Pressure-gauge. Called also pressure-plug. An apparatus invented by Gen. Rodman for measuring the pressure exerted by the gases of exploded powder. It consists essentially of a steel plunger, on the head of which the pressure is exerted. The other end of the plunger is widened out into two cutting edges which meet at an obtuse angle. This point rests on a disk of copper, into which the cutter is driven by the pressure. The pressure is deduced from the length of the cut. Two forms of the instrument are used,—one is placed in a hole bored through the side of the gun. The other is complete in itself and is placed at the bottom of the cartridge-bag. Lieut. Metcalfe’s (U. S. Ordnance Corps) modification of the pressure-gauge has a cutter with a helicoidal edge. To measure the cut he uses a circular scale with a hole in the centre (in which the inducted copper is placed), and a radial arm to show the extent of the spiral cut. The English modification of Rodman’s instrument is called the crusher-gauge,—a short cylinder of copper is substituted for the disk,—the reduction in its length gives a measure of the pressure. The crusher-gauge is frequently attached to the base of the shot. A similar modification is used to test the power of the high explosives, such as dynamite, dualin, etc. A lead cylinder is crushed in this case. A very small charge is used. The reaction is obtained by placing a heavy cylindrical shot over the charge, which rests directly in a cavity on the top of the plunger.
Preston. A town of England, in Lancashire, on the north bank of the Ribble. This town was partially destroyed by Bruce in 1322; and after declaring for the king, it was taken by the forces of the Parliament under Gen. Fairfax. Here also ended the ill-fated Jacobite rising of 1715, when, after a brave resistance, the insurgents were compelled to surrender.
Prestonpans. A village of Haddingtonshire, 8 miles east of Edinburgh. In the vicinity, on September 21, 1745, was fought the famous battle of Prestonpans, between the royal troops under Sir John Cope and the Jacobites under Prince Charles, in which the latter, with a loss of only about 10 officers and 120 men in killed and wounded, routed the royal forces with great slaughter, and captured their cannon, baggage, and military chest.
Pretence, Escutcheon of, or Escutcheon Surtout. In heraldry, a small shield placed in the centre of the field of another shield. The husband of an heiress may bear the arms of his wife in an escutcheon of pretence, instead of impaling them. Feudal arms are also sometimes placed on an escutcheon of pretence, particularly in the insignia of elective sovereigns, who have been in use of bearing their own proper arms in surtout over those of the dominions to which they are entitled.
Pretorian. Appertaining to pretor; also the general’s guard among the ancient Romans.
Pretorium. The hall or court where the pretor lived and administered justice. It also denoted the tent of the Roman general, in which councils of war were held. The place where the pretorian guards were quartered or lodged, was likewise called pretorium.
Prevesa. A fortified town of European Turkey, in Albania, on the north shore of the Gulf of Arta, 58 miles south-southwest of Yanina. Prevesa belonged to the Venetians from 1684 until the fall of that republic in 1797. It was then held by the French for a time, but was afterwards taken by the Turks.
Prey. Anything, as goods, etc., taken by force from an enemy in war; spoil; booty; plunder.
Pricker. A light horseman was formerly so called.
Pricker. A [priming-wire] (which see).