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The science or art of delineating objects according to the laws of perspective; the theory of perspective.

pertaining to perturbation, esp. to the perturbations of the planets. "The perturbational theory." Sir J. Herschel.

Petted; indulged; admired; cherished; as, a pet child; a pet lamb; a pet theory. Some young lady's pet curate. F. Harrison. Pet cock. Etym: [Perh. for petty cock.] (Mach.) A little faucet in a water pipe or pump, to let air out, or at the end of a steam cylinder, to drain it.

That theory which limits positive or scientific knowledge to phenomena only, whether material or spiritual.

One who believes in the theory of phenomenalism.

A particular philosophical system or theory; the hypothesis by which particular phenomena are explained. [Books] of Aristotle and his philosophie. Chaucer. We shall in vain interpret their words by the notions of our philosophy and the doctrines in our school. Locke.

d as in animal physiology. The details of the process are not yet clearly known. Baeyer's theory is that the carbon dioxide is reduced to carbon monoxide, which, uniting with the hydrogen of the water in the cell, produces formaldehyde, the latter forming various sugars through polymerization. Vines suggests that the c…

The art of healing diseases; the science of medicine; the theory or practice of medicine. "A doctor of physik." Chaucer.

A believer in the theory that the fundamental phenomena of life are to be explained upon purely chemical and physical principles; -- opposed to vitalist.

The theory that the various genera of bacteria are phases or variations of growth of a number of Protean species, each of which may exhibit, according to undetermined conditions, all or some of the forms characteristic of the different genera and species.

f, pertaining to, or designating, the system of the Plutonists; igneous; as, the Plutonic theory. Plutonic action (Geol.), the influence of volcanic heat and other subterranean forces under pressure. -- Plutonic rocks (Geol.), granite, porphyry, and some other igneous rocks, supposed to have consolidated from a melted…

The theory, early advanced in geology, that the successive rocks of the earth''s crust were formed by igneous fusion; -- opposed to the Neptunian theory.

One who adopts the geological theory of igneous fusion; a Plutonian. See Plutonism.

The theory that living organisms originate in cells or embryos of different kinds, instead of coming from a single cell; -- opposed to monogenesis.

In the broadest sense, the theory or practice of any of several groups of recent painters, or of these groups taken collectively, whose work and theories have in common a tendency to reaction against the scientific and naturalistic character of impressionism and neo- impressionism. In a strict sense the term post-impre…

In the theory of gravitation, or of other forces acting in space, a function of the rectangular coordinates which determine the position of a point, such that its differential coefficients with respect to the coördinates are equal to the components of the force at the point considered; -- also called potential function…

Actual performance; application of knowledge; -- opposed to theory. There are two functions of the soul, -- contemplation and practice. South. There is a distinction, but no opposition, between theory and practice; each, to a certain extent, supposes the other; theory is dependent on practice; practice must have preced…

ice; especially, exercise or discipline for a specific purpose or object. "The praxis and theory of music." Wood.

The theory of a preëxistence of souls before their association with human bodies. Emerson.

An old theory of the preëxistence of germs. Cf. Emboîtement.