| 单词 | mural arc |
| 释义 | > as lemmasmural arc 4. Astronomy. Designating or relating to a wall or walled arch set in the plane of the meridian for the alignment of a large quadrant, telescope, etc.; frequently in mural arc, mural circle. Also: designating an instrument fixed to such a wall. Now historical.Such instruments were superseded by the meridian circle or transit circle. ΘΚΠ the world > the universe > cosmology > science of observation > astronomical instruments > measuring altitude > [noun] > mural arch mural arc1786 mural circle1833 1674 R. Hooke Animadversions Machina Cœlestis 32 Let there be made a very large mural Quadrant. 1722 Philos. Trans. 1720–21 (Royal Soc.) 31 2 This Tube he [sc. Cassini] firmly fix'd to the Plain of a Mural Arch, which had been for above 30 Years immoveably cemented to the Wall of the Royal Observatory. 1728 E. Chambers Cycl. (at cited word) Tycho de Brahe was the first who used a Mural-Arch in his Observations. 1739 Philos. Trans. 1737–8 (Royal Soc.) 40 45 Two mural Quadrants of Mr. Grahams's Make. 1769 Philos. Trans. 1768 (Royal Soc.) 58 54 The surface of the water wherein the ball of the plumb-line hung, for rectifying the position of my mural quadrant, was continually freezing. 1786 Philos. Trans. (Royal Soc.) 76 5 In the year 1689, Mr. Flamsteed compleated his mural arc at Greenwich. 1812 R. Woodhouse Elem. Treat. Astron. vi. 25 When the quadrant is fixed to the side of a vertical wall in the plane of the meridian, it is called a mural quadrant. 1833 Mem. Royal Astron. Soc. 5 325 Not long after the mural circle was fixed at the Cape Observatory it was rumoured that the Astronomer..was dissatisfied with its performance. 1861 G. F. Chambers Handbk. Descr. Astron. viii. v. 356 The Mural Circle consists of a graduated circle furnished with a suitable telescope, and very firmly affixed to a wall (murus) in the plane of the meridian. 1911 Encycl. Brit. XXVII. 311/2 Troughton was dissatisfied with this form of instrument [sc. the transit circle], which a few years afterwards was brought to great perfection.., and designed the mural circle in its place. 1946 Nature 14 Dec. 858/2 A large mural quadrant, which was his own invention, of 6¾ ft. radius. 1994 J. North Fontana Hist. Astron. & Cosmol. viii. 187 He [sc. al-Battānī] introduced material on instruments—a sundial with seasonal hours, a new type of armillary, a mural quadrant. < as lemmas |
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