a wave running all along it with immense rapidity. In this case it is evident that the earthquake wave must have had its front oblique to the direction of the wall just as an obliquely held ruler runs along the edge of a page of paper while it advances, like a wave of the sea, perpendicularly to its own length.-Familiar Lectures on Scientific Subjects. ERSCHEL, SIR WILLIAM, an Anglo-German astronomer; born at Hanover, Prussia, November 15, 1738; died at Slough, near Windsor, England, August 25, 1822. He was the son of a musician of Hanover. His early educational advantages were not great, but he repaired all their deficiencies by his own efforts, and became, not only a skilful musician, but a fine mathematician. About 1758 he went to England. After several years of teaching music he obtained the position of organist in a fashionable church in Bath, in which city he became the leading musical authority. While practicing his profession he devoted his leisure to astronomical research. In 1772 he was joined by his sister Caroline, who became his efficient co-operator both in music and astronomy. Unable to purchase a telescope, Herschel set about constructing one, and in 1774 completed one of six feet focal length. All the leisure of sister and brother was now given to astronomy the nights to observation, and the days to the toil of grinding and polishing specula. In 1780 his first paper, an Inquiry in Regard to the Varying Lustre of Several Stars, was communicated to the Royal Society. This was followed by other papers embodying the results of his observations, and culminating in an inquiry whether there was any relation between the recurrence of sun-spots and the variability of seasons on the earth. The appearance of a white spot near each pole of the planet Mars led to investigation which caused him to conclude that the climate of that planet closely resembles ours, and that the white patches were snow, a conclusion since confirmed by other investigators. In 1781 he discovered a planet to which he gave the name of Georgium Sidus (the Georgian Star), afterward called Herschel, and now called Uranus. In 1782 Herschel was invited by George III. to Windsor, and was appointed the King's private astronomer, with a salary of £200 a year, and an additional £50 for the assistance of his sister. They established themselves at Slough, where they continued their investigations. From 1784 to 1818 he addressed a series of remarkable papers to the Royal Society, on the stars of the Milky Way and their attendant planets, and on the nebulous masses from the condensation of which he conceived the stellar universe to have been formed. Besides pursuing his investigations, he constructed a grand reflecting telescope, which he completed in August, 1789, through which he could see Saturn with six of its satellites, and through which he soon afterward discovered the seventh. The eighth and the Saturnian ring escaped him. His sister, Caroline Lucretia Herschel, was born at Hanover, March 16, 1750; died there, January 9, 1848. She resided at Hanover, her birth-place, until her twenty-second year, when she went to England, joining her brother at Bath, to whom she gave great assistance, not only acting as his amanuensis, but frequently performing the long and complicated calculations involved in his investigations. HERSCHEL'S MIRRORS. My brother applied himself to perfect his mirrors, erecting in his garden a stand for his twenty-foot telescope; many trials were necessary before the required motions for such an unwieldly machine could be contrived. Many attempts were made by way of experiment upon a mirror before an intended thirty-foot telescope could be completed, for which, between whiles (not interrupting the observations with seven, ten, and twenty foot, and writing papers for both the Royal and Bath Philosophical Societies), gauges, shapes, weight, etc., of the mirror were calculated, and trials of the composition of the metal were made. In short, I saw nothing else and heard nothing else talked of but about these things when my brothers were together. Alex was always very alert, assisting when anything new was going forward, but he wanted perseverance, and never liked to confine himself at home for many hours together. And so it happened that my brother William was obliged to make trial of my abilities in copying for him catalogues, tables, etc., and sometimes whole papers which were lent him for his perusal. Among them was one by Mr. Michel and a catalogue of Christian Mayer in Latin, which kept me employed when my brother was at the telescope at night. When I found that a hand was sometimes wanted when any particular measures were to be made with the lamp micrometer, etc., or a fire to be kept up, or a dish of coffee necessary during a long night's watching, I undertook with pleasure what others might have thought a hardship. . The mirror for the thirty-foot reflector was never out of his mind, and if a minute could be spared in going from one scholar to another, or giving one the slip, he called at home to see how the men went on with the furnace, which was built in a room below, even with the garden. The mirror was to be cast in a mould of loam prepared from horse-dung, of which an immense quantity was to be pounded in a mortar and sifted through a fine sieve. It was an endless piece of work, and served me for many an hour's exercise; and Alex frequently took his turn at it, for we were all eager to do something toward the great undertaking. Even Sir William Watson would sometimes take the pestle from me when he found me in the work-room, where he expected to find his friends, in whose concerns he took so much interest that he felt disappointed at not being allowed to pay for the metal. But I do not think my brother ever accepted pecuniary assistance from any one of his friends; and on this occasion he declined the offer by saying it was paid for already.- From Caroline Herschel's Memoirs. ERTZ, HENRIK, a Danish dramatist and poet; born of Jewish parents at Copenhagen, August 25, 1798; died there, February 25, 1870. He studied law, but had scarcely passed his examination when he gave himself to literature. His first comedy appeared anonymously, in 1827. He afterward traveled in Germany, Italy, and France. He left in all thirty-six works, among which are The Moving Day (1828); Cupid's Master Strokes (1830); The Plumage of the Swan (1841); comedies, in which the characters are traced with decided ability. He also wrote a didactic poem, On Nature and Art (1832), and Tyrfing, a poem, in 1840. In 1836 his comedy The Savings Bank enjoyed a large share of public favor. The next year he further increased his popularity by the production of Svend Dyring's House, a beautiful and original piece, which held an impor tant place on the stage for many years. In fact this piece and King René's Daughter are works which may be regarded as landmarks in Danish literature and stamp their author as a troubadour of the fiery and sensuous school of romance. As a lyric poet he has all the color and passion of Keats, and his style is grace itself. He has little or no local Scandinavian coloring, and succeeds best when he is describing the scenery or emotions of the glowing South. King René's Daughter, a lyrical drama, produced in 1845, is regarded as his masterpiece. Its whole action is comprised between noon and sunset of a single day. In the following scene Iolanthe, the King's blind daughter, is represented as sleeping in a garden under the influence of a talisman. KING RENE'S DAUGHTER. [Characters: KING RENÉ; IOLANTHE, his blind daughter; EBN JAHIA, a physician; TRISTAN; ALMERIK, a messenger from the King; MARTHA and BERTRAND, attendants of IOLANTHE.] Almerik. And so she lacks for naught, and is content If but some stranger on occasion come? Of all the wealth the world to us presents, Martha. That is a point J On which 'tis not so easy to reply; It may be she suppresses many a thought. |