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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 from the light, negative phototaxis. --Pho`to*tac"tic (#), a. --Pho`to…

Very soft; -- a direction to execute a passage as softly as possible. (Abbrev. pp.)

Soft; -- a direction to the performer to execute a certain passage softly, and with diminished volume of tone. (Abbrev. p.)

e. [U.S.] Pilot balloon, a small balloon sent up in advance of a large one, to show the direction and force of the wind. -- Pilot bird. (Zoöl.) (a) A bird found near the Caribbee Islands; - - so called because its presence indicates to mariners their approach to these islands. Crabb. (b) The black-bellied plover. [Loc…

A small, unmanned balloon sent up to indicate the direction of air currents.

is. -- Pivot gun, a gun mounted on a pivot or revolving carriage, so as to turn in any direction. -- Pivot tooth (Dentistry), an artificial crown attached to the root of a natural tooth by a pin or peg.

A direction to violinists to pluck the string with the finger, instead of using the bow. (Abrev. pizz.)

The property possessed by some crystals, of showing different colors when viewed in the direction of different axes.

ad, or the like, attached to a line, and used by builders, etc., to indicate a vertical direction; a plummet; a plumb bob. See Plumb line, below. Plumb bob. See Bob, 4. -- Plumb joint, in sheet-metal work, a lap joint, fastened by solder. -- Plumb level. See under Level. -- Plumb line. (a) The cord by which a plumb…

Bent; turn; direction; bias. The late learners can not so well take the ply. Bacon. Boswell, and others of Goldsmith's contemporaries, . . . did not understand the secret plies of his character. W. Irving. The czar's mind had taken a strange ply, which it retained to the last. Macaulay.

stars (Merak and Dubhe) in the Great Bear, the line between which points nearly in the direction of the north star. See Illust. of Ursa Major. (b) pl. (Naut.)

The act of designating, as a position or direction, by means of something pointed, as a finger or a rod.

its opposite, or contrasted, properties or powers, in opposite, or contrasted, parts or directions; or a condition giving rise to a contrast of properties corresponding to a contrast of positions, as, for example, attraction and repulsion in the opposite parts of a magnet, the dissimilar phenomena corresponding to the…

f light or heat, in consequence of which they exhibit different properties in different directions.

Tending to a pole; having a direction toward a pole. [R.] Sir T. Browne.

One of the opposite or contrasted parts or directions in which a polar force is manifested; a point of maximum intensity of a force which has two such points, or which has polarity; as, the poles of a magnet; the north pole of a needle.

), a polygonal figure, the sides of which, taken successively, represent, in length and direction, several forces acting simultaneously upon one point, so that the side necessary to complete the figure represents the resultant of those forces. Cf. Parallelogram of forces, under Parallelogram.

and by comparing the difference of the results with those of the numbers, deducing the correction to be applied to one of them to obtain the true result. -- Guns of position (Mil.), heavy fieldpieces, not designed for quick movements. -- Position finder (Mil.), a range finder. See under Range. -- Position micrometer…

ts on a vertical axis firmly fastened to the ground, and capable of being turned as the direction of the wind varies. -- Post and stall (Coal Mining), a mode of working in which pillars of coal are left to support the roof of the mine.

f postage than a sealed letter. The message is written on one side of the card, and the direction on the other. -- Postal money order. See Money order, under Money. -- Postal note, an order payable to bearer, for a sum of money (in the United States less than five dollars under existing law), issued from one post off…