All circles passing through the Poles of any great circle, intersect it in two places diametrically opposite, and also at right angles; and with respect to the said great circle, they may be called its _Secundaries_. [Sidenote: _Parallel_ or _lesser Circles_.] All circles dividing the sphere into two unequal parts, are called _lesser_ or _parallel Circles_, and are usually denominated by that great circle to which they are parallel. [Sidenote: _Terrestrial Globe._] The Earth being globular, its outward parts, as the several _Countries_, _Seas_, _&c._ are best, and most naturally represented upon the surfaces of a Globe; and when such a body has the outward parts of the Earth and Sea delineated upon its surface, and placed in their natural order and situation, it is called a _Terrestrial Globe_. [Sidenote: _Celestial Globe._] The Celestial Bodies appear to us as if they were all placed in the same concave sphere, therefore astronomers place the Stars according to their respective situations and magnitudes, and also the images of the constellations, upon the external surface of a Globe; for it answers the same purposes as if they were placed within a concave sphere, if we suppose the Globe to be transparent, and the eye placed in the center. A Globe having the Stars placed upon its surface, as above described, is called a _Celestial Globe_. These Globes are both placed in frames, with other appurtenances, as shall be described in a proper place. [Sidenote: The principal use of the Globes.] The principal uses of the Globes (besides their serving as _Maps_, to distinguish the outward parts of the Earth, and the situations of the fixed Stars) is to explain and resolve the phænomena arising from the diurnal motion of the Earth round its Axis. [Sidenote: There will be the same prospect of the fixed Stars whether the spectator be placed on the Earth, or in the Sun.]