Search the Dictionary

form the planes of which are parallel to the vertical axis. See Form, n., 13. Achromatic prism (Opt.), a prism composed usually of two prisms of different transparent substances which have unequal dispersive powers, as two different kinds of glass, especially flint glass and crown glass, the difference of dispersive p…

Glass with one side smooth and the other side formed into sharp-edged ridges so as to reflect the light that passes through, used at windows to throw the light into the interior.

Resembling, or pertaining to, a prism; as, a prismatic form or cleavage.

In the form on manner of a prism; by means of a prism.

Having a prismlike form. Ure.

A body that approaches to the form of a prism.

Having the form of a prismoid; as, prismoidal solids.

Pertaining to a prism. [R.]

A prism whose refracting angle is very nearly 180 degrees.

Doubly prismatic.

A prism of an orthorhombic crystal between the macropinacoid and the unit prism; the corresponding pyramids are called macropyramids.

corrected by other, and light emerges from the compound lens undecomposed. -- Achromatic prism. See Prism. -- Achromatic telescope, or microscope, one in which the chromatic aberration is corrected, usually by means of a compound or achromatic object glass, and which gives images free from extraneous color.…

A silicate of aluminium, occurring usually in thick rhombic prisms, nearly square, of a grayish or pale reddish tint. It was first discovered in Andalusia, Spain.

A native sulphate of lead. It occurs in white or yellowish transparent, prismatic crystals.

Native phosphate of lime, occurring usually in six-sided prisms, color often pale green, transparent or translucent.

A mineral relating to the zeolites, usually occurring in square prisms or octahedrons with pearly luster on the cleavage surface. It is a hydrous silicate of calcium and potassium.

An oxychloride of copper, usually in emerald-green prismatic crystals.

ar to the plane of vibration. -- Axis of polarization, the central line around which the prismatic rings or curves are arranged. Brewster. -- Axis of revolution (Descriptive Geom.), a straight line about which some line or plane is revolved, so that the several points of the line or plane shall describe circles with…

mineral of great hardness, and, when transparent, of much beauty. It occurs in hexagonal prisms, commonly of a green or bluish green color, but also yellow, pink, and white. It is a silicate of aluminium and glucinum (beryllium). The aquamarine is a transparent, sea-green variety used as a gem. The emerald is another…

ing of two pyramids placed base to base; having a pyramid at each of the extremities of a prism, as in quartz crystals.