Phlegræan Fields. Campi Phlegræi, or "the Burnt Fields." The country around Naples, so named by the Greeks, from the traces of igneous action everywhere visible.
Phonolite. See "Clinkstone."
Phryganea. A genus of four-winged insects, the larvæ of which, called caddis-worms, are used by anglers as a bait.
Physics. The department of science which treats of the properties of natural bodies, laws of motion, &c.; sometimes called natural philosophy and mechanical philosophy. Etym., φυσις, physis, nature.
Phytology, Phytological. The department of science which relates to plants—synonymous with, botany and botanical. Etym., φυτον, phyton, plant, and λογος, logos, discourse.
Phytophagous. Plant-eating. Etym., φυτον, phyton, plant, and φαγειν, phagein, to eat.
Pisolite. A stone possessing a structure like an agglutination of peas. Etym., πισον, pison, pea, and λιθος, lithos, stone.
Pistia. P. 618. The plant mentioned by Malte-Brun is probably the Pistia Stratiotes, a floating plant, related to English duckweed, but very much larger.
Pit Coal. Ordinary coal; called so, because it is obtained by sinking pits in the ground.
Pitchstone. A rock of a uniform texture, belonging to the unstratified and volcanic classes, which has an unctuous appearance like indurated pitch.