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herical body, solid or hollow; a body whose surface is in every part equidistant from the center; a ball; a sphere.

n, a projection of the circles of the sphere, in which the point of sight is taken at the center of the sphere, and the principal plane is tangent to the surface of the sphere. "The gnomonic projection derives its name from the connection between the methods of describing it and those for the construction of a gnomon o…

) the faces of the crystals are placed. These arms turn about a fixed point, which is the center of the graduated circle or semicircle upon which the angle is read off. -- Reflecting goniometer, an instrument for measuring the angles of crystals by determining through what angular space the crystal must be turned so t…

2. A vehicle used for levelling earth, esp. one with a plow blade suspended from the center, used specifically for grading roads.

, having a thick trunk crowned with a dense tuft of pendulous, grasslike leaves, from the center of which arises a long stem, bearing at its summit a dense flower spike looking somewhat like a large cat-tail. These plants are often called "blackboys" from the large trunks denuded and blackened by fire. They yield two k…

Causing to gravitate; tending to a center. Coleridge.

The tendency of a mass of matter toward a center of attraction; esp., the tendency of a body toward the center of the earth; terrestrial gravitation.

large reflector, transmits the light received from the latter back through a hole in its center to the eyepiece placed behind it. -- Gregorian year, the year as now reckoned according to the Gregorian calendar. Thus, every year, of the current reckoning, which is divisible by 4, except those divisible by 100 aud not…

The act of turning or whirling, as around a fixed center; a circular or spiral motion; motion about an axis; rotation; revolution. The gyrations of an ascending balloon. De Quincey. If a burning coal be nimbly moved round in a circle, with gyrations continually repeated, the whole circle will appear like fire. Sir I. N…

A straight line considered as drawn from a center to an indefinite distance in one direction, the complete ray being the whole line drawn to an indefinite distance in both directions.

That part of an elliptical or many-centered arch which has the shorter radius and immediately adjoins the impost.

ead of a police force; the place from which orders or instructions are issued; hence, the center of authority or order. The brain, which is the headquarters, or office, of intelligence. Collier.

The nearest the middle or center; the part most hidden and within; the inmost or most essential part of any body or system; the source of life and motion in any organization; the chief or vital portion; the center of activity, or of energetic or efficient action; as, the heart of a country, of a tree, etc. Exploits don…

pertaining to the sun's center, or appearing to be seen from it; having, or relating to, the sun as a center; -- opposed to geocentrical. Heliocentric parallax. See under Parallax. -- Heliocentric place, latitude, longitude, etc. (of a heavenly body), the direction, latitude, longitude, etc., of the body as viewed fro…

A half sphere; one half of a sphere or globe, when divided by a plane passing through its center.

und; as, a hollow heart; a hollow friend. Milton. Hollow newel (Arch.), an opening in the center of a winding staircase in place of a newel post, the stairs being supported by the wall; an open newel; also, the stringpiece or rail winding around the well of such a staircase. -- Hollow quoin (Engin.), a pier of stone o…

Having the same center.

A plane parallel to the sensible horizon of a place, and passing through the earth's center; -- called also rational or celestial horizon.

hydrometer consisting of a hollow ball of ivory or metal suspended by a treated from the center of a graduated quadrant, and held in a stream to measure the velocity of the water by the inclination given to the thread; a kind of current gauge.

; -- applied to that action which, in the case of muscular motion, commences in the nerve centers, and excites the muscles to contraction. Opposed to excito-motor.