Hadley's quadrant
Quadrant Quad"rant, n. [L. quadrans, -antis, a fourth part, a fourth of a whole, fr. quattuor four: cf. F. quadrant, cadran. See {Four}, and cf. {Cadrans}.] 1. The fourth part; the quarter. [Obs.] --Sir T. Browne. [1913 Webster]

2. (Geom.) The quarter of a circle, or of the circumference of a circle, an arc of 90[deg], or one subtending a right angle at the center. [1913 Webster]

3. (Anal. (Geom.) One of the four parts into which a plane is divided by the co["o]rdinate axes. The upper right-hand part is the first quadrant; the upper left-hand part the second; the lower left-hand part the third; and the lower right-hand part the fourth quadrant. [1913 Webster]

4. An instrument for measuring altitudes, variously constructed and mounted for different specific uses in astronomy, surveying, gunnery, etc., consisting commonly of a graduated arc of 90[deg], with an index or vernier, and either plain or telescopic sights, and usually having a plumb line or spirit level for fixing the vertical or horizontal direction. [1913 Webster]

{Gunner's quadrant}, an instrument consisting of a graduated limb, with a plumb line or spirit level, and an arm by which it is applied to a cannon or mortar in adjusting it to the elevation required for attaining the desired range.

{Gunter's quadrant}. See {Gunter's quadrant}, in the Vocabulary.

{Hadley's quadrant}, a hand instrument used chiefly at sea to measure the altitude of the sun or other celestial body in ascertaining the vessel's position. It consists of a frame in the form of an octant having a graduated scale upon its arc, and an index arm, or alidade pivoted at its apex. Mirrors, called the index glass and the horizon glass, are fixed one upon the index arm and the other upon one side of the frame, respectively. When the instrument is held upright, the index arm may be swung so that the index glass will reflect an image of the sun upon the horizon glass, and when the reflected image of the sun coincides, to the observer's eye, with the horizon as seen directly through an opening at the side of the horizon glass, the index shows the sun's altitude upon the scale; -- more properly, but less commonly, called an octant.

{Quadrant of altitude}, an appendage of the artificial globe, consisting of a slip of brass of the length of a quadrant of one of the great circles of the globe, and graduated. It may be fitted to the meridian, and being movable round to all points of the horizon, serves as a scale in measuring altitudes, azimuths, etc. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

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  • Gunner's quadrant — Quadrant Quad rant, n. [L. quadrans, antis, a fourth part, a fourth of a whole, fr. quattuor four: cf. F. quadrant, cadran. See {Four}, and cf. {Cadrans}.] 1. The fourth part; the quarter. [Obs.] Sir T. Browne. [1913 Webster] 2. (Geom.) The… …   The Collaborative International Dictionary of English

  • Gunter's quadrant — Quadrant Quad rant, n. [L. quadrans, antis, a fourth part, a fourth of a whole, fr. quattuor four: cf. F. quadrant, cadran. See {Four}, and cf. {Cadrans}.] 1. The fourth part; the quarter. [Obs.] Sir T. Browne. [1913 Webster] 2. (Geom.) The… …   The Collaborative International Dictionary of English

  • Elton's quadrant — An Elton s quadrant is a derivative of the Davis quadrant. It adds an index arm and artificial horizon to the instrument. It was invented by John Elton a sea captain who patentedhis design in 1728Bennett, Jim, Catadioptrics and commerce in… …   Wikipedia

  • Quadrant — Quad rant, n. [L. quadrans, antis, a fourth part, a fourth of a whole, fr. quattuor four: cf. F. quadrant, cadran. See {Four}, and cf. {Cadrans}.] 1. The fourth part; the quarter. [Obs.] Sir T. Browne. [1913 Webster] 2. (Geom.) The quarter of a… …   The Collaborative International Dictionary of English

  • Quadrant of altitude — Quadrant Quad rant, n. [L. quadrans, antis, a fourth part, a fourth of a whole, fr. quattuor four: cf. F. quadrant, cadran. See {Four}, and cf. {Cadrans}.] 1. The fourth part; the quarter. [Obs.] Sir T. Browne. [1913 Webster] 2. (Geom.) The… …   The Collaborative International Dictionary of English

  • Hadley [1] — Hadley (spr. Hädli), John, früher Instrumentenmacher, Freund des Astronomen Halley, später Vicepräsident der königlichen Societät in London, st. 1744; er verfertigte das erste größere Spiegelteleskop u. erfand 1731 den nach ihm benannten… …   Pierer's Universal-Lexikon

  • Hadley, John — ▪ British mathematician born April 16, 1682, Hertfordshire, England died February 14, 1744, East Barnet, Hertfordshire       British mathematician and inventor who improved the reflecting telescope, producing the first such instrument of… …   Universalium

  • Hadley Upland — (coord|68|29|S|66|24|W|) is a triangular shaped remnant plateau with an undulating surface (1,500 1,900 m) in southern Graham Land. It is bounded by Windy Valley and the Martin, Gibbs and Lammers Glaciers. The existence of this upland was known… …   Wikipedia

  • Quadrant (instrument) — Pour les articles homonymes, voir Quadrant. Le quadrant mobile d Augustin Stark (1815). Le quadrant est un ancien instrument de navigation qui servait à faire le point sur sa position en …   Wikipédia en Français

  • Isaac Newton's early life and achievements — IsaacNewtonSegmentsThe following article is part of an in depth biography of Sir Isaac Newton, the English mathematician and scientist, author of the Principia .ChildhoodSir Isaac Newton was born on December 25, 1642 [ OS: 25 December 1642] in… …   Wikipedia

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