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An inflammation; more particularly, an inflammation of the internal organs. Phlegmasia dolens ( Etym: [NL.], milk leg.

A double-lens instrument for measuring slight variations of the sun's diameter by photography, utilizing the common chord of two overlapping images.

Of certain achromatic lenses, having the same focus for the actinic and for the brightest of the visual rays.

A West African pie (Ptilostomus Senegalensis).

Plane or flat on one side, and concave on the other; as, a plano-concave lens. See Lens.

Plane or flat on one side, and convex on the other; as, a plano-convex lens. See Convex, and Lens.

Pole mast (Naut.), a mast formed from a single piece or from a single tree. -- Pole of a lens (Opt.), the point where the principal axis meets the surface. -- Pole plate (Arch.), a horizontal timber resting on the tiebeams of a roof and receiving the ends of the rafters. It differs from the plate in not resting on th…

Consisting of many zones or rings. Polyzonal lens (Opt.), a lens made up of pieces arranged zones or rings, -- used in the lanterns of lighthouses.

The degree to which a lens, mirror, or any optical instrument, magnifies; in the telescope, and usually in the microscope, the number of times it multiplies, or augments, the apparent diameter of an object; sometimes, in microscopes, the number of times it multiplies the apparent surface.

defect of vision consequent upon advancing age. It is due to rigidity of the crystalline lens, which producepresbytia.

e far point of distinct vision, -- usually measured and designated by the strength of the lens which if added to the refracting media of the eye would cause the rays from the near point to appear as if they came from the far point. -- Range finder (Gunnery), an instrument, or apparatus, variously constructed, for asce…

ding; esp., a desk used while reading the service in a church. -- Reading glass, a large lens with more or less magnifying power, attached to a handle, and used in reading, etc. -- Reading man, one who reads much; hence, in the English universities, a close, industrious student. -- Reading room, a room appropriated…

h the image to be viewed is formed by the refraction of light in passing through a convex lens.

erted position; as, the reversal of a rotating wheel; the reversal of objects by a convex lens.

A perennial suffrutescent plant (Ruta graveolens), having a strong, heavy odor and a bitter taste; herb of grace. It is used in medicine. Then purged with euphrasy and rue The visual nerve, for he had much to see. Milton. They [the exorcists] are to try the devil by holy water, incense, sulphur, rue, which from thence,…

A tool on which lenses are fastened in a group, for polishing or grinding.

bling, but distinct from, quercitrin. Rutin is found in the leaves of the rue (Ruta graveolens) and other plants, and obtained as a bitter yellow crystalline substance which yields quercitin on decomposition.

orming images in a darkened room, usually called scioptic ball. Scioptic ball (Opt.), the lens of a camera obscura mounted in a wooden ball which fits a socket in a window shutter so as to be readily turned, like the eye, to different parts of the landscape.

nous images, especially those of external objects, in a darkened room, by arrangements of lenses or mirrors.

ubsided. -- Secondary axis (Opt.), any line which passes through the optical center of a lens but not through the centers of curvature, or, in the case of a mirror, which passes through the center of curvature but not through the center of the mirror. -- Secondary battery. (Elec.) See under Battery, n., 4. -- Second…