The eye to follow it, erewhile it rest;
And seems some star that shifted place in heaven.”
Dante.
No one can contemplate the firmament for long on a clear moonless night without noticing one or more of those luminous objects called shooting-stars. They are particularly numerous in the autumnal months, and will sometimes attract special attention either by their frequency of apparition or by their excessive brilliancy in individual cases. For many ages little was known of these bodies, though some of the ancient philosophers appear to have formed correct ideas as to their astronomical nature. Humboldt says that Diogenes of Apollonia, who probably belonged to the period intermediate between Anaxagoras and Democritus, expressed the opinion that, “together with the visible stars, there are invisible ones which are therefore without names. These sometimes fall upon the Earth and are extinguished, as took place with the star of stone which fell at Ægos Potamoi.” Plutarch, in the ‘Life of Lysander,’ remarks:—“Falling stars are not emanations or rejected portions thrown off from the ethereal fire, which when they come into our atmosphere are extinguished after being kindled: they are, rather, celestial bodies which, having once had an impetus of revolution, fall, or are cast down to the Earth, and are precipitated, not only on inhabited countries, but also, and in greater numbers, beyond these into the great sea, so that they remain concealed.”
In later times, however, opinions became less rational. Falling stars were considered to be of a purely terrestrial nature, and originated by exhalations in the upper regions of the air. Shakespeare expressed the popular belief when he wrote:—
“I shall fall
Like a bright exhalation in the evening,
And no man see me more.”
Another theory, attributed to Laplace, Arago, and others, was that meteors were ejections from lunar volcanoes. But these explanations were not altogether satisfactory in their application. The truth is, that men had commenced to theorize before they had begun to observe and accumulate facts. They had learnt little or nothing as to the numbers, directions, and appearances of meteors, and therefore possessed no materials on which to found any plausible hypothesis to account for them.
Meteoric Apparitions.—The occasional apparition of brilliant detonating fireballs, the occurrence of remarkable star-showers, the precipitation upon the Earth’s surface of stony masses, were facts which could be verified from many independent sources, and they set men thinking how to account for the strange and startling freaks of nature as exhibited in such phenomena. But though records existed of exceptionally large meteors and of meteor-showers, the descriptions were imperfect and failed in the most important details. The observers were usually unprepared for witnessing such events, and gave exaggerated and inaccurate accounts of what they had seen. The vivid brightness of a fireball (overpowering the lustre of the stars, and even vieing with the Moon in splendour), the flaming train left in its wake (curling itself up into grotesque shapes, as it drifted and died away), the form of the nucleus with its jets and sparks, and the final explosion, with the reverberations it caused, were all alluded to by the enthusiastic observer; but it was only in rare cases that the more valuable features were placed on record. The direction and duration of the meteor’s flight amongst the stars were facts of greater significance than the mere visible aspect of the object; but they were seldom regarded. Hence the early observations proved of little weight in inducing just conceptions as to the phenomena of meteors.