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atise on this science. Astronomical, or Mathematical, geography treats of the earth as a planet, of its shape, its size, its lines of latitude and longitude, its zones, and the phenomena due to to the earth's diurnal and annual motions. -- Physical geography treats of the conformation of the earth's surface, of the di…

that part of geometry which treats of the simple properties of straight lines, circles, plane surface, solids bounded by plane surfaces, the sphere, the cylinder, and the right cone. -- Higher geometry, that pert of geometry which treats of those properties of straight lines, circles, etc., which are less simple in t…

The planet Uranus, so named by its discoverer, Sir W. Herschel.

rranges for, anything, as a book, a machine, etc. [Colloq.] A diligent getter-up of miscellaneous works. W. Irving.

The angle, esp. the least angle, at which a gliding machine or aëroplane will glide to earth by virtue of gravity without applied power.

A construction consisting essentially of one or more aëroplanes for gliding in an inclined path from a height to the ground.

jection (Map Projection), a perspective projection of the surface of a hemisphere upon a plane parallel to the base of the hemisphere, the point of sight being taken in the axis produced beyond the surface of the opposite hemisphere a distance equal to the radius of the sphere into the sine of 45º. -- Globular sailing…

quartz, feldspar, and mica, but having these materials, especially the mica, arranged in planes, so that it breaks rather easily into coarse slabs or flags. Hornblende sometimes takes the place of the mica, and it is then called hornblendic or syenitic gneiss. Similar varieties of related rocks are also called gneiss.…

ere, 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 or dial." Cyc. of Arts & Sciences.…

nstrument for measuring angles, especially the angles of crystals, or the inclination of planes. Contact, or Hand, goniometer, a goniometer having two movable arms (ab, cd), between which (at ab) the faces of the crystals are placed. These arms turn about a fixed point, which is the center of the graduated circle or se…

The rate of ascent or descent; gradient; deviation from a level surface to an inclined plane; -- usually stated as so many feet per mile, or as one foot rise or fall in so many of horizontal distance; as, a heavy grade; a grade of twenty feet per mile, or of 1 in 264.

a whitish, grayish, or flesh-red color. It differs from gneiss in not having the mica in planes, and therefor in being destitute of a schistose structure.

Ground line (Descriptive Geom.), the line of intersection of the horizontal and vertical planes of projection. -- Ground liverwort (Bot.), a flowerless plant with a broad flat forking thallus and the fruit raised on peduncled and radiated receptacles (Marchantia polymorpha). -- Ground mail, in Scotland, the fee paid…

The original sense seems to have been a lane cut through trees. See Grave, v., and cf. Groove.] A smaller group of trees than a forest, and without underwood, planted, or growing naturally as if arranged by art; a wood of small extent.

A thin quadrant, made of brass, wood, etc., showing a stereographic projection on the plane of the equator. By it are found the hour of the day, the sun's azimuth, the altitude of objects in degrees, etc. See Gunter's scale.

y crowning it with ornaments, regularly spaced, like a diminutive battlement. -- Gutter plane, a carpenter's plane with a rounded bottom for planing out gutters. -- Gutter snipe, a neglected boy running at large; a street Arab. [Slang] -- Gutter stick (Printing), one of the pieces of furniture which separate pages in…

Having the planes arranged spirally, so that they incline all to the right (or left) of a vertical line; -- said of certain hemihedral forms.

rotation of the earth, through the tendency of the rotating wheel to preserve a constant plane of rotation, independently of the earth's motion.

An instrument for drawing spiral lines on a plane.

A nonplane curve whose tangents are all equally inclined to a given plane. The common helix is the curve formed by the thread of the ordinary screw. It is distinguished from the spiral, all the convolutions of which are in the plane.