Former le Peloton, Fr. to double up or form subdivision.
Pelotonne, ée, Fr. formed into a platoon.
Pelotonner, Fr. to gather together, to get into groupes.
Se Pelotonner, Fr. to form into a platoon.
PELTA, in antiquity, a kind of buckler, small, light, and more manageable than the Parma which was used by the Amazons, according to Virgil, and resembled the moon in his first quarter, according to Servius.
PENAL, (Pénal, ale, Fr.) any decree or law which subjects individuals, &c. to penalties. Hence code pénal. Les loix pénales. The penal code, the penal laws. Thus in England a person professing the Catholic religion is not permitted to exercise his religion if a soldier; and a catholic cannot be a commissioned officer.
PENALTY. In a military sense, signifies forfeiture for non-performance, likewise punishment for embezzlement, &c. An officer found guilty of embezzling stores is cashiered; any person who harbors, conceals, or assists any deserter from the United States’ service, is liable to a heavy penalty.
PENDULUM, in mechanics, any heavy body suspended in such a manner that it may vibrate backwards, and forwards, about some fixed point, by the force of gravity.
A pendulum is any body suspended upon, and moving about, a point as a centre. The nature of a pendulum consists in the following particulars. 1. The times of the vibrations of a pendulum, in very small arches, are all equal. 2. The velocity of the bob in the lowest point, will be nearly as the length of the cord of the arch which it describes in the descent. 3. The times of vibrations in different pendulums, are the square roots of the times of their vibrations. 4. The time of one vibration is to the time of descent, through half the length of the pendulum as the circumference of a circle is to its diameter. 5. Whence the length of a pendulum vibrating seconds in the latitude of London, is found to be 39 inches and ²⁄₁₀ths; and of one half-second pendulum 9.8 inches. 6. An uniform homogeneous body, as a rod, staff, &c. which is ¹⁄₃d part longer than a pendulum, will vibrate in the same time with it.
From these properties of the pendulum we may discern its use as an universal chronometer, or regulator of time. By this instrument, also, we can measure the distance of a ship, of a battery, &c. by measuring the interval of time between the fire and report of the gun; also the distance of a cloud, by counting the seconds or half-seconds, between the lightning and the thunder. Thus, suppose between the lightning and thunder we count ten seconds; then, because sound passes through 1142 feet in one second, we get the distance of the cloud = 11420 feet. Again, the height of any room, or other object, may be measured by a pendulum vibrating from the top thereof. Thus, suppose a pendulum from the height of a room, or other object, vibrates once in three seconds; then say, as 1 is to the square of 3, viz. 9, so is 39.2 to 352.8 feet, the height required. Lastly, by the pendulum we discover the different force of gravity on divers parts of the earth’s surface, and thence the true figure of the earth.