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566 OBSERVANTS OBSERVATORY Dublin. He was tried at Clonmel on a charge of high treason, convicted, and sentenced to death (Oct. 9) ; but the sentence was com- muted to transportation for life. In July, 1849, he embarked for Tasmania, where he remained till 1856, when the pardon accorded to the Irish agitators of 1848 enabled him to return home. In 1859 he visited the United States, and after his return took no prominent part in public affairs. When the civil war broke out in the United States in 1861, he published a manifesto expressing his strong sympathy for the se- ceding states, and counselling his countrymen not to commit themselves in favor of the Union. OBSERVANTS. See FKANCISCANS. OBSERVATORY, a place for making observa- tions upon any great class of natural phenom- ena. Observatories are of three kinds : mag- netical, for observing the phenomena of ter- restrial magnetism ; meteorological, for obser- ving the phenomena of atmospheric changes; and astronomical, for observations of the heav- enly bodies. In an astronomical observatory it is necessary that there should be a fixed sup- port for the instruments, and exemption from tremors and atmospheric disturbances. To se- cure the first, the instruments are to be firmly planted on stone piers, completely isolated from all other bases of support and from the build- ing. To secure the second, a situation is to be chosen secluded from ways of travel and busi- ness. It is important that the locality be dry, of equable temperature, as nearly exempt as possible from fogs, clouds, &c., and screened from high winds so far as is consistent with a free view of the horizon. The instruments on which exact astronomy is founded are the transit and its clock for obtaining and keeping exact time, the transit circle, and the mural circle for measuring the meridian distances of stars from the zenith. There are also several other principal instruments, viz. : the equato- rial telescope, which can be directed to any part of the heavens ; the heliometer, for taking the most difficult micrometric measurements ; and the altitude and azimuth circle, for determining these elements of a star's place. Every well equipped observatory has also a variety of lesser instruments. Barometers, psychrometers, ther- mometers, chronometers, &c., are important accessories. Of the more ancient instruments the zenith sector and the mural quadrant are no longer in use, and the transit circle is grad- ually replacing the mural circle in all the lead- ing observatories. The American method of recording observations by means of electro- magnetism introduced a novel and elegant kind of apparatus among the equipments of the observatory, and greatly increased the efficien- cy of the labors of the practical observer. The first epoch of modern practical astrono- my begins with the labors of Tycho Brahe at his castle of Uranienborg near Copenhagen (1580). But Uranienborg has disappeared; hardly its site is known. Of the great astro- nomical institutions extant, the observatory of Paris is the oldest. Built in 1667-'71 by order of Louis XIV., and designed by Claude Per- rault, the famous architect of the Louvre, it was an edifice of great magnificence, but ill adapted to the purpose for which it was in- tended. Domenico Cassini, an Italian, was its first director. Here Picard labored from 1673 till his death about 1682; and in recent times this institution attained a high degree of effi- ciency under the directorship of Arago. It is now directed by Leverrier. The royal observa- tory at Greenwich began operations in 1676, with Flamsteed for astronomer royal. Sir G. B. Airy, the present incumbent, has held the office since 1835. The Tusculan obser- vatory in Copenhagen was built in 1704, for Roemer, the discoverer of the velocity of light. Peter the Great caused an observatory to be erected in 1725 at his capital, and the French astronomer De Lisle was invited to be its director. The emperor Nicholas built another in 1839 at Pulkova, a small town 10 m. S. of St. Petersburg, on a scale of unprecedented magnificence. The cost was about $500,000, and $50,000 is annually appropriated from the imperial treasury for its maintenance. It is the best endowed and the most perfectly or- ganized of all continental observatories. At- tached to it are a very fine library and work- shops for repairs and alterations in the instru- ments. Wilhelm Struve, its first director, has given a complete description of this establish- ment {Description de V observatoire astrono- mique central de Pullcowa, 2 vols. fol., St. Pe- tersburg, 1845). It is at present under the management of his son, Otto Struve. The ob- servatory at Dorpat (founded about 1811) was the scene of the elder Struve's researches in sidereal astronomy, and of the no less useful labors and speculations of Madler in the same department. The observatory of Konigsberg (1813), under Bessel, became second to none during the present century for its contributions toward the improvement of every branch of astronomy. The observatory of Berlin (about 1834) is important on account of the labors of Encke. Here the planet Neptune was first seen by Dr. Galle, Sept. 23, 1846. Of the British public establishments of the first class, there are, besides that at Greenwich already mentioned, the Radcliffe observatory at Oxford (1774), under the directorship of the Rev. R. Main since 1859 ; that at the cape of Good Hope (1821), memorable for the successful re- searches of Prof. Henderson of Edinburgh in determining the parallax of Alpha Centauri, and which was under the direction of Sir R. Maclear from 1833 to 1870, when he was suc- ceeded by Mr. E. Stone of Greenwich ; that at Cambridge (1824), under Prof. Adams, as suc- cessor to Prof. Challis ; the royal observatory of Edinburgh (about 1825), under Prof. Piazzi Smyth since 1844 ; and the royal observatory of Dublin (1774) under Mr. R. S. Bale. The university of Oxford has decided (1875) to found a second observatory. There are many