RADISHTCHEFF. 645 RADOWITZ. family, and after several years as a page, edu- cated with eleven other young Russians at Leip- zig University. There lie spent four years, in which he was more deeply influenced by French philosopliy and the Encyeloptedists tlian by any part of his university curriculum. He returned to Russia in 1771, received a post in the customs administration, and, although he moved in the best society, intellectually, of Petersburg and knew 'oroncoti' and Kr^loff, made little stir un- til 1790. Then, under the influence of his liberal convictions patterning after Abb^ Raynal's His- torj of the Indies, with its philanthropic senti- ment, and after Sterne's Sentimental Joiiineii, he wrote his famous Journey from Saint Petersburg to Moscow, which, with all its humor and ex- cursive sentimentality, is a terribly vivid picture of Russian serfdom and contains a frank pro- gramme of emancipation, all the more bold for its appearance in the midst of a period of re- action. Catliarine sent the author to Ilimsk, in the Government of Irkutsk. He returned to Rus- sia in 1796 under Paul. Alexander made him a memlier of the legislative commission in 1801. But recognition came too late ; his exile had made him melancholy and half insane, and he com- mitted suicide. RADIUM (Xeo-Lat., from Lat. radius, ray). A radioactive substance first obtained from pitclildende by M. and Mme. Curie and M. Be- mont in 1898. Radium is considered to be an element and has many interesting properties ■which are described under Kadioaetirity (q.v. ). It maintains its own temperature I. .5° C. above its surroundings, and according to Professor Curie emits heat radiations without combustion or chemical change and without any appreciable decrease in its energy. Its spectrum has been examined by Demarcay and new and characteris- tic lines obtained which apparently demonstrate that it is an element. The atomic weight is stated at 225, and although it is believed to be a metal, it has been produced as yet only as a chloride or bromide. Radium is forty times as active as uranium, and its discovery and peculiar characteristics have given rise to many interesting physical speculations. It is enormously expen- sive to prepare, and in 1903 it was said that to produce a kilo of a chemically pure preparation of radium would cost $6,000,000, and that this quantity would require about 5000 tons of ura- nium residue at an expense of handling of about $2000 per ton. See Radioactivity; Polonium; I'ranium. RADIUS (Lat., rod, staff, spoke, semidiam- eter, ray). A straight line from the centre to any point on the circumference of a circle (q.v.). RADIUS OF CURVATURE. See Curve. RADIUS'-VECTOR ( Xeo-Lat., semidiameter- carrier). The linear coijidinate in a system of pohir coordinates. See Coordinates. RADIX (Lat., root). In mathematics, the b,T«e of a scale of notation or a system of powers. See Logarithms ; Scales of Notation. RADLOFF, riit'lof, Wilhelm (1837—). A German-Russian traveler and philologist. He was born in Berlin, studied there, at Halle, and at Jena, and in 1838 became instructor at Barnaul in Western Siberia, a position which he held until 1870. After act- ing (1871-84) as departmental inspector of Jlohammedan schools in Kazan. Radloff was appointed curator of the Asiatic Museum in Saint Petersburg. In I88ti he traveled in the Crimea and in 1887 in Lithuania for researcli in local dialects. His publications include; Probeii der Volkslitteratur der turkischen Stiimme Siidsi- hiriens (1866-96); Verstich eines Wcirterbiichs der Tiirkdialekte (1888 sqq. ); Das Schamanen- tum und sein Kultus (1885), two great works in Russian on '"Siberian Antiquities" (1888) and the ethnologj' of the Siberian Turkish peoples (1888) ; and Atlas der Altertlimer der ilonqolei (1892 sqq.). RAD'NORSHIRE. A southern inland coun- ty of Wales. Great Britain, bounded on the north by Montgomeryshire and Shropshire, and on the south and southeast by Brecknockshire and Herefordshire (Map: Wales, C 4). Area, 471 square miles. Groups of mountains, of which Radnor forest (2163 feet high) is the loftiest, cover the greater part of the country. The southeastern district is flat, with a gradual slope toward the east. Of the rivers, the chief of which flow southward, the principal is the Wye, which forms the greater part of the southern boundary. The county formerly com- prised large tracts of bog and moor land, which are in course of being gradually reclaimed and cultivated. In the east and southeast districts excellent wheat, barley, oats, and potatoes are grown. Capital, Radnor. Population, in I89I, 21.791; in 1901, 23.300. RADOM, ra'd6m. A government of Russian Poland. Area, 4470 square miles. It is some- what hilly in the south and level in the north. In the latter part are found also considerable stretches of marshland. The principal river is the Vistula, which forms a consideraljle part of the boundary. The climate is damp and un- healthful in the marshy districts. Agriculture is the principal industry. Cereals are raised for e.xport. There are a large number of iron works. Population, in 1897, 820.363. Capital, Radom. RADOM. The capital of the Government of Radom, in Russian Poland, situated on the Mleczna, about 60 miles south of Warsaw (Map: Russia, B 4). It is a well-built town, and has manufactures of machinery and leather. Population, in 1897, 28.750. Radom was the scene of a number of diets in the history of Poland. It was allotted to Austria at the third partition of Poland, and became part of the new Kingdom of Poland in 1815. RADOWITZ, ra'do-vlts. Joseph Maria von (1797-1853). A Prussian general and statesman, born at Blankenburg, Brunswick, the son of a nobleman of Hungarian descent. He entered the army in 1812. and was wounded at the battle of Leipzig. He became a teacher in the military school at Cassel and entered the Prussian service in 1823. In 1830 he became chief of the general staff of artillery. In 1836 Radowitz was sent as Prussian military commissioner plenipotentiary to the German Diet at Frankfort. In 1842 he was named ambassador extraordinary and minister plenipotentiary at the courts of Karlsruhe. Darmstadt, and Nassau; and in 1843 he was raised to the rank of major-general. He ex- ercised a marked influence over Frederick Wil- liam IV. His lively interest in the contempo- rary politics of Germany is shown in his writ-
