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Lathe n.

1. A granary; a barn. [Obs.]

2. Mach. A machine for turning, that is, for shaping articles of wood, metal, or other material, by causing them to revolve while acted upon by a cutting tool.

3. The movable swing frame of a loom, carrying the reed for separating the warp threads and beating up the weft; -- called also lay and batten.

**Blanchard lathe**, a lathe for turning irregular forms after a given pattern, as lasts, gunstocks, and the like.

**Drill lathe**, *or* **Speed lathe**, a small lathe which, from its high speed, is adapted for drilling; a hand lathe.

**Engine lathe**, a turning lathe in which the cutting tool has an automatic feed; -- used chiefly for turning and boring metals, cutting screws, etc.

**Foot lathe**, a lathe which is driven by a treadle worked by the foot.

**Geometric lathe**. See under Geometric

**Hand lathe**, a lathe operated by hand; a power turning lathe without an automatic feed for the tool.

**Slide lathe**, an engine lathe.

**Throw lathe**, a small lathe worked by one hand, while the cutting tool is held in the other.

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Ge·o·met·ric Ge·o·met·ric·al a.

1. Pertaining to, or according to the rules or principles of, geometry; determined by geometry; as, a geometrical solution of a problem.

Note: ☞ __Geometric__ is often used, as opposed to __algebraic__, to include processes or solutions in which the propositions or principles of geometry are made use of rather than those of algebra.

Note: ☞ __Geometrical__ is often used in a limited or strictly technical sense, as opposed to __mechanical__; thus, a construction or solution is __geometrical__ which can be made by ruler and compasses, *i. e.*, by means of right lines and circles. Every construction or solution which requires any other curve, or such motion of a line or circle as would generate any other curve, is not __geometrical__, but __mechanical__. By another distinction, a __geometrical__ solution is one obtained by the rules of geometry, or processes of analysis, and hence is exact; while a __mechanical__ solution is one obtained by trial, by actual measurements, with instruments, etc., and is only approximate and empirical.

**Geometrical curve**. Same as Algebraic curve; -- so called because their different points may be constructed by the operations of elementary geometry.

**Geometric lathe**, an instrument for engraving bank notes, etc., with complicated patterns of interlacing lines; -- called also cycloidal engine.

**Geometrical pace**, a measure of five feet.

**Geometric pen**, an instrument for drawing geometric curves, in which the movements of a pen or pencil attached to a revolving arm of adjustable length may be indefinitely varied by changing the toothed wheels which give motion to the arm.

**Geometrical plane** Persp., the same as Ground plane .

**Geometrical progression**, **proportion**, **ratio**. See under Progression, Proportion and Ratio.

**Geometrical radius**, in gearing, the radius of the pitch circle of a cogwheel. --*Knight.*

**Geometric spider** Zool., one of many species of spiders, which spin a geometrical web. They mostly belong to Epeira and allied genera, as the garden spider. See Garden spider.

**Geometric square**, a portable instrument in the form of a square frame for ascertaining distances and heights by measuring angles.

**Geometrical staircase**, one in which the stairs are supported by the wall at one end only.

**Geometrical tracery**, in architecture and decoration, tracery arranged in geometrical figures.

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