.

Cleansing.—The principal streets of a town are generally cleansed daily, either by hand-sweeping and hand-scraping or by machines. Sir Joseph Whitw0rth's machine consists of a series of revolving brooms on an endless chain, whereby the mud or dust 15 swept up an incline into the cart. A less costly and cumbersome machine consists of a revolving brush mounted obliquely, which sweeps a track 6 ft. wide and leaves the dust or mud on one side to be gathered up by hand. A horse scraping-machine which delivers the mud at the side is also used, the blades of the scrapers being mounted obliquely and covering a width of 6 ft. For general use, more especially in the country, scraping-machines, worked by a man from side to side of the road, and scraping a width of about 4 ft., are more convenient.

All street surfaces suffer from the constant breaking up and disturbance to which they are subjected for the purpose of laying and repairing gas and water pipes. Subways, either under the middle of the road or near the kerbs, in which the pipes may be laid and be always accessible, have often been advocated, and in a few instances pave been constructed; but they have not hitherto found general favour.

Footways.—Gravel is the most suitable material for country or suburban footways; it should be bottomed with a coarser material, well drained and should be laid with a roller. An inclination towards the kerb of about half an inch in a foot may be given, or the surface may be rounded, to throw off the wet. Where greater cleanliness is desirable and the traliic is not too great a coal-tar concrete similar to that already described, but of smaller materials, makes a good and economical footway. The coating should be 2 or 3 in. thick, composed of two or three layers each well rolled, the lower layer of materials of about 1 in. gauge, and the upper of a half or a quarter of an inch gauge, with Derbyshire spar or fine granite Chippings over all. Concrete footways require to be carefully made and must be allowed to set thoroughly before they are used. Concrete has a tendency to crack from contraction, especially when in a thin layer, and it is better to lay a footway in sections, with joints at intervals of about 2 yds. Concrete slabs, especially when silica ted and constituting artificial stone, make an excellent footway. The material is composed of crushed granite, gravel or other suitable material, mixed with Portland cement and cast in moulds, and when set saturated with silicate of soda. This paving has proved more durable than York stone flagging, but it is more slippery, especially when made with granite. York stone makes a good and pleasant foot pavement, but is somewhat expensive considering its durability; it is apt to wear unevenly and to scale off when the stone is not of the best quality. It should not be laid of a less thickness than 2 in.; 2 or 3 in. are more usual. The flags should be square jointed, not under-cut at the edges, and should be well bedded and jointed with mortar. Caithness flag is much more durable than York stone and wears more evenly; it is impervious to wet and dries quickly by evaporation. The edges are sawn, and the hardness of the stone renders it difficult to cut it to irregular shapes or to fit openings. Staffordshire blue bricks and bricks made of scoria from iron furnaces are both very durable, though somewhat brittle. Asphalt either laid as mastic or compressed is extensively used for footways; the former is considered inferior in durability to York stone and the latter superior to it. Asphalt should not be laid less than three-fourths of an inch thick on 4 in. of cement concrete, and 1 in. of asphalt is desirable where there is great traffic.

Footways in a street must be retained by a kerbing of granite, York stone, Purbeck or other stone sufficiently strong to stand the blows from wheels to which it is subjected. It should be at least 4 in. wide and 9 deep and in lengths of not less than 3 ft. A granite kerb is usually about 12 by 6 in., either placed on edge or laid on the flat. When set on edge a kerb is generally bedded on gravel with a mall; when laid on the fiat a concrete bed is desirable.

In a macadamized street pitched or paved water channels are required to prevent the wash of the surface water from undermining the kerb. The pitching consists of cubical blocks of hard stone about 4 in. deep, bedded on sand or mortar, or preferably on a bed of concrete. A paved channel consists of flat stones about 1 ft. wide inclining slightly towards the kerb. Moulded bricks and artificial stone are also used both for side channelling and for kerbing. Such an inclination must be given to the channel as will bring the surface water to gullies placed at proper intervals, and the level of the kerbing and consequently of the footway will depend to some extent on the surface drainage as well as on the levels of adjacent houses. To lay out a street satisfactorily the longitudinal and transverse sections must be considered in relation to these matters as well as to the levels of intersecting streets.

ROAN (O. Fr. rouan, rouen; Ital. roano, rovano; perhaps connected with rufus, red), a word applied to a variety of colour in an animal's coat, especially that of a horse, where there is a mixture of grey or white hair with the prevailing tint of bay, chestnut or sorrel. A sorrel when thus modified is either a strawberry-roan or a cream-roan. The term is also used of a soft, flexible kind of leather made of sheepskin, used in bookbinding as a substitute for or in imitation of morocco; but in this sense the origin is doubtful.

ROANNE, a town of east-central France, capital of an arrondissement in the department of Loire, on the left bank of the Loire, 54 m. N.W. of Lyons on the Paris-Lyons railway to Moulins. Pop. (1906) 33,981. The chief buildings are a modern town hall and the church of St Étienne (1835–1843), built in the Flamboyant Gothic style. The lycée occupies the buildings of the old college dating from the early 17th century. A line bridge of seven arches connects Roanne with the industrial suburb of Le Côteau on the right bank of the river. The town is the seat of a sub-prefect, of tribunals of first instance and of commerce, of a chamber of commerce and a board of trade-arbitration, and has lycées for both sexes. Cotton goods form the staple manufacture, and cotton-spinning is also important. The making of knitted woollen articles gives employment to large numbers of women in the town and district. There are besides extensive engineering works, foundries, dye-works, tanneries, pottery and tile-works and other industrial establishments. As the centre of the Roannais coalfield, Roanne has trade in coal and coke. It is also the terminus of the Roanne-Digoin Canal and the real starting point of the Loire navigation.

Roanne (Rodomna, or Roidomna) was an ancient city of the Segusiani and a station on the great Roman road from Lyons to the ocean. In 1447 the lordship of Roannais became the property of the celebrated banker Jacques Cœur, from whom it passed as the result of a law-suit to the family of Gouffier. In their favour the title was raised to the rank of marquis ate and in 1566 to the rank of duchy; it became extinct in the first half of the 18th century.

ROANOKE, a river of the South Atlantic Slope, U.S.A. With the Staunton, which rises in the Appalachian Valley in south-western Virginia, it constitutes one river, and, flowing in a general south-easterly direction, crosses the boundary between Virginia and North Carolina just above the Fall Line and discharges into Albemarle Sound. It is nearly 400 m. long, with a drainage area of 9237 sq. m. The United States government adopted a project in 1871 for clearing a channel with a minimum depth of 5 ft. at low water from its mouth to Weldon, a distance of 129 m., and in 1909, when the project was 80% completed, vessels drawing 4 ft. of water could ascend at low stages nearly to Weldon. The main river and its principal tributary, the Dan, are also navigable, for many miles above the Fall Line, by pole boats. In 1829 the Weldon Canal, 12 m. long, was opened to afford a passage around the falls, but it was abandoned in 1850.

ROANOKE, a city in (but administratively independent of) Roanoke county, Virginia, on the Roanoke river, about 55 m. W.S.W. of Lynchburg. Pop. (1890) 16,159; (1900) 21,495, of whom 5834 were negroes; (1910 census) 34,874. Roanoke is served by the Virginian railway, by the main line and the Shenandoah and the Winston-Salem divisions of the Norfolk & Western railway, and by electric railway to Vinton and to Salem. The city is about 900 ft. above sea-level and is surrounded by high hills; its picturesque situation and its nearness to famous mineral springs make it a health resort. On a mountain slope, about ½ m. from the city limits, is the Virginia College for Young Ladies; 7 m. north of the city, at what was