PENDULUMS. Pendulums for military purposes are best made with a musquet ball, and a piece of silk, or other small line. Their length must be measured from the centre of the ball to the end of the loop on which they are to swing. In a cylinder, or other uniform prism or rod, the centre of oscillation, from whence they must be measured, is at the distance of one-third from the bottom, or two-thirds below the centre of motion.

Pendulum’s length in latitude of London, to swing

Seconds39¹⁄₈th.
¹⁄₂Seconds9·8
¹⁄₄Seconds2·45

Length of Pendulums to vibrate Seconds at every fifth degree of latitude.

Degrees
of
Latitude.		Length
of
Pendulum.
Inches.
39,027
 539,029
1039,032
1539,036
2039,044
2539,057
3039,070
3539,084
4039,097
4539,111
5039,126
5539,142
6039,158
6539,168
7039,177
7539,185
8039,191
8539,195
9039,197

Rule.—To find the length of a pendulum to make any number of vibrations, and vice versa.

Call the pendulum making 60 vibrations the standard length; then say, as the square of the given number of vibrations is to the square of 60; so is the length of the standard to the length sought. If the length of the pendulum be given and the number of vibrations it makes in a minute be required; say, as the given length, is to the standard length, so is the square of 60, its vibrations in a minute, to the square of the number required. The square root of which will be the number of vibrations made in a minute.

PENNANT, PENNON, a small flag or color.

Gentlemen PENSIONERS, (Gentilshommes Pensionnaires, Fr.) a band of gentlemen, who guard the British king’s person in his own house, and for that end wait in the presence chamber. They were first instituted by Henry VII. They are usually forty in number. Their officers are, a captain, lieutenant, standard-bearer, and clerk of the cheque. Their ordinary arms are guilt pole-axes. Their pension is 100l. per annum; they are usually called beef-eaters, from their usually fat appearance and indolent habits.

PENTACAPSULAR, having five cavities.