PICKET n.
game at cards. See Piquet. Inlying picket (Mil.), a detachment of troops held in camp or quarters, detailed to march if called upon. -- Picket fence, a fence made of pickets. See def. 2, above. -- Picket guard (Mil.), a guard of horse and foot, always in readiness in case of alarm. -- Picket line. (Mil.) (a) A posi…
PORPHYRITIC a.
g, porphyry, that is, characterized by the presence of distinct crystals, as of feldspar, quartz, or augite, in a relatively fine-grained base, often aphanitic or cryptocrystalline.
PORPHYRY n.
ng of a fine-grained base (usually feldspathic) through which crystals, as of feldspar or quartz, are disseminated. There are red, purple, and green varieties, which are highly esteemed as marbles. Porphyry shell (Zoöl.), a handsome marine gastropod shell (Oliva porphyria), having a dark red or brown polished surface,…
POSITIVE a.
for the ordinary ray, and the former is refracted nearer to the axis than the latter, as quartz and ice; -- opposed to negative crystal, or one in which this characteristic is reversed, as Iceland spar, tourmaline, etc. -- Positive degree (Gram.), that state of an adjective or adverb which denotes simple quality, wit…