persoonidæ

pl. [Mod. Lat. per so on ( ia ); Lat. fem. pl. adj. suff. -idœ.] Bot .: A family or tribe of Proteaceae, section Nucamentaceæ. per-spěc-tive, a . & s. [Fr. perspectif , fem. perspective, from Lat. perspectiva ( ars )=(the art of) thoroughly inspecting, from perspectus , pa. par. of perspicio to see through or clearly: per through, and specio =to see; Sp. perspectivo .] A. As adjective : 1. Pertaining to the science of vision; optic, optical. 2. Producing certain optical effects when looked through; optic. "A perspective gla e whereby was shewed many strange sights, ."-Hackluyt: Voyages , iii. 277. 3. Pertaining to the art of perspective. B. As substantive: I. Ordinary Language : perspicuity dealt with by Aerial Perspective. A practical knowledge of the science is absolutely a nece ity for a succe ful artist. 2. A kind of painting designed expre ly to deceive the sight by representing the continuation of an alley, a building, a landscape, or the like. (1) Isometric perspective : [ISOMETRIC.) 2 (2) Obiique (or angular ) perspective : Where the plane of the picture is supposed to be at an angle to the side of the principal object in the picture, as. for instance, a building. (3) Parallel perspective : Where the plane of the picture is parallel to the side of the principal object in the picture. (4) Perspective plane: The surface upon which the objects are delineated, or the picture drawn. It is supposed to be placed vertically between the eye of the spectator and the object. Also termed the plane of projection, or the plane of the picture.