Encyclopaedia Americana: a popular dictionary of arts, sciences, literature, history, politics and biography, brought down to the present time : including a copious collection of original articles in American biography : on the basis of the seventh edition of the German Conversations-Lexicon (Volume 10).
- Date:
- 1830-33
Licence: Public Domain Mark
Credit: Encyclopaedia Americana: a popular dictionary of arts, sciences, literature, history, politics and biography, brought down to the present time : including a copious collection of original articles in American biography : on the basis of the seventh edition of the German Conversations-Lexicon (Volume 10). Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![PENANCE—PENDULUM. flicts penance, as a satisfaction to his own conscience and to God. Confession was not invented by Innocent III, but only enjoined by him at least once a year. It is followed by absolution, according to the authority transmitted to the church, and by the im])osition of such penances as are necessary to free from the conse- quences of sin. The council of Trent declares, in sess. xiv, c. 8, that satisfaction for sin is effected only by Christ, and it is left for the individual to bring forth fruits worthy of repentance. Days of penance and fasting are holy days, which, in certain countries, are fixed annually, or after gen- eral calamities, for the purpose of a gene- ral expression of penitence, or with the view of appeasing the anger of the Deity. Tin; great day of fasting among the Jews is the Long Night. The Christians imi- tated these fast-days, Penates ; the private or public gods of the Romans; in the former sense, they resembled the Lares (q. v.), with whom they are often confounded. Not only every house, but every city, had its Penates, and the latter were the public gods. The most celebrated at Rome were those that protected the empire. These were brought into Italy by iEiieas, together with Vesta and her eternal fire. According to Varro and Macrobius, the Penates were rude im- agesofwoodorstone,furnishedwithaspear; and generals, on their departure, and con- suls, pretorsand dictators, whentheyretired from office, sacrificed victims before them. Pencil; an instrument used by paint- ers for laying on their colore. Pencils are of various kinds, and made of various materials; the larger sorts are made of boar's bristles, the thick ends of which ire bound to a stick, large or small, according to the uses they are designed for; these, when large, are called brushes. The finer sorts of pencils are made of camels', badgers' and squirrels' hair, and of the down of swans; these are tied at the up- per end with a piece of strong thread, and enclosed in the barrel of a quill. Good pencils, when drawn between the lips, come to a fine point. Lead Pencils. (See Plumbago.) Pencil of Rays; a number of rays di- verging from some luminous point, which, lifter passing through a lens, converge again to a point. Pendant. Two paintings or prints of equal dimensions, which are attached in corresponding positions to the same wall, are called pendants to each other. Pendant, or Pennant ; a sort of long narrow banner displayed from the mast- head of a ship-of-war, and usually ter- minating in two ends or points, called the swallow's-tail. It denotes that a vessel is in actual service.—Broad petulant is a kind of flag terminating in one or two points, used to distinguish the chief of a squadron.—Pendant is also a short piece of rope, fixed on each side, under the shrouds, upon the heads of die main and fore masts. Pendulum, in dynamics, is a simple ponderous body, so suspended by a flexi- ble cord from an axis of suspension, that it is at liberty to vibrate by the action of its own gravity alone, when it is once raised, by any external force, to the right or left of its quiescent position; and, in demonstrating the theory of its motion, mathematicians are obliged to assume, that there is no rigidity in the cord, no friction at the axis of suspension, no re- sistance to motion made by the air, and no variation in the total length of the cord, arising from the variable temperature or moisture of the atmosphere; and if these assumptions were strictly correct, a pen- dulum, once put in motion, would con- tinue to move, ad infinitum, without a further accession of any external force; but, when the pendulum is applied as the regulator of a clock, for which purpose it is admirably* adapted, the assumptions which we have stated, require an equal number of mechanical corrections, of which the theory, simply considered, takes no notice, in horology, therefore, the pendulum must be considered not simply as a self-moving pendulous body, without any tendency to come to a state of rest, but as a body whose motion is perpetuated by repeated accessions of force in aid of its own gravity, and whose vibrations are rendered isochronal by a nice adaptation of mechanical conniv- ances, that prevent or remedy the influ- ence of all natural impediments to uni- form and uninterrupted motion. The first kind of pendulum (the theoretical) is called a mathematical or simple pendulum, the other the physical or compound pendulum. In the mathematical pendulum, the matter of the pendulous ball or bob is supposed to be collected into one point, so that the centres of gravity and of oscillation coin- cide. The doctrine of the pendulum is of the highest importance, but, as it can- not be fully developed without the aid of mathematics, nor rendered clear without diagrams, we can state only some of the most obvious properties and circum- stances connected with it. A pendulum, once put in motion, would never cease to](https://iiif.wellcomecollection.org/image/b21136798_0008.jp2/full/800%2C/0/default.jpg)
