588 R A R O B cans- Cleansing. The principal streets of a town are generally cleansed g. daily, either by hand-sweeping and hand-scraping or by madiim-s. Whitworth's machine consists of a series of revolving brooms on an endless chain, whereby the mud or dust is 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 feet 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 feet. 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 feet, are more convenient All street surfaces suffer from the constant breaking ip and dis- turbance 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 have been constructed ; but they have not hitherto found general favour. >ot- Footivays. Gravel is the most suitable material for country or ivs. 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 traffic 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 inches thick, composed of two or three layers each well rolled, the lower layer of materials of about 1^ inches 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 care- fully 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 yards. Concrete slabs, especially when silicated 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 con- sidering 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 inches ; 2J or 3 inches 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 com- pressed 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 threg-fourths of an inch thick on 4 inches of cement concrete, and 1 inch of asphalt is desirable where there is great traffic. srbing. 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 inches wide and 9 deep and in lengths of not less than 3 feet. A granite kerb is usually about 12 by 6 inches, 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 flat a concrete bed is desirable. ie In a macadamized street pitched or paved water channels are annels. required, to prevent the wash of the surface water from under- mining the kerb. The pitching consists of cubical blocks of hard stone about 4 inches deep, bedded on sand or mortar, or preferably on a bed of concrete. A paved channel consists of flat stones about 1 foot 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. For fuller information on the subject see Sir Henry Parnell, A Treatise on. Roads; Thomas Codrington, The Maintenance of Macadamized Roads; Uebauve, Manuel de VInegnitur des Fonts et Chaussees; Annales des Fonts et Chaussees; Minutes of Proc. Inst. Civ. Eng., "Street Pavements," vol. Iviii. p. 1, and Wood Pavements," vol. Ixxviii. p. 240; Reports by W. Haywood, engineer to the commissioners of sewers of the City of London. (T. C.) ROANNE, a town of France, at the head of an arron- dissement in the department of the Loire, lies on the left bank of the Loire in 46 2' 26" N. lat. at a height of 912 feet above the sea. It is now the point of junction for the railway from Paris (262 miles north-north-west) to Lyons (50 miles south-east), via Tarare, with the line from Paris to St Etienne (50 miles south -south -east), and a branch connecting Roanne with Paray le Monial ; and as the terminus of the Roanne- Digoin Canal (1832-38) the town is the real starting-point of the Loire navigation. Besides the modern town-house (1868-73), it is enough to mention the ruins of a castle with a tower dating from the llth century, and a fine bridge of seven arches con- necting Roanne with the industrial suburb of Le Coteau on the right bank of the river. Cotton is the staple manufacture, employing 1200 hands. Hosiery, hats, woollen yarn, weaving looms, chemicals, and paper are also produced ; and, as the town stands in the centre of the Loire and Rhone coal-field (output 4224 tons in 1884) and" in the neighbourhood of the St Etienne coal-field, it has a considerable trade in coal and coke. In 1881 Roanne had a population of 24,992. Roanne (Rodomna, Ptolemy; Roidoinna, Tab. Peut.) was an ancient city of the Segusiani and a station on the great Roman road from Lyons to the ocean. The absence of coins later than the time of Coustantius II. among the numerous local relics of the Roman period seems to show that the town was sacked by the barbarians in the 4th century. In 1447 the lordship of Roanne became the property of the celebrated banker Jacques Cceur. A favourite scheme of his was to make the town a great industrial centre by regulating the course of the Reuaison, an affluent from the Monts de la Madeleine which joins the river a little higher up ; his death prevented its execution, but the subject has since been frequently revived. ROBBERY. See THEFT. ROBBIA, DELLA, the name of a family of great dis- tinction in the annals of Florentine art. Its members are enumerated in chronological order below. 1 I. LUCA BELLA ROBBIA (1399 or 1400 2 -1482) was the son of a Florentine named Simone di Marco della Robbia. According to Vasari, whose account of Luca's early life is little to be trusted, he was apprenticed to the silversmith Leonardo di Ser Giovanni, who from 1355 to 1371 was working on the grand silver altar frontal for the cathedral at PISTOIA (q.v.) ; this, however, appears doubtful from the great age which it would give to Leonardo, and it is more probable that Luca was a pupil of Ghiberti. During the early part of his life Luca executed many important and exceedingly beautiful pieces of sculpture in marble and bronze. In technical skill he was quite the equal of Ghiberti, and, while possessing all Donatello's vigour, dramatic power, and originality, he very frequently ex- celled him in grace of attitude and soft beauty of expres- sion. No sculptured work of the great 15th century ever surpassed the singing gallery which Luca made for the cathedral at Florence between 1431 and 1440, with its ten magnificent panels of singing angels and dancing boys, far exceeding in beauty those which Donatello in 1433 sculptured for the opposite gallery in the same choir. This magnificent work now lies scattered in various parts of the 1 Genealogical tree of Della Robbia sculptors : Simoue di Marco. Marco. 1 Andrea (1435-1525). Luca (1400-1482). Oirolamo Luca Paolo Giovanni Marco (1488-150(5), (1475-15507), (1470- ?), (1469-15297), (1468- ?), worked mostly worked in Dominican worked mainly Dominican in France. Florence monk. in Florence. monk. and Rome. 2 Not 1388, as Vasari says. See a document printed by Gaye, Car- tegrjio Inedito, i. pp. 182-186.
