Page:EB1911 - Volume 18.djvu/281

 birth therefore is never the creation of a soul, but only a transmigration from one body to another. Plato’s acceptance of the doctrine is characteristic of his sympathy with popular beliefs and desire to incorporate them in a purified form into his system. Aristotle, a far less emotional and sympathetic mind, has a doctrine of immortality totally inconsistent with it. In later Greek literature the doctrine appears from time to time; it is mentioned in a fragment of Menander (the Inspired Woman) and satirized by Lucian (Gallus § 18 seq.). In Roman literature it is found as early as Ennius, who in his Calabrian home must have been familiar with the Greek teachings which had descended to his times from the cities of Magna Graecia. In a lost passage of his Annals, a Roman history in verse, Ennius told how he had seen Homer in a dream, who had assured him that the same soul which had animated both the poets had once belonged to a peacock. Persius in one of his satires (vi. 9) laughs at Ennius for this: it is referred to also by Lucretius (i. 124) and by Horace (Epist. II. i. 52). Virgil works the idea into his account of, the Underworld in the sixth book of the Aeneid (vv. 724 sqq.). It persists in antiquity down to the latest classic thinkers, Plotinus and the other Neoplatonists.

Attempts have been made with little success to find metempsychosis in early Jewish literature. But there are traces of it in Philo, and it is definitely adopted in the Kabbala. Within the Christian Church it was held during the first centuries by isolated Gnostic sects, and by the Manichaeans in the 4th and 5th centuries, but was invariably repudiated by orthodox theologians. In the middle ages these traditions were continued by the numerous sects known collectively as Cathari. At the Renaissance we find the doctrine in Giordano Bruno, and in the 17th century in the theosophist van Helmont. A modified form of it was adopted by Swedenborg. During the classical period of German literature metempsychosis attracted much attention: Goethe played with the idea, and it was taken up more seriously by Lessing, who borrowed it from Charles Bonnet, and by Herder. It has been mentioned with respect by Hume and by Schopenhauer. Modern theosophy, which draws its inspiration from India, has taken metempsychosis as a cardinal tenet; it is, says a recent theosophical writer, “the master-key to modern problems,” and among them to the problem of heredity.

Outside the somewhat narrow circle of theosophists there is little disposition to accept the doctrine: but it may be worth while, to point out that there are two fatal objections to it. The first is that personal identity depends on memory, and we do not remember our previous incarnations. The second is that the soul, whatever it may be, is influenced throughout all its qualities by the qualities of the body: modern psychology discredits the idea that the soul is a metaphysical essence which can pass indifferently from one body to another. If (to suppose the impossible) the soul of a dog were to pass into a man's body it would be so changed as to be no longer the same soul; and so, in a less degree, of change from one human body to another.

See A. Bertholet, The Transmigration of Souls (trans. from the German by H. J. Chaytor); E. Rohde, Psyche.

METEOR (Gr. , literally “things in the air,” from  , beyond, and  , to lift up), a term originally applied by the ancient Greeks to many atmospheric phenomena&mdash;rainbows, halos, shooting stars, &c.&mdash;but now specially restricted to those luminous bodies known as shooting stars, falling stars, fireballs and bolides. Though these objects only become visible in the atmosphere they are extra-terrestrial planetary bodies, and properly belong to the domain of astronomy. The extraterrestrial bodies which happen to find a resting-place on the earth are studied under the name of (q.v.).

In ancient times meteors were supposed to be generated in the air by inflammable gases. Isolated fireballs and star showers had been occasionally observed, but instead of being attentively watched they had been neglected, for their apparitions had filled mankind with dread, and superstition attributed to them certain malevolent influences. It was the brilliant exhibition in November 1833 that, in modern times particularly, attracted earnest students to investigate the subject of meteors generally, and to make systematic observations of their apparitions on ordinary nights of the year. Historical records were searched for references to past meteoric displays, and these were tabulated and compared. The attention devoted to the matter soon elucidated the phenomena of meteors, and proved them to be small planetary bodies, practically infinite in numbers and illimitable in the extent and variety of their orbits.

The various kinds of meteors are probably but different manifestations of similar objects. Perhaps the most important meteors are those which, after their bright careers and loud detonations, descend, upon the earth's surface and can be submitted to close inspection and analysis (see s). The fireball or bolide (Gr. , a missile) comes next in order from its size and conspicuous effects. It may either be interspersed with many smaller meteors in a shower or may be isolated. The latter usually move more slowly and approach rather near to the earth. The ordinary shooting stars vary from the brilliancy of a first- to a sixth-magnitude star. They exhibit a great dissimilarity in paths, motions and colours. The smallest and most numerous class are the telescopic meteors invisible to the naked eye. They range from the 7th magnitude to the smallest object perceptible in large telescopes.

The altitudes at which these bodies are visibly presented to us differ in individual cases. More than a thousand observations in duplicate have been made of the paths of identical meteors seen from two stations many miles apart. These pairs of observations have shown a parallax from which the elevation of the objects above the earth, the lengths and directions of their courses, &c. could be computed. The average heights are from 80 to 40 m. A few, however, first appear when higher than 80 m. and some, usually slow-moving meteors, descend below 40 m. But altitudes beyond 100 and within 20 m. are rare:— 30 of the November Leonids give a mean height of 84 to 57 m. 40 of the August Perseids   80&numsp; to 54 m.

When the length of a meteor’s course is known and the duration of its flight has been correctly estimated it is easy to compute the velocity in miles. The visible life of an ordinary shooting star is, however, comprised within one second, and it is only rarely that such short time intervals can be accurately taken. The real velocities derived from good observations are rarely, if ever, under 7 or 8 m. per second, or over 60 or 70 m. per second. In a few exceptional cases abnormal speed has been indicated on good evidence. The slower class of meteors overtaking the earth (like the Andromedids of November) have a velocity of about 8 or 10 m. per second, while the swifter class (meeting the earth like the Leonids of November) have a velocity of about 44 m. per second.

When the members of a shower are observed with special regard to their directions it is seen that they diverge from a common focus. The apparent scattering or diversity of the flights is merely an effect of perspective upon objects really traversing parallel lines. The centre upon which the observed paths converge is called the radiant point or, shortly, the radiant. On every night of the year there are a great number of these radiants in action, but the large majority represent very attenuated showers. In 1876 the number of radiants known was 850, but about 5000 have been determined up to the present time. These are not all the centres of separate systems, however: many of the positions being multiple observations of the same showers. Thus the August Perseids, the returns of which have been witnessed more frequently than those of any other meteoric stream have had their radiant point fixed on more than 250 occasions.

There appear to be moving and stationary radiants, contracted and diffused radiants, and long-enduring and brief radiants. The Perseids are visible from about the 11th of July to the 20th 