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A curve of the fourth degree, invented by Pascal. Its polar equation is r = a cos + b.

A spiral whose polar equation is r2th = a; that is, a curve the square of whose radius vector varies inversely as the angle which the radius vector makes with a given line.

A piece of magnetic iron ore possessing polarity like a magnetic needle. See Magnetite.

Having impaired polarity; -- applied to a compass needle. [Colloq.] Like mad, like a mad person; in a furious manner; as, to run like mad. L'Estrange. -- To run mad. (a) To become wild with excitement. (b) To run wildly about under the influence of hydrophobia; to become affected with hydrophobia. -- To run mad after…

h as the mariner's and the surveyor's. -- Magnetic poles, the two points in the opposite polar regions of the earth at which the direction of the dipping needle is vertical. -- Magnetic pyrites. See Pyrrhotite. -- Magnetic storm (Terrestrial Physics), a disturbance of the earth's magnetic force characterized by grea…

ck color and metallic luster. It is readily attracted by a magnet and sometimes possesses polarity, being then called loadstone. It is an important iron ore. Called also magnetic iron.

ncentration. An artificial variety is a derivative of succinic acid, but has no action on polarized light, and thus malic acid is a remarkable case of physical isomerism.

c ferment of saliva and pancreatic juice. It resembles dextrose, but rotates the plane of polarized light further to the right and possesses a lower cupric oxide reducing power.

pproaching slowly nearer to it. It is called also Cynosura, polestar, and by astronomers, Polaris.

differ in this, viz., that they do or do not produce right-handed or left-handed circular polarization of light. -- Optically positive, Optically negative. See under Refraction.

Those who live within a polar circle, whose shadows, during some summer days, will move entirely round, falling toward every point of the compass.

nceived as situated. -- Plane iron, the cutting chisel of a joiner's plane. -- Plane of polarization. (Opt.) See Polarization. -- Plane of projection. (a) The plane on which the projection is made, corresponding to the perspective plane in perspective; -- called also principal plane. (b) (Descriptive Geom.) One of t…

One of the opposite or contrasted parts or directions in which a polar force is manifested; a point of maximum intensity of a force which has two such points, or which has polarity; as, the poles of a magnet; the north pole of a needle.

Polaris, or the north star. See North star, under North.

Wm. Nicol, of Edinburgh, who first proposed it.] (Opt.) An instrument for experiments in polarization, consisting of a rhomb of Iceland spar, which has been bisected obliquely at a certain angle, and the two parts again joined with transparent cement, so that the ordinary image produced by double refraction is thrown…

nes drawn from every point of a figure and meeting the plane of projection obliquely. -- Polar projection, a projection of the sphere in which the point 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 cruc…

Pertaining to, or dependent on, pyroelectricity; receiving electric polarity when heated.

e turns, and to which it serves to refer the successive points of a curve, in a system of polar coördinates. See Coördinate, n.

ting point; a single element of light or heat propagated continuously; as, a solar ray; a polarized ray.

within the rhomb, at other faces, two reflections. It is used to produce a ray circularly polarized from a plane-polarized ray, or the reverse. Nichol.