PHONOGRAPH n.
n, etc., above which is a thin plate carrying a stylus. As the plate vibrates under the influence of a sound, the stylus makes minute indentations or undulations in the soft material, and these, when the cylinder or disk is again turned, set the plate in vibration, and reproduce the sound.
PHOTOTAXIS; PHOTOTAXY n.
The influence of light on the movements of low organisms, as various infusorians, the zoöspores of certain algæ, etc.; also, the tendency to follow definite directions of motion or assume definite positions under such influence. If the migration is toward the source of light, it is termed positive phototaxis; if away f…
PLIABLE a.
Flexible in disposition; readily yielding to influence, arguments, persuasion, or discipline; easy to be persuaded; -- sometimes in a bad sense; as, a pliable youth. "Pliable she promised to be." Dr. H. More. -- Pli"a*ble*ness, n. -- Pli"a*bly, adv.
PLUTONIC a.
ystem 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 state at a great depth from the surfac…