Page:EB1911 - Volume 08.djvu/413

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in Munich, on the 14th of January 1890, at the age of ninety-one. Even in articulo mortis he refused to receive the sacraments from the parish priest at the cost of submission, but the last offices were performed by his friend Professor Friedrich.

In addition to the works referred to in the foregoing sketch, we may

mention The Eucharist in the First Three Centuries (Mainz, 1826); a Church History (1836, Eng. trans. 1840); Hippolytus and Callistus (1854, Eng. trans., 1876); First Age of Christianity (1860); Lectures on the Reunion of the Churches; The Vatican Decrees; Studies in European History (tr. M. Warre, 1890); Miscellaneous Addresses (tr. M. Warre, 1894).

See Life by J. Friedrich (3 vols. 1899-1901); obituary notice in The Times, 11th January 1890; L. von Kobell, Conversations of

Dr Döllinger (tr. by K. Gould, 1892).
 (J. J. L.*) 

DOLLOND, JOHN (1706-1761), English optician, was the son of a Huguenot refugee, a silk-weaver at Spitalfields, London, where he was born on the 10th of June 1706. He followed his father's trade, but found time to acquire a knowledge of Latin, Greek, mathematics, physics, anatomy and other subjects. In 1752 he abandoned silk-weaving and joined his eldest son, Peter Dollond (1730-1820), who in 1750 had started in business as a maker of optical instruments. His reputation grew rapidly, and in 1761 he was appointed optician to the king. In 1758 he published an “Account of some experiments concerning the different refrangibility of light” (Phil. Trans., 1758), describing the experiments that led him to the achievement with which his name is specially associated, the discovery of a means of constructing achromatic lenses by the combination of crown and flint glasses. Leonhard Euler in 1747 had suggested that achromatism might be obtained by the combination of glass and water lenses. Relying on statements made by Sir Isaac Newton, Dollond disputed this possibility (Phil. Trans., 1753), but subsequently, after the Swedish physicist, Samuel Klingenstjerna (1698-1765), had pointed out that Newton's law of dispersion did not harmonize with certain observed facts, he began experiments to settle the question. Early in 1757 he succeeded in producing refraction without colour by the aid of glass and water lenses, and a few months later he made a successful attempt to get the same result by a combination of glasses of different qualities (see Telescope). For this achievement the Royal Society awarded him the Copley medal in 1758, and three years later elected him one of its fellows. Dollond also published two papers on apparatus for measuring small angles (Phil. Trans., 1753, 1754). He died in London, of apoplexy, on the 30th of November 1761.

An account of his life, privately printed, was written by the Rev.

John Kelly (1750-1809), the Manx scholar, who married one of his


DOLMAN (from Turk. dōlāmān), originally a long and loose garment left unfastened in front, and with narrow sleeves. It is worn generally by the Turks, and is not unlike a cassock in shape. The name was given to the uniform jacket, worn by hussars, and slung from the shoulders with the sleeves hanging loose; and it is also used for a similar garment worn by ladies, with wide cape-like arrangements instead of sleeves.

DOLNJA TUZLA, or Donji Soli, the capital of the Dolnja Tuzla district, in Bosnia, beautifully situated on the Jala or Julla, a small stream flowing into the Spreča, which joins the Bosna at Doboj, 39 m. W.N.W.; and on a branch railway from Doboj. Pop. (1895) 10,227; almost all, including a permanent colony of gipsies, being Moslems. Dolnja Tuzla is the seat of a district court and an Orthodox bishop; with several churches, many mosques, a hospital, gymnasium and commercial school. Besides large alkali works, it has a vigorous trade in grain, livestock, timber and coal, from the surrounding hills, where there is a colony of Hungarian miners; while the salt springs, owned by the state both at Dolnja, or Lower, and Gornja, or Upper Tuzla, 6 m. E., are without a rival in the Balkan Peninsula.

Dolnja Tuzla was called by the Romans Ad Salinas. Constantine Porphyrogenitus mentions it, in the 10th century, as Salenes; in other medieval documents it appears as Sou, Sow or Soli. Its modern name is derived from the Turkish tuz, “salt.” In 1690 the Austrians routed the Turks at Gornja Tuzla, and removed the Franciscan friars, with about 3000 other Roman Catholics, into Slavonia.

DOLOMIEU, DÉODAT GUY SILVAIN TANCRÈDE GRATET DE (1750-1801), French geologist and mineralogist, was born at Dolomieu, near Tour-du-Pin, in the department of Isère in France, on the 24th of June 1750. He was admitted in his infancy a member of the Order of Malta. In his nineteenth year he quarrelled with a knight of the galley on which he was serving, and in the duel that ensued killed him. He was condemned to death for his crime, but in consideration of his youth the grand master granted him a pardon, which, at the instance of Cardinal Torrigiani, was confirmed by Pope Clement XIII., and after nine months' imprisonment he was set at liberty. Throughout that period he had solaced himself with the study of the physical sciences, and during his subsequent residence at Metz he continued to devote himself to them. In 1775 he published his Recherches sur la pesanteur des corps à differentes distances du centre de la terre, and two Italian translations of mineralogical treatises by A. F. Cronstedt (1702-1765) and T. O. Bergman (1735-1784). These works gained for him the honour of election as a corresponding member of the Académie des Sciences at Paris. To obtain leisure to follow his favourite pursuits Dolomieu now threw up the commission which, since the age of fifteen, he had held in the carabineers, and in 1777 he accompanied the bailli (afterwards Cardinal L. R. E.) de Rohan to Portugal. In the following year he visited Spain, and in 1780 and 1781 Sicily and the adjacent islands. Two months of the year 1782 were spent in examining the geological structure of the Pyrenees, and in 1783 the earthquake of Calabria induced him to go to Italy. The scientific results of these excursions are given in his Voyage aux îles de Lipari (1783); Mémoire sur le tremblement de terre de la Calabre (1784); Mémoire sur les îles Ponces, et catalogue raisonné des produits de l'Etna (1788) and other works. In 1789 and 1790 he busied himself with an examination of the Alps, his observations on which form the subject of numerous memoirs published in the Journal de physique. The mineral dolomite, which was named after him, was described by Dolomieu in 1791. He returned to France in that year, bringing with him rich collections of minerals. On the 14th of September 1792 the duc de la Rochefoucauld, with whom he had been for twenty years on terms of the closest intimacy, was assassinated at Forges, and Dolomieu retired with the widow and daughter of the duke to their estate of Roche Guyon, where he wrote several important scientific papers. The events of the 9th Thermidor (July 27, 1794) having restored the country to some tranquillity, Dolomieu recommenced his geological tours, and visited various parts of France with which he had been previously unacquainted. He was in 1796 appointed engineer and professor at the school of mines, and was chosen a member of the Institute at the time of its formation. At the end of 1797 he joined the scientific staff which in 1798 accompanied Bonaparte's expedition to Egypt. He had proceeded up the Nile as far as Cairo when ill-health made his return to Europe necessary, and on the 7th of March 1799 he set sail from Alexandria. His ship proving unseaworthy put into Taranto, and as Naples was then at war with France, all the French passengers were made prisoners. On the 22nd of May they were carried by ship to Messina, whence, with the exception of Dolomieu, they embarked for the coast of France. Dolomieu had been an object of the hatred of the Neapolitan court since 1783, when he revealed to the grand master of his order its designs against Malta, and the calumnies of his enemies on that island served now as a pretext for his detention. He was confined in a pestilential dungeon, where, clothed in rags, and having nothing but a little straw for a bed, he languished during twenty-one months. Dolomieu, however, did not abandon himself to despair. Deprived of writing materials, he made a piece of wood his pen, and with the smoke of his lamp for ink he wrote upon the margins of a Bible, the only book he still possessed, his treatise Sur la philosophie minéralogique et sur l'espèce minérale (1801). Friends entreated, but in vain, for his liberty; it was with difficulty that they succeeded in furnishing him with a little assistance, and it was only by virtue of a special clause in the treaty between France and Naples that, on the 15th of March 1801, he was released. On his arrival in France he commenced the duties of the chair of mineralogy at the museum