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The representation of the circles of the sphere upon a plane; especially, a representation of the celestial sphere upon a plane with adjustable circles, or other appendages, for showing the position of the heavens, the time of rising and setting of stars, etc., for any given date or hour.

ence, or zero of reckoning, in the heavens, usually the intersection of two or more great circles of the sphere, and named specifically in each case according to the position intended; as, the equinoctial points; the solstitial points; the nodal points; vertical points, etc. See Equinoctial Nodal.

of the fertilizing spermatozoön; but their functions are not fully understood. -- Polar circles (Astron. & Geog.), two circles, each at a distance from a pole of the earth equal to the obliquity of the ecliptic, or about 23º 28', the northern called the arctic circle, and the southern the antarctic circle. -- Polar…

n the surface of a sphere equally distant from every part of the circumference of a great circle; or the point in which a diameter of the sphere perpendicular to the plane of such circle meets the surface. Such a point is called the pole of that circle; as, the pole of the horizon; the pole of the ecliptic; the pole of…

h any line (as that joining two stars) makes with another fixed line, specifically with a circle of declination. -- Double position (Arith.), the method of solving problems by proceeding with each of two assumed numbers, according to the conditions of the problem, and by comparing the difference of the results with th…

no number except itself or unity, as 5, 7, 11. -- Prime vertical (Astron.), the vertical circle which passes through the east and west points of the horizon. -- Prime-vertical dial, a dial in which the shadow is projected on the plane of the prime vertical. -- Prime-vertical transit instrument, a transit instrument…

tal base of the harmony; -- opposed to derivative. Moore (Encyc. of Music). -- Primitive circle (Spherical Projection), the circle cut from the sphere to be projected, by the primitive plane. -- Primitive colors (Paint.), primary colors. See under Color. -- Primitive Fathers (Eccl.), the acknowledged Christian write…

nt of sight is at the center, and the plane of projection passes through one of the polar circles. -- Powder of projection (Alchemy.), a certain powder cast into a crucible or other vessel containing prepared metal or other matter which is to be thereby transmuted into gold. -- Projection of a point on a plane (Descr…

f the larvæ of Lepidoptera, sawflies, and some other insects. Those of Lepidoptera have a circle of hooks. Called also proped, propleg, and falseleg.

strict; overscrupulous; rigid; -- often used by way of reproach or contempt. Paritanical circles, from which plays and novels were strictly excluded. Macaulay. He had all the puritanic traits, both good and evil. Hawthorne.

To rise in circles, ripples, or undulations; to curl; to mantle. thin winding breath which purled up to the sky. Shak.

The quarter of a circle, or of the circumference of a circle, an arc of 90º, or one subtending a right angle at the center.

Of or pertaining to a quadrant; also, included in the fourth part of a circle; as, quadrantal space. Quadrantal triangle, a spherical triangle having one side equal to a quadrant or arc of 90º. -- Quadrantal versor, a versor that expresses rotation through one right angle.

of the heavenly bodies in which they are distant from each other 90º, or the quarter of a circle; quartile. See the Note under Aspect, 6.

f a square having the same area as some given curvilinear figure; as, the quadrature of a circle; the operation of finding an expression for the area of a figure bounded wholly or in part by a curved line, as by a curve, two ordinates, and the axis of abscissas.

l phyllotaxy (Bot.), an arrangement of five leaves in a spiral, each leaf two fifths of a circle from the next.

An arc of a circle which is equal to the radius, or the angle measured by such an arc.

o a radix or root; as, a radical quantity; a radical sign. See below. Radical axis of two circles. (Geom.) See under Axis. -- Radical pitch, the pitch or tone with which the utterance of a syllable begins. Rush. -- Radical quantity (Alg.), a quantity to which the radical sign is prefixed; specifically, a quantity whi…

A right line drawn or extending from the center of a circle to the periphery; the semidiameter of a circle or sphere.

ample range extends. Pope. The range and compass of Hammond's knowledge filled the whole circle of the arts. Bp. Fell. A man has not enough range of thought. Addison.