battles of Brienne and Arcis sur Aube. He entered Paris with the allied sovereigns in March 1814, and returned with them to the congress of Vienna, where he appears to have acted as an intermediary between Metternich and the czar Alexander, when these great personages were not on speaking terms. During the succeeding years of peace he disappeared from the public view. He resumed his functions as chief of the staff, but his ardent ideas for reforming the army came to nothing in the face of the general war-weariness and desire to “ let well alone.” His zeal added to the number of his enemies, and in 1829, after he had been for twenty years a lieutenant field marshal, it was proposed to place him on the retired list. The emperor, unwilling to go so far as this, promoted him general of cavalry and shelved him by making him governor of a fortress. But very soon afterwards the Restoration settlement of Europe was shaken by fresh upheavals, and Radetzky was brought into the field of war again. He took part under Frimont in the campaign against the Papal States insurgents, and succeeded that general in the chief command of the Austrian army in Italy in 1834. In 18 36 he became a field marshal. He was now seventy years of age, but he displayed the activity of youth in training and disciplining the army he commanded. But here too he was in advance of his time, and the government not only disregarded his suggestions and warnings but also refused the money that would have enabled the finest army it possessed to take the field at a moment's notice. Thus the events of 1848 in Italy, which gave the old field marshal his place in history among the great commanders, found him, in the beginning, not indeed unprepared but seriously handicapped in the struggle with Charles Albert's army and the insurgents. How by falling back to the Quadrilateral and there, checking one opponent after another, he was able to spin out time until reinforcements arrived, and how thenceforward up to the final triumph of Novara on the 23rd of March 1849, he and his army carried all before them, is described in the article ITALIAN WARS. The well-disciplined sense of duty to the superior officer, which was remarked even in the brilliant and sanguine young army reformer of 1810, had become more intense in the long years of peace, and after keeping his army loyal in the midst of the confusion of 1848, he made no attempt to play the part of Wallenstein or even to assume Wellington's role of family adviser to the nation. While as a patriot he dreamed a little of a united Germany, he remained to the end simply the commander of one of the emperor's armies. He died, still in harness, though iniirm, on the 5th of January 1858.
In military history Radetzky's fame rests upon one great achievement, but in the history of the Austrian army he lives as the frank and kindly “ Vater Radetzky" whom the soldiers idolized. He was fortunate in the 'moment of his death. In the year following, another and a greater Italian war broke out, his beloved army, disintegrated by peace economies which the old field marshal had been unable any longer to redress by ceaseless personal training, and in addition suffering from divided command and confused staff work, was defeated in every encounter.
RADEVORMWALD, a town of Germany, in the Prussian Rhine province, ro m. E. from Remscheid, on the branch line of railway from Krebstige. Pop. (1905) IO,978. It consists of the town proper and of several suburbs, and has five Evangelical and two Roman Catholic churches. Its chief manufactures are skates, files, locks and similar articles, and it has also cloth and cotton factories.
See J. H. Becker, Geschichte der Stadt Radevormwald (Cologne, 1904).
RADHANPUR. a native state of India, in the Palanpur agency, Bombay. It is situated in the north-western corner of Gujarat, close to the Runn of Cutch. The country is aniopen plain without hills and with few trees. It contains an area of 1150 sq. 111. with a population in 1901 of 61,548, showing 'a decrease of 37 % during the decade, due to the results of famine. The estimated revenue is £27,000. The chief products are cotton, wheat and the common varieties of grain; the only manufacture of any importance is the preparation of a fine description of saltpetre. Radhanpur first came under British protection in 1813. The chief, whose title is Nawab, belongs to the Babi family, who have held power in Gujarat for more than two centuries. The town of Radhanpur had a population in 1901 of 11,879. It is a walled town, with an export trade in rapeseed, grain and cotton. A
RADIATA, a term introduced by Cuvier in 1812 to denote the lowest of his four great animal groups or “embranchements.” He defined them as possessing radial instead of bilateral symmetry, and as apparently destitute of nervous system and sense organs, as having the circulatory system rudimentary or absent, and the respiratory organs, on or coextensive with the surface of the body; he included under this title and definition five classes, -Echinodermata, Acalepha, Entozoa, Polypi and Infusoria. Lamarck (Hist. nat. d. Anim. s. Vertébres) also used the term, as when he spoke of the Medusæ as radtata medusaria et anomala; but he preferred the term Radiaria, under which he included Echinodermata and Medusæ. Cuvier's term in its wide extension, however, passed into general use; but, as the anatomy of the different forms became more fully known, the difficulty of including them under the common designation made itself increasingly obvious. Milne-Edwards removed the Polyzoa; the group was soon further thinned by the exclusion of the Protozoa on the one hand and the Entozoa on the other; while in 1848 Leuckart and Frey clearly distinguished the Coelenterata from the Echinodermata as a separate sub-kingdom, thus condemning the usage by which the term still continued to be applied to these two groups at least. In 1855, however, Owen included under Lamarck's term Radiaria the Echinodermata, Anthozoa, Acalepha and Hydrozoa, while Agassiz also clung to the term Radiata as including Echinodermata, Acalepha and Polypi, regarding their separation into Coelenterata and Echinoderrnata as “ an exaggeration of their anatomical differences ” (Essayon Classzjication, London, 1859). These attempts, hiowever, to perpetuate the usage were finally discredited by Hux1ey's important Lectures on Comparative Anatomy (1864), in which the term was finally abolished, and the “ radiate mob ” finally distributed among the Echinodermata, Polyzoa, .Vermes (Platyhelminthes), Coelenterata and Protozoa.
RADIATION, THEORY OF. The physical activities that flourish on the surface of the earth derive their energy, in a form which is highly available thermodynamically, from the radiation of the sun. This has been ascertained to be dynamic energy, transmitted in waves by the vibrations of a medium occupying space, as the energy of sound is transmitted by the vibrations of the atmosphere. The elasticity that transmits it may be assumed to be mathematically perfect: any slight loss in transit of the light from the most distant stars, which recent statistical comparisons of brightness with distance may possibly indicate, is to be explained far more suitably by the presence of nebulous matter than by any imperfection of the aether. The latter would thus be the one perfect frictionless medium known to us: it could not be such if it were constituted, like matter, of independent molecules. It is thus on a higher plane, and may even be considered to be »a dynamical' specification of space itself. A molecule of matter is a kinetic system compounded of simpler elements; its energy may be classified into constitutive energy essential to its continued existence, and vibratory energy which it can receive from or radiate away into aether. A piece of matter isolated in free aether would in time lose ag energy of the latter type by radiation; but the former will remain so long as the matter persists, along with the energy of the uniform translator motion to which it is ultimately reduced. Thus all matter is in continual exchange of vibratory energy with the aether: it is with the laws of this exchange of energy that the general theory of Radiation deals, as distinguished from the mechanism of the ethereal vibrations, which is usually treated as the Theory of Light (see AETHER).
1. The foundation of this subject is the principle, arrived