in fortification, turfs, or pieces of fresh earth covered with grass, cut in form of a wedge, about a foot long, and half a foot thick, to line or face the outside of works made of earth, to keep them up, and prevent their mouldering.

GEOCENTRIC PLACE of a planet, is the place where it appears to us from the earth; or it is a point in the ecliptic, to which a planet, seen from the earth, is referred.

GEOCENTRIC Latitude of a planet, is its latitude as seen from the earth, or the inclination of a line connecting the planet and the earth to the plane of the earth's (or true) ecliptic: Or it is the angle which the said line (connecting the planet and the earth) makes with a line drawn to meet a perpendicular let fall from the planet to the plane of the ecliptic.

GEOCENTRIC Longitude of a planet, is the distance measured on the ecliptic, in the order of the signs, between the geocentric place and the first point of Aries.

GEOMETRICAL Method of the Ancients. The ancients established the higher parts of their geometry on the same principles as the elements of that science, by demonstrations of the same kind: and they were careful not to suppose anything done, till by a previous problem they had shown that it could be done by actually performing it. Much less did they suppose anything to be done that cannot be conceived; such as a line or series to be actually continued to infinity, or a magnitude diminished till it become infinitely less than what it is. The elements into which they resolved magnitudes were finite, and such as might be conceived to be real. Unbounded liberties have of late been introduced; by which geometry, which ought to be perfectly clear, is filled with mysteries.

GEOMETRICAL Solution of a problem, is when the problem is directly resolved according to the strict rules and principles of geometry, and by lines that are truly geometrical. This exposition is used in contradiction to an arithmetical, or mechanical, or instrumental solution, the problem being resolved only by a ruler and compasses.

The same term is likewise used in opposition to all indirect and inadequate kinds of solutions, as by approximation, infinite series, &c. So we have no geometrical way of finding the quadrature of the circle, the duplicature of the cube, or two mean proportions, though there are mechanical ways, and others, by infinite series, &c.