similar species with narrower and more pointed leaves, of the same color on both sides, is a native of Western Asia, and apparently also of Southern Spain. Rhododendron catawbiense, a native of the southern Alleghanies, with large purple flowers, and Rhododendron arboreum, a native of Nepal, with very dense heads of large scarlet flowers and leaves 12 to 18 inches long, attaining a height of 30 to 40 feet in its native

RHODODENDRON (Rhododendron ponticum).

country, are fine and well-known species; Rhododendron Californicum and Rhododendron macrophyllum are among the most conspicuous species of the Pacific Coast region. Most of the extremely numerous varieties common in gardens and shrubberies have been produced from them. In many if not most of the hybrids, Rhododendron Catawbiense enters, and in a list published in 1871, 250 named hybrids of this species are mentioned. Since that time the number has undoubtedly greatly increased.

Many splendid species of Rhododendron have been discovered in the Himalaya, the Khasia Hills, and other mountainous parts of India, by Hooker and others; and some of them have been introduced into cultivation. Rhododendron grande has very beautiful flowers 41⁄2 inches in diameter. Rhododendron Maddeni, Rhododendron Griffithianum, Rhododendron Edgeworthii, and others have white flowers. Rhododendron Dalhousia is remarkable as an epiphyte, growing on magnolias, laurels, and oaks. It is a slender shrub, bearing from 3 to 6 white lemon-scented terminal bells, 41⁄2 inches long. Rhododendron Nuttallii has fragrant white flowers, said to be larger than those of any other species. All these belong to the Himalayas. In more southern latitudes, as on the Neilgherry Hills and on the mountains of Ceylon, Rhododendron barbatum prevails as a timber tree, a blaze of crimson when in flower. Rhododendron Keysii and Rhododendron cinnabarinum, natives of Northern India, have flowers with nearly tubular corollas. Rhododendron ferrugineum and Rhododendron hirsutum are small Alpine shrubs from 1 to 3

feet in height with umbellate clusters of carminecolored flowers among the finest ornaments of alpine scenery. They are called alpenrose (alpine rose) by the Germans, and are not easily cultivated in gardens. The flora of the Himalaya contains a number of similar small species. Rhododendron setosum, a dwarf shrub with strongly scented leaves, clothes the mountains in Eastern Nepal at an elevation of 12,000 feet and upward, with a green mantle, brilliant with flowers in summer. Rhododendron nivale is the most alpine of woody plants, spreading its small woody branches close to the ground, at an elevation of 17,000 feet in Sikkim. Rhododendron lapponicum, a procumbent shrub, with small flowers, grows as far north as human settlements have reached in Europe and Asia. An oil obtained from the buds of Rhododendron ferrugineum and Rhododendron hirsutum have been used by the inhabitants of the Alps under the name olio di marmotta, as a remedy for various ailments. The flowers of Rhododendron arboreum are said to be eaten in India, and Europeans make a jelly of them. The wood of some of the larger species is white, hard, and close-grained, and has been recommended as a possible substitute for boxwood. Rhododendrons are not of difficult culture, a soil containing plenty of leaf mold and protection from drought and winter scalding being the prime necessities for growing the hardier species in shrubberies and parks. See Colored Plate of AZALEAS AND RHODODENDRONS.

RHODONITE (from Gk. pódov, rhodon, rose). A mineral manganese silicate that crystallizes in the triclinic system, has a vitreous lustre, and is usually red, although sometimes green or yellow. It occurs frequently in association with iron and zinc ores, and is found in Sweden, the Harz, the Urals, and in the United States at various localities in Massachusetts, and in Sussex

County, N. J., where part of the manganese is replaced by zinc, giving rise to a variety known as fowlerite. The massive varieties of this mineral, especially those found in the Ekaterinburg District in the Urals, are used for ornamental purposes, as for table tops, etc., while varieties from other places are used to a limited extent as gems.

RHODOPHYCEE (Neo-Lat. nom. pl., from Gk. pódov, rhodon, rose, + øûkoç, phykos, seaweed). The red algæ. The most beautiful of the four great groups of algae. Some are very complex in structure, but in general they show less vegetative differentiation than do the brown algæ (Phæophyceæ, q.v.). Their peculiarities lie chiefly in a highly developed method of sexual reproduction, resulting in a complex fruit (cystocarp), which contains the carpospores. (Figs. 1, 2.) The male cells (spermatia) are non-motile, and fuse with a thread-like female receptive organ (trichogyne). There is also a form of asexual reproduction generally of four special spores (tetraspores). (Fig. 1.) Most Rhodophyceæ are red or reddish brown, a color due to a peculiar pigment (phycoerythrin) which obscures the green pigment (chlorophyll).

The form of the body ranges from minute filaments of great delicacy to broad membranes and thick cartilaginous fronds. Some of the membranous forms are several feet long (Delesseria), and may be differentiated into a stem and leaf-like out-growths. Others form filamentous branching tufts (Callithamnion, Dasya). Some groups bear

and in Anglo-Saxon poetry usually consisted of a three-fold repetition of the alliterated sound, as in the third and fourth lines of the first quotation above given. End-rhymes, on the other hand, may be completed within a single verse, but are ordinarily between two or more verses, the number being determined by the stanzaic structure or the taste of the poet; in the rondeau, for instance, one rhyme is repeated eight times and the other five. Not infrequently poems are constructed having both styles of rhyme, as in Shelley's Cloud:

I bring fresh showers for the thirsting flowers,
From the seas and the streams;

I bear light shade for the leaves when laid
In their noonday dreams.

Rhymes, of whatever sort, are in modern poetry always placed upon accented syllables, and endrhymes are characteristically placed either at the end of the verse or at the end of the colon, as in the first and third verses here given. They may, however, be placed elsewhere, even at the beginning of the verse, as in the second citation from Lanier's Symphony. In complicated structures they are often used with less regard to regularity, internal rhymes being carried on in verse endings, or placed within the verse itself without regard to cæsural pauses. In general, however, internal rhymes irregularly placed convey an effect of assonance rather than of true rhyme, and many poets make use of assonance in preference to it, when so placed. As to the relation of rhyming verses, this is determined either by the form of the stanza or in non-stanzaic rhymed composition by some set order, as the couplet, which the poet may determine, or again the rhymes may occur irregularly. Stanzas are of indefinite variety, and the poet is at liberty to invent whatever forms may please

his ear.

Not all languages agree as to the nature of the adequate rhyme. In English, words which rhyme perfectly must agree in all the sound elements succeeding the initial element of the last accented syllable, and in this element they must differ. In French, on the other hand, such a rhyme is only suffisante, the riche or perfect rhyme having identical all the elements in the rhyming syllables. Thus, grows and rose form a perfect rhyme in English, rose and arrose in French. Rarely in English an identical rhyme is used provided the sense be changed, as reign with rein, lo with low (change of sense is also always necessary in French), but the change must be more than a mere negation; in no case should close and disclose be rhymed, nor words having the same root, as compute, dispute. When a word is repeated to rhyme with itself, as is frequently the case in Poe's poems, for example, it has the value of a refrain rather than of a true rhyme, and in all such cases there should be at least one other word rhymed with it. There are a few words in English the pronunciation of which may be altered to suit the needs of rhyme; thus, wind (noun) may be rhymed with blind, etc., but this is only a form of poetic archaism, reverting to the original pronunciation of the word. Rhymes are masculine' and 'feminine;' masculine when the rhymed syllable is also the chief accent of the word, aver, deter; mar, tar; feminine when it is followed by unaccented syllables, marry, tarry; tenderly, slenderly. Sometimes a secondary accent is made to carry the rhyme, but in such cases it is generally rhymed

with a word having no great rhetorical stress or having other words rhymed with it. The use of feminine rhymes is the less common in English, and they are never to be found in the complicated form to be met with in some other languages. (Compare the Persian under RUBAIYAT.) They occur most freely in satirical verse, which often takes liberties with rhyme that no serious poetry could tolerate. An example from Lowell

is:

Though you brag of your New World, you don't
half believe in it;

And as much of the Old as is possible weave in it. Rhyme was of relatively slight value in verse which depended upon quantity rather than accent and in languages which abounded in elaborate inflections. It was not until the classical Latin gave way to the vulgar speech that rhyme became the rule, first in the early hymns of the Christian Church. It is possible that an ancient Celtic influence may have aided this development, since the Celts used rhyme in the oldest Celtic poetry preserved to us. Rhyme was elaborately developed among the Persians and Arabs of medieval times, but it is not known from what influence it was derived. It seems most probable that the simple repetitions, in which most primitive poetry abounds, form the basis from which rhyme naturally arises. Consult: Corson, Primer of English Verse (Boston, 1893); Gummere, Handbook of Poetics (Boston, 1895); Schipper, Englische Metrik (Bonn, 1881-88).

RHYNCHOCEPHALIA,

rin'ko-se-fa'lĭ-å (Neo-Lat. nom. pl., from Gk. púyxos, rhynchos, An order of snout kepaλh, kephale, head). primitive reptiles, represented in modern times which lives on islands off the coast of New Zeaby a single survivor, Sphenodon or Hatteria, land, and in ancient times by a large number of creatures whose fossil remains are found in Permian, Mesozoic, and Eocene rocks. received its name from the beak-like rostrum on the skulls of some of its typical species. It includes the earliest and most primitive reptiles, and also the birds. The suborder Proterosauria,

RHYNCHOCEPHALIA.

This order

1, Skull of Palæohatteria, superior aspect; 2, the same, lateral aspect; 3, a dorsal vertebra of Nassaurus claviger: c, centrum; j, jugal; m, maxilla; q, quadrate bone.

or Proganosauria, includes the most primitive forms, in which the teeth are of uniform shape and parts of the skeleton are still cartilaginous. Palæohatteria from the Lower Permian of Saxony is the earliest known reptile. It had a lizard-like body about 18 inches long, with a long tail, large head, very large eyes, and numerous large conical teeth that are fused with the jaw bones, and also small teeth on the palate. The

RHYN'CHONEL/LA

(Neo-Lat. nom. pl., from Gk. pyxos, rhynchos, snout). A genus of brachiopods, scarce but widespread in modern seas, but very abundant anciently, and represented in almost every geological formation from the Ordovician upward. About 600 species have been described, mostly from the Mesozoic rocks, of which the Jurassic and Cretaceous groups are especially prolific. Most of the ancient forms are doubly convex shells with prominent though small ventral beaks, and with surfaces marked by strong, usually angular radial plications, and with a more or less elevated median fold and sinus. The structure of the shell in most genera is non-punctate, a character by which the species may most readily be distinguished from the closely similar species of Terebratulidæ. Consult: Hall and Clarke, Paleontology of New York, vol. viii., part ii. (Albany, 1894); Davidson, "Monograph of the Recent Brachiopoda," Transactions of the Linnean Society, vol. iv. (London, 1886-88).

RHYOLITE (from Gk. púa, rhyax, stream, especially of lava, from peiv, rhein, to flow + Neos, lithos, stone), LIPARITE, NEVADITE. An igneous rock of porphyritic texture and siliceous composition, generally with a crumply, banded (rhyolitic) texture, due to the arrangement of its constituent minerals by flowage. Rhyolites are also frequently glassy, vesicular, scoriaceous, or pumiceous. When compact and massive, rhyolites are designated as rhyolite porphyries (formerly called quartz porphyries, and then supposed to be of geological age older than the Tertiary). In chemical composition rhyolites have about the same range as the granites. They average: Silica, 75 per cent.; alumina, 13 per cent.; sesquioxide and protoxide of iron, each 1 per cent.; oxide of lime, 1 per cent.; oxide of sodium, 3 per cent.; oxide of potassium, 6 per cent. Varieties rich in oxide of sodium are designated soda-rhyolites

(pantellerites). Rhyolites are for the most part surface lavas or are intruded in other rocks as dikes or sills. Very extensive areas of rhyolite are found in the Cordilleran mountain system of the Western Hemisphere. Rhyolites when of unusually coarse grain are now designated by the variety name, Nevadite.

RHYS, res, ERNEST (1859-). An English author, born in London, July 17, 1859. He was educated at schools in Carmarthen, South Wales, at Bishop-Stortford and at Newcastle-on-Tyne, and became a mining engineer (1877). In 1885 he abandoned the profession for general literature. In 1887 he came to the United States on a lecturing tour. His writings on Welsh subjects are popular and are to be distinguished from those of the profound Celtic scholar John Rhys (q.v.). He edited the Camelot series of popular reprints and translations (65 vols., 1886-91); Dekker's Plays for the Mermaid Series (1888); The Lyric Poets (12 vols., 1894-99); Literary Pamphlets (1897); and other works. His writings include: The Great Cockney Tragedy (1891); A London Rose and Other Rhymes (1894); Welsh Ballads and Other Poems (1898); Frederick Lord Leighton, a biography (1898, which had been preceded by an earlier study in 1895); and two romances, The Fiddler of Carne, having a Welsh heroine (1896), and The Whistling Maid (1900).

He

RHYS, JOHN (1840-). A Welsh author and professor of Celtic at Oxford since 1877. was born in Cardiganshire in 1840 and educated at Bangor Normal College, Jesus College, Oxford, the Sorbonne, Heidelberg, and Leipzig. In 1871 he became school inspector for Flintshire and Denbighshire; fellow of Jesus College in 1881; Hibbert lecturer, 1886; Rhind lecturer on archæology in Edinburgh, 1889; and has seen service on numerous commissions on education, reforms and land movements connected with Wales. His works are: Lectures on Welsh Philology (1877); Celtic Britain (1882); Celtic Heathendom (1886); Studies in the Arthurian Legend (1891); Inscriptions and Language of the Northern Picts (1892); Rhind Lectures on the Early Ethnology of the British Isles (1890-91); Celtic Folk-Lore (1901); and in conjunction with Mr. D. Brynmor-Jones, The Welsh People (1900). Professor Rhys has also coöperated in the production of several important editions of Welsh texts and his contributions to Celtic scholarship have been various and important. To his native and unsurpassed knowledge of Wales and of the Welsh language he has added wide research in the other languages of the Celtic group, and in the history and antiquities of the Celtic peoples. Besides doing valuable linguistic work in early Welsh and Manx, he has made himself the chief living authority on the Ogam inscriptions. His studies on folk-lore, mythology, and religion have been learned and brilliant, but rather bold in conjecture. The editions of Welsh texts which he has brought out in collaboration with Professor Morris Jones and Mr. J. Gwenogvryn Evans are models of accurate editing.

RHYTHM (Lat. rhythmus, from Gk. pu@ubs, rhythmos, rhythm, time, measure, from peiv, rhein, Skt. sru, to flow). A complex mental process which has been defined, from different points of view, as a temporal perception and as a regulated emotion. Objectively regarded, it is a regularly measured and regularly stressed movement in