| 释义 |
equatorial, a. and n.|iːkwəˈtɔərɪəl, ɛkwə-|
Also 7–8 æquatorial, 8–9 equatoreal.
[f. L. æquātor (see prec.) + -ial; in Fr. équatorial.]
A. adj.
1. a. Of or pertaining to the equator; situated or existing on or about the equator.
1713Derham Phys.-Theol. ii. i. note 1 (R.), A prolate sphæroid, making the polar about 34 miles shorter than the equatorial diameter. 1789Herschel Saturn in Phil. Trans. LXXX. 16 The arrangement of the belts..has always followed the direction of the ring, which is what I have called being equatorial. 1794G. Adams Nat. & Exper. Philos. III. xxxii. 334 Their surfaces will be higher..in the equatoreal, than in the polar regions. 1860Maury Phys. Geog. Sea v. §296 Panama is in the region of equatorial calms. 1870Yeats Nat. Hist. Comm. 65 Equatorial grains are maize and rice.
b. Pertaining to the ‘equator’ of a magnet, or of any spherical or spheroidal body.
1664Power Exp. Philos. iii. 168 Those aequatorial parts of the Magnet, which before respected the East. 1837Brewster Magnet. 268 The middle of a copper wire..was applied to the equatorial groove. 1861J. R. Greene Man. Anim. Kingd., Cœlent. 227 In Cestum..these [a pair of symmetrical tentacles] do not..issue from the equatorial region, thence turning away from the mouth.
c. Pertaining to the equator of a balloon (cf. prec. 3 d).
1838M. Mason Aeronautica 30 In shape it [sc. a balloon] somewhat resembles a pear; its upright or polar diameter exceeding the transverse or equatorial by about one-sixth.
2. equatorial instrument or equatorial telescope: an apparatus consisting essentially of a telescope attached by an arm to an axle revolving in a direction parallel to the plane of the equator. By a uniform motion given to this axle (in large instruments by clockwork) the telescope follows the diurnal apparent motion of any point in the heavens to which it is directed. equatorial circle: a graduated circle (otherwise called hour-circle, right-ascension-circle) revolving in a plane parallel to the equator, forming part of the equatorial instrument.
1791Jefferson in Harper's Mag. (1885) Mar. 535/2 He is to pay for equatorial instrument. 1793Sir G. Shuckburgh Equator. Instr. in Phil. Trans. LXXXIII. 72 The idea of an equatorial telescope was again renewed by three several artists in this kingdom. 1868Airy Pop. Astron. ii. 39 For causing the Equatoreal instrument to revolve uniformly.
3. Biol. (Cf. prec. 3 e.) equatorial plate [tr. F. plaque équatoriale (E. van Beneden 1875, in Bull. de l'Acad. R. d. Sci. de Belg. (Classe des Sciences) 2me Sér. XL. 733)], in mitosis and meiosis, the position occupied by the chromosomes when arranged in the equatorial plane of the spindle during metaphase.
1887A. C. Haddon Introd. Study Embryol. ii. 19 At the stage when the chromatin is equatorially situated (the ‘equatorial plate’, which is the equivalent of the wreath and aster stage), the achromatin forms a well-marked spindle-shaped bundle of fibres. 1896E. B. Wilson Cell ii. 49 The chromosomes group themselves in a plane passing through the equator of the spindle, and thus form what is known as the equatorial plate. 1913J. W. Jenkinson Vertebr. Embryol. iii. 40 The plane at right angles to the axis and including the centre of the egg is equatorial. 1952A. Hughes Mitotic Cycle iv. 116 During metaphase the chromosomes move from random positions into the ‘equatorial plate’. 1958C. P. Swanson Cytol. & Cytogenetics iii. 52 The spindle..serves to bring the chromosomes onto the metaphase, or equatorial, plate. 1960L. Picken Organization of Cells x. 501 Either before fertilization or at the eight-cell stage, an equatorial separation of the two halves of the egg gives rise to qualitatively different larvae.
B. n.
a. = equatorial instrument: see A. 2.
1793Sir G. Shuckburgh Equator. Instr. in Phil. Trans. LXXXIII. 84 The equatorial is a machine calculated to observe the heavenly bodies in every part of the hemisphere. 1847Whewell Hist. Induct. Sc. vii. vi. §1 (ed. 2) Transit instruments, equatorials, heliometers. 1879Lockyer Elem. Astron. vi. 224 An equatorial.
b. attrib. in equatorial clock, a clock for driving an equatorial.
1884Britten Watch and Clockm. Hand-bk. 66, 102. |