ROTATION OF CROPS 126 ROTHERMERE gathered strength when it was consid- ered that the earth was not a sphere but an oblate spheroid, as if rapid whirling had bulged it out at the equa- tor, that Jupiter was yet more flattened at the poles than the earth, and that the direction of the trade winds, cy- clones, etc., seemed the result of rotation. In 1851 Foucault completed the proof by making visible to the eye that a pendu- lum with a very long string alters its direction in a way which cannot be accounted for except by rotation (see Gyroscope). The rotation of the earth is performed with a uniform motion from W. to E. and occupies the interval in time which would elapse between the departure of a star from a certain point in the sky and its return to the same point again. The only motions which interfere with its regularity are those of the precession of the equinoxes and nutation (see Precession). The time taken for the rotation of the earth measures the length of its day. So with the other planets. The sun also ro- tates as is shown by the movement of spots across its disk (see Sun). The earth's rotation slightly increases the force of gravity in moving from the equator to the poles. Sir William Thom- son reasoning from some small anoma- lies in the moon's motion, inferred that 10,000,000 years ago the earth rotated one-seventh faster than it does now, and that the centrifugal force then was to that now as 64 to 49. In botany, a rotary movement of a layer of protoplasm, investing the whole internal surface of a cell, as well seen in Chara, etc. It was first investigated by Corti in 1774. Called more fully in- tercellular rotation. In physiology: (1) The movement of a bone round its axis, without any great change of situation. (2) The moving of the yolk in an ovum at a certain stage of development on its axis in the surrounding fluid. This was first observed by Leuwenhoeck in 1695. ROTATION OF CROPS, the cultiva- tion of a different kind of crop each year, for a certain period, to prevent the exhaustion of the soil. If a plant re- quiring specially alkaline nutriment be planted year after year in the same field or bed, it will ultimately exhaust all the alkalies in the soil and then languish. But if a plant be substituted in large measure requiring siliceous elements for its growth, it can flourish where its al- kaline predecessor is starved. Mean- while the action of the atmosphere is continually reducing to a soluble condi- tion small quantities of soil, thus re- storing the lost alkalies. Manure will replace lost elements more quickly. The period of rotation is often made four years. ROTHENSTEIN, WILLIAM, a Brit- ish artist. He was born in Bradford, Yorkshire, England, in 1872, and was educated at Bradford Grammar School. He went to London in 1888 and worked under Legros at the Slade School and afterward in Paris, where he first ex- hibited. In 1893 he went to Oxford and drew portraits and settled in Chelsea shortly afterward. He has pictures and portraits in the Tate Gallery; British Museum; Victoria and Albert Museum; St. John's College, Cambridge; Trinity Hall, Cambridge; Carnegie Institute, Pittsburgh; Magdalen College, Oxford; National Portrait Gallery, Edinburgh; Luxembourg, Paris, etc. His publica- tions include: "Oxford Characters," "English Portraits," "Manchester Por- traits," "Liber Juniorum"; six portraits of Rabindranath Tagore. ROTHERHAM, a manufacturing town in the West Riding of Yorkshire, Eng- land, on the Don, here joined by the Rother; 5 miles E. N. E. of Sheffield. Its chief glory is the magnificent cruci- form church, Perpendicular in style, with crocketed spire and fine W. front. It is probably somewhat earlier than its reputed founder, Thomas de Rotherham, Archbishop of York (1423-1500) ; in 1875 it was restored by Sir G. G. Scott. A handsome edifice in the Collegiate Gothic style, built for an independent college in 1875, has been bought and applied to the purpose of a grammar school (1843), at which Bishop Sander- son was educated. There are also a mechanics' institute (1853) ; a free li- brary (1881) ; an infirmary (1870) ; a covered market (1879) ; public baths (1887) ; a park (1876) of 20 acres, 300 feet above the town; and the Clifton Park of 57 acres. The manufactures include stoves, grates, chemicals, pot- tery, glass, railway carriages, etc. Eben- ezer Elliott was a native of the suburb of Masborough, which is included within the municipal boundary, incorporated in 1871. Roche Abbey, a ruin, 8 miles E. S. E., was a Cistercian foundation (1147) ; and 8 miles N. E. is Conisbor- ough Castle. Pop. (1919) 71,913. ROTHERMERE, HAROLD SIDNEY HARMSWORTH, FIRST VISCOUNT, a British newspaper proprietor. He was born in 1868 at Dublin, Ireland, son of Alfred Harmsworth, and removing to England, following the example of his brother, Lord Northcliffe, became inter- ested in newspapers, of which he is the proprietor of several. He endowed the King Edward VII. Chair of English Lit-
