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MENDE , a See also:town of See also:south-eastern See also:France, See also:capital of the See also:department of See also:Lozere, S9 M. N.N.E. of See also:Millau by See also:rail. Pop. (1906), town 5246; See also:commune 7007. Mende is picturesquely situated on the See also:left See also:bank of the Let, and at the See also:foot of the Mimat cliff, which rises l000 ft. above the town, and terminates the Causse de Mende. The town is the seat of a bishopric. Its See also:cathedral of St See also:Peter was founded in the 14th See also:century by See also:Pope See also:Urban V., a native of the See also:district, but the two towers, respectively 28o and 210 ft. high, were added by See also:Bishop See also:Francois de la Rovere in the See also:early See also:part of the 16th century. Partly destroyed during the devastation of the town by the Protestants in 1579 and 158o, it was rebuilt in the 17th century, and in 1874 a statue of Urban V. was erected in front of it. A See also:Renaissance See also:tower of the See also:ancient citadel now serves as the See also:belfry of the See also: Mende (Mimate) See also:grew up around the hermitage, partly excavated in the See also:side of the Mimat cliff, to which St Privat, bishop of Javols, retreated after the destruction of that town, and where he was subsequently slain by the See also:Vandals, who had pursued him thither, about 408. In the 14th century the new town became the See also:civil, as it had previously been the ecclesiastical, capital of the Gevaudan district. MENDEL$EFF, DMITRI IVANOVICH (1834-1907), See also:Russian chemist, the youngest of a See also:family of seventeen, was See also:born at See also:Tobolsk, See also:Siberia, on the 7th of See also:February (N.s.) 1834. After attending the gymnasium of his native See also:place, he went to study natural See also:science at St See also:Petersburg, where he graduated in See also:chemistry in 1856, subsequently becoming privatdozent. In 186o he went to See also:Heidelberg, where he started a laboratory of his own, but returning to St Petersburg in 1861, he became See also:professor of chemistry in the technological See also:institute there in 1863, and three years later succeeded to the same See also:chair in the university. In 1890 he resigned the professorship, and in 1893 he was appointed director of the See also:Bureau of Weights and See also:Measures, a See also:post which he occupied till his See also:death. Mendeleeff's See also:original See also:work covered a wide range, from questions in applied chemistry to the most See also:general problems of chemical and See also:physical theory. His name is best known for his work on the Periodic See also:Law. Various chemists had traced numerical sequences among the atomic weights of some of the elements and noted connexions between them and the properties of the different substances; but it was left to him to give a full expression to the generalization, and to treat it not merely as a See also:system of classifying the elements according to certan observed facts, but as a " law of nature" which could be relied upon to predict new -factsand to disclose errors in what were supposed to be old facts. Thus in 1871 he was led by certain gaps in his tables to assert the existence of three new elements so far unknown to the chemist, and to assign them definite properties These three he called ekaboron, ekaaluminium, and ekasilicon; and his prophecy was completely vindicated within fifteen years by the See also:discovery of See also:gallium in 1871, See also:scandium in 1879, and See also:germanium in 1886. Again, in several cases he ventured to question the correctness of the " accepted atomic weights," on the ground that they did not correspond with the Periodic Law, and here also he was justified by subsequent investigation. In 1902, in an " See also:attempt at a chemical conception of the See also:ether," he put forward the See also:hypothesis that there are in existence two elements of smaller atomic See also:weight than See also:hydrogen, and that the lighter of these is a chemically inert, exceedingly See also:mobile, all-penetrating and all-pervading See also:gas, which constitutes the See also:aether. Mendeleeff also devoted much study to the nature of such " indefinite " compounds as solutions, which he looked upon as homogeneous liquid systems of unstable dissociating compounds of the solvent with the substance dissolved, holding the See also:opinion that they are merely an instance of See also:ordinary definite or atomic compounds, subject to See also:Dalton's See also:laws. In another department of physical chemistry he investigated the expansion of liquids with See also:heat, and devised a See also:formula for its expression similar to See also:Gay-Lussac's law of the uniformity of the expansion of gases, while so,far back as 1861 he anticipated T. See also:Andrews's conception of the See also:critical temperature of gases by defining the See also:absolute boiling-point of a substance as the temperature at which cohesion and heat of See also:vaporization become equal to zero and the liquid changes to vapour, irrespective of the pressure and See also:volume. Mendeleeff wrote largely on chemical topics, his most widely known See also:book probably being The Principles of Chemistry, which was written in 1868-1870, and has gone through many subsequent See also:editions in various See also:languages. For his work on the Periodic Law he was awarded in 1882, at the same See also:time as L. See also:Meyer, the See also:Davy See also:medal of the Royal Society, and in 1905 he received its See also:Copley medal. He died at St Petersburg on the 2nd of February 1907. See W. A. See also:Tilden, " Mendeleeff Memorial Lecture," Jour. Chem. See also:Soc., 95, p. 2077. Additional information and CommentsThere are no comments yet for this article.
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