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The act of defining; determination of the limits; as, the telescope accurate in definition.

A sort of electroscope, invented by Rousseau, in which the dry pile is employed to measure the amount of electricity transmitted by different bodies, or to determine their conducting power. Nichol.

Having the quality of unloosing or separating. Clarke. Dialytic telescope, an achromatic telescope in which the colored dispersion produced by a single object lens of crown glass is corrected by a smaller concave lens, or combination of lenses, of high dispersive power, placed at a distance in the narrower part of the…

in instruments to cut off marginal portions of a beam of light, as at the focus of a telescope.

Pertaining to the dichroscope, or to observations with it.

Extent; reach; scope; importance; as, a project of large dimensions.

of the refraction of light; refractive; as, the dioptric system; a dioptric glass or telescope. "Dioptrical principles." Nichol. Dioptric curve (Geom.), a Cartesian oval. See under Cartesian.

out, or perceived; as, many minute animals are discoverable only by the help of the microscope; truths discoverable by human industry.

appearing as a point and not expanded into a disk, as the image of a faint star in a telescope.

Used for or in dissecting; as, a dissecting knife; a dissecting microscope.

(Astron.), two stars so near to each other as to be seen separate only by means of a telescope. Such stars may be only optically near to each other, or may be physically connected so that they revolve round their common center of gravity, and in the latter case are called also binary stars. -- Double time (Mil.). Sam…

a very small quantity of electricity, so as to render it manifest by sparks or the electroscope.

An arrangement of two lenses for a microscope, designed to correct spherical aberration and chromatic dispersion, thus rendering the image of an object more clear and distinct. W. H. Wollaston.

of a liquid, affording a feeble current, and chiefly useful in the construction of electroscopes of great delicacy; -- called also Zamboni's , from the names of the two earliest constructors of it. -- Dry pipe (Steam Engine), a pipe which conducts dry steam from a boiler. -- Dry plate (Photog.), a glass plate having…

A level having a short telescope (hence its name) rigidly fixed to a table capable only of rotatory movement in a horizontal plane. The telescope is usually an inverting one. It is sometimes called the Troughton level, from the name of the inventor, and a variety improved by one Gavatt is known as the Gavatt level.…

An instrument for determining the magnifying power of telescopes, consisting usually of a doubleimage micrometer applied to the eye end of a telescope for measuring accurately the diameter of the image of the object glass there formed; which measurement, compared with the actual diameter of the glass, gives the magnify…

Room to extend the elbows on each side; ample room for motion or action; free scope. "My soul hath elbowroom." Shak. Then came a stretch of grass and a little more elbowroom. W. G. Norris.

ed to an instrument which indicates the presence of electricity (usually called an electroscope). Balance electrometer. See under Balance.

Relating to, or made by means of, the electroscope.

The art or process of examining by means of the endoscope.