C L A U S I U S — C L A Y S is the seat of the South-West Presbyterian University. Population (1880), 3880; (1890), 7924; (1900), 9431. Clausius, Rudolf Julius Emmanuel (1822-1888), German physicist, was born on 2nd January 1822 at Koslin, in Pomerania. After attending the Gymnasium at Stettin, he studied at Berlin University from 1840 to 1844. In 1848 he took his degree at Halle, and in 1850 was appointed professor of physics in the Royal Artillery and Engineering School at Berlin. Late in the same year he delivered his inaugural lecture as privat docent in the University. In 1855 he became an ordinary professor at Zurich Polytechnic, accepting at the same time a professorship in the University of Zurich. In 1867 he moved to Wurzburg as professor of physics, and two years later was appointed to the same chair at Bonn, where he died on 24th August 1888. During the FrancoGerman war he was at the head of an ambulance corps composed of Bonn students, and received the Iron Cross for the services he rendered at Vionville and Gravelotte. The work of Clausius, who was a mathematical rather than an experimental physicist, was concerned with many of the most abstruse problems of molecular physics. By his restatement of Carnot’s principle he put the theory of heat on a truer and sounder basis, and he deserves the credit of having made thermo-dynamics a science; he enunciated the second law, in a paper contributed to the Berlin Academy in 1850, in the well-known form, “Heat cannot of itself pass from a colder to a hotter body.” His results he applied to an exhaustive development of the theory of the steam-engine, laying stress in particular on the conception of entropy. The kinetic theory of gases owes much to his labours, Clerk Maxwell calling him its principal founder. It was he who raised it, on the basis of the dynamical theory of heat, to the level of a theory, and he carried out many numerical determinations in connexion with it, e.g., of the mean free path of a molecule. To Clausius also was due an important advance in the theory of electrolysis, for he put forward the idea that molecules in electrolytes are continually interchanging atoms, the electric force not causing, but merely directing, the interchange. This view found little favour until 1887, when it was taken up by Arrhenius, who adduced additional arguments in its support, and formed from it the hypothesis of electrolytic dissociation now widely accepted. Clay, Charles (1801-1893), English surgeon, was born at Bredbury, near Stockport, on 27th December 1801. He began his medical education as a pupil of Mr Kinder Wood in Manchester (where he used to attend Dalton’s lectures on chemistry), and in 1821 went to Edinburgh to continue his studies there. Qualifying in 1823, he began a general practice in Ashton-under-Lyne, but in 1839 removed to Manchester to practise as an operative and consulting surgeon. It was there that, in 1842, he first performed the operation of ovariotomy with which his name is associated. On this occasion it was perfectly successful, and when fifteen years afterwards he published an analysis of his cases he was able to show a mortality only slightly above 25 per cent. Although his merits in this matter have sometimes been denied, his claim to the title “Father of Ovariotomy” is now generally conceded, and it is admitted that he deserves the credit not only of having shown how that operation could be made a success, but also of having played an important part in the advance of abdominal surgery for which last century was conspicuous. In spite of the claims of a heavy practice, Clay found time for the pursuit of geology and archaeology. Among the books of which he was the author were a volume of Geological Sketches of Manchester
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and a History of the Currency of the Isle of Man, and his collections included over a thousand editions of the Old and Hew Testaments, and a remarkably complete series of the silver and copper coins of the United States of America. He died at Poulton-le-Fylde, near Preston, on 19th September 1893. Clay CrOSS, a town in the Chesterfield division of Derbyshire, England, 5 miles south from Chesterfield, with a station on the Midland Railway. Since 1894 it has been governed by an urban district council. The Clay Cross Colliery and Ironworks Company employ a great number of hands. Population (1891), 7727; (1901), 8348. Clay, Frederic (1840-1889), English musical composer, was born in Paris in 1840. He studied music under Molique in Paris, and Hauptmann at Leipzig. With the exception of a few songs and two cantatas, The Knights of the Cross (1866) and Lalla Rookh (1877),'his compositions were all written for the stage; but he will be best remembered as the composer of “ I’ll sing thee songs of Araby.” Clay’s first public appearance was made with an opera entitled Court and Cottage, the libretto of which was written by Tom Taylor. This was produced at Covent Garden in 1862, and was followed by Constance (1865), Ages Ago (1869), and Princess Toto (1875), to name only three of many works which have long since been forgotten. The last two, which were written to libretti by W. S. Gilbert, are among Clay’s most tuneful and most attractive works. He wrote part of the music for Babil and Bijou (1872), and The Black Crook (1873), both of which were produced at the Alhambra. He also furnished incidental music for a revival of Twelfth Night, and for the production of James Albery’s Oriana. His last works, The Merry Duchess (1883), and The Golden Ring (1883), the latter written for the reopening of the Alhambra, which had been burned to the ground the year before, showed an advance upon his previous work, and rendered all the more regrettable the stroke of paralysis which crippled his physical and mental energies during the last few years of his life. He died at Great Marlow in 1889. (e. a. s.) Clays, Paul Jean (1819-1900), Belgian artist, was born at Bruges in 1819, and died at Brussels in 1900. He was one of the most esteemed marine painters of his time, and early in his career he substituted a sincere study of nature for the extravagant and artificial conventionality of most of his predecessors. When he began to paint, the sea was considered by Continental artists as worth representing only under its most tempestuous aspects. Artists cared only for the stirring drama of storm and wreck, and they clung still to the old-world tradition of the romantic school. Clays was the first to appreciate the beauty of calm waters reflecting the slow procession of clouds, the glories of sunset illuminating the sails of ships or gilding the tarred sides of heavy fishing-boats. He painted the peaceful life of rivers, the poetry of wide estuaries, the regulated stir of roadsteads and ports. And while he thus broke away from old traditions he also threw off the trammels imposed on him by his master, the marine painter Gudin. Endeavouring only to give truthful expression to the nature that delighted his eyes, he sought to render the limpid salt atmosphere, the weight of waters, the transparence of moist horizons, the gem-like sparkle of the sky. A Fleming in his feeling for colour, he set his palette with clean strong hues, and their powerful harmonies were in striking contrast with the rusty, smoky tones then in favour. If he was not a “ luminist ” in the modern use of the word, he deserves at any rate to be classed with the founders of the modern naturalistic school. This conscientious and healthy interpretation, to which the artist remained faithful, without any important change,
