Opisthodomos, Gr. (ὀπισθό-δομος). Latin, Posticum. A small chamber placed at the back of a temple, to which the priests alone had access.
Oporotheca, Gr. (ὀπωρο-θήκη). A storehouse for fruits.
Oppidan. At Eton College, a boy who is not a king’s scholar, and boards in the town.
Fig. 502. Oppidum and carceres of the circus of Caracalla.
Oppidum, R. A fortified town, and thence the mass of buildings occupying the extremity of a circus, in which were the stalls for the chariots and horses (carceres). Fig. [502] gives a representation of the oppidum in the circus of Caracalla.
Optical Correction is a name given to the task of adapting art objects, or architectural proportions and ornaments, to the circumstances of distance or comparison in which they are to be exhibited. Belzoni observes that the heads of colossal Egyptian statues are proportionally larger than the lower members. (For numerous examples of this contrivance, see the article in the Architectural Publication Society’s Dictionary.)
Optics (Gr. ὄπτομαι, to see). The science of the nature and properties of light; of its changes as it penetrates or is reflected or absorbed by bodies; of the structure of the eye, and the laws of vision; and of instruments in connexion with sight. It is thus closely connected with the science of colour, and the arts in general. The earliest treatise extant on this science is Euclid’s Optica et Catoptrica. (Cf. Dr. Smith’s Optics, &c.)
Optigraph. A telescope for copying landscapes. (See Claude Glass.)
Optostratum, R. (ὀπτὸς, brick, and στρωτὸν, strewn). A brick pavement, often arranged in a herring-boned pattern, as in the Opus Spicatum. (Fig. [509].)