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Rh (2 vols., 1895-96), in the “Library of Early English Writers.” This includes many English prose treatises by Rolle, some beautiful examples of his lyric poems, and other treatises in prose and verse from northern MSS., some of which are attributed to Rolle, and others to his followers. Wynkyn de Worde printed in one volume, in 1506, Rycharde Rolle Hermyte of Hampull in his contemplacyons ''of the drede and love of God. . . and the Remedy ayenst the troubles'' of temptations. Neither of these are accepted by Dr Horstmann as Rolle's work. His Latin treatises, De emendatione vitae and De incendio amoris, the latter one of the most interesting of his works, because it is obviously largely autobiographical, were translated (1434-35) by Richard Misyn (ed. R. Harvey, Early English Text Soc., 1896). The Pricke of Conscience was edited (1863) by Richard Morris or the Philological Society. His Commentary on the Psalms was edited by the Rev. H. R. Bramley (Oxford, 1884). Ten prose treatises by Richard Rolle from the Thornton MS. (c. 1440, Lincoln Cathedral Library) were edited by Canon George Perry for the Early English Text Society in 1866. Partial editions of his Latin works are dated Paris (1510), Antwerp (1533), Cologne (1535-36), Paris (1618); and in vol. xxvi. of the “Bibliotheca Patrum Maxima” (Lyons, 1677). The office, which forms the chief authority for Rolle's life, was printed in the York Breviary, vol. ii. (Surtees Soc., 1882), and in Canon Perry's edition referred to above.

See also Percy Andreae, who collated eighteen MSS. in the British Museum in his Handschriften des Pricke of Conscience (Berlin, 1888); Studien über Richard Rolle von Hampole unter besonderer Berücksichtigung seiner Psalmencommentare, by H. Middendorff (Magdeburg, 1888), with a list of MSS., sources, &c.; J. Zupitza in Englische Studien (Heilbronn, vols. vii. and xii.); A. Hahn, Quellenuntersuchungen zu Richard Rolle's Englischen Schriften (Halle, 1900); and for his prosody, G. Saintsbury, ''Hist. of English Prosody'', vol. i.  ROLLER, a very beautiful bird, so called from its way of occasionally rolling or turning over in its flight, somewhat after the fashion of a tumbler-pigeon. It is the Coracias garrulus of ornithology, and is widely though not very numerously spread over Europe and Western Asia in summer, breeding so far to the northward as the middle of Sweden, but retiring to winter in Africa. It occurs almost every year in some part or other of the British Islands, from Cornwall to the Shetlands, while it has visited Ireland several times, and is even recorded from St Kilda. But it is only as a wanderer that it comes, since there is no evidence of its having ever attempted to breed in Great Britain; and indeed its conspicuous appearance—for it is nearly as big as a daw and very brightly coloured—would forbid its being ever allowed to escape a gun. Except the back, scapulars and tertials, which are bright reddish-brown, the plumage of both sexes is almost entirely blue—of various shades, from pale turquoise to dark ultramarine—tinted in parts with green. The bird seems to be purely insectivorous. The genus Coracias, for a long while placed by systematists among the crows, has really no affinity whatever to them, and is now properly considered to belong to the heterogeneous group of birds now associated as Coraciiformes, in which it forms the type of the family Coraciidae; and its alliance to the bee-eaters (Meropidae) and king-fishers (Alcedinidae) (q.v.) is very evident. Some eight other species of the genus have been recognized, one of which, C. leucocephalus or C. abyssinicus, is said to have occurred in Scotland. India has two species, C. indicus and C. affinis, of which thousands upon thousands used to be annually destroyed to supply the demand for gaudy feathers to bedizen ladies' dresses. One species, C. temmincki, seems to be peculiar to Celebes and the neighbouring islands, but otherwise the rest are natives of the Ethiopian or Indian regions. Allied to Coracias is the genus Eurystomus with some half-dozen species, of similar distribution, but one of them, E. pacificus, has a wider range, for it inhabits Australia and reaches Tasmania.

Madagascar has four or five very remarkable forms which have often been considered to belong to the family Coraciidae; and, according to A. Milne-Edwards, no doubt should exist on that point. Yet if any may be entertained it is in regard to one of them,

Leptosomus discolor, which, on account of its zygodactylous feet, some authorities place among the Cuculidae, while others have considered it the type of a distinct family Leptosomatidae. The genera Brachypteracias and Atelornis present fewer structural differences from the rollers, and perhaps may be rightly placed with them; but the species of the latter have long tarsi, and are believed to be of terrestrial habit, which rollers generally certainly are not. These very curious and in some respects very interesting forms, which are peculiar to Madagascar, are admirably described and illustrated by a series of twenty plates in the great work of A. Grandidier and A. Milne-Edwards on that island (Oiseaux, pp. 223–250), while the whole family Coraciidae is the subject of a monograph by H. E. Dresser, as a companion volume to his monograph on the Meropidae.

 ROLLER. For agricultural purposes the roller formerly consisted of a solid cylinder of timber or stone attached to a frame and shafts, but to facilitate turning two or more iron cylinders revolving on an axle are now generally used. The simplest form has a smooth surface. The diameter of the drum should be as great as possible—30 in. being a good size—because the larger this is the more easily it is pulled (within certain limits), while rollers of small diameter are heavier of draught and do their work less efficiently. The implement is used in spring and summer as an aid in pulverizing and cleaning the soil, by bruising clods and lumps of tangled roots and earth which the cultivator or other implement has brought to the surface; in smoothing the surface for the reception of small seeds or the better operation of the mower or reaper; in consolidating soil that is too loose in texture and pressing it down about the roots of young plants. In the case of young plants the roots are close to the surface, which must therefore be kept moist. This end is attained by the compression by the roller of the top-soil of which the capillarity, i.e. the power of drawing water from the sub-soil is thereby increased. On the other hand, when it is desired to conserve the soil-moisture, the roller may be followed by the harrow, which, by pulverizing the surface-soil, breaks the capillarity. Of the variations on the common smooth roller, the clod-crusher and the Cambridge roller are the most important. The clod-crusher combines weight with breaking power. The best-known form was patented about 1841 by Crosskill, and consists of a number of disks with serrated edges threaded loosely on an axle round which they revolve. The Cambridge roller carries on its axle a number of closely packed wheels, the rims of which narrow down to a wedge shape. The tubular roller, instead of drums, has tubes arranged longitudinally, producing a corrugated surface which is reproduced in the condition of the soil after it has been rolled.  ROLLER-SKATING, a pastime which, by the use of small wheels instead of a blade on the skate, has provided some of the pleasures of skating on ice without having ice as the surface (see 1911 Encyclopædia Britannica/Skating). Wheeled skates were used on the roads of Holland as far back as the 18th century, but it was the invention of the four-wheeled skate, working on rubber springs, by J. L. Plimpton of New York, in 1863, that made the amusement popular. Still greater advance was made by the Raymond skate with ball and cone bearings. The wheels or rollers were first of turned boxwood, but the wearing of the edges was a fault which has been surmounted by making them of a hard composition or of steel. The floor of the rink on which the skating takes place is either of asphalt or of wood. The latter is that always used in newly made rinks. The best floors are of long narrow strips of maple. Figure-skating on roller-skates is in some respects easier to learn than on ice-skates, the four points of contact given by the wheels rendering easier the holding of an edge; but some figures, such as loops, are more difficult.  ROLLIN, CHARLES (1661–1741), French historian and educationist, was born at Paris on the 30th of January 1661. He was the son of a cutler, and at the age of twenty-two was made a master in the College du Plessis. In 1694 he was rector of the university of Paris, rendering great service among other things by reviving the study of Greek. He held that post for two years instead of one, and in 1699 was appointed principal of the College de Beauvais. Rollin held Jansenist