Shooting stars also, although they are not accompanied by the fall of any solid matter upon the earth, are generally placed in the same category, since they are supposed to be aërolites which pass (comparatively speaking) very near our earth, and are visible from it by night; at the same time their distance from us, varying as it does from four to two hundred and forty miles and upward, is in most instances too great to allow of their being drawn down by the attractive power possessed by the earth. Like comets and eclipses, these celestial phenomena in former times were universally regarded with feelings of the greatest awe and superstition; and in Eastern countries especially, where the fall of a meteoric stone was supposed to be the immediate precursor of some important public event, or national calamity, the precise date of each descent was carefully recorded. In China, for example, such reports reach back to the year 644 before our era; and M. Biot has found in the astronomical section of some of the most ancient annals of that empire sixteen falls of aërolites recorded as having taken place between the years 644 B.C. and 333 after Christ, whilst the Greek and Roman authors mention only four such occurrences during the same period. Even now, in this age of science and universal knowledge, aërolites can scarcely be regarded without a certain degree of dread. Indeed, four or five cases have occurred in which persons have been killed by them; in another instance, several villages in India were set on fire by the fall of a meteoric stone; and it was by no means a pleasant subject for reflection that such a catastrophe might happen anywhere and at any moment, especially when we remember that these stones, although not quite incandescent, are always, more or less, in a heated state; and sometimes so hot that even after the lapse of six hours they could not be touched with impunity.
The first fall of meteoric stones on record appears to have taken place about the year 654: B.C., when, according to a passage in Livy, a shower of stones fell on the Alban Hill, not far distant from Rome. The next in chronological order is mentioned by several writers, such as Diogenes of Apollonia, Plutarch, and Pliny, and described by them as a great stone, the size of two millstones, and equal in weight to a full wagon-load. It fell about the year 467 B.C., at AEgos Potamos, on the Hellespont, and even up to the days of Pliny, four centuries after its fall, it continued to be an object of curiosity and speculation. [{537}] After the close of the first century we fail to obtain any account or notice of this stone; but although it has been lost sight of for upward of eighteen hundred years, the eminent Humboldt says, in one of his works, that notwithstanding all previous failures to rediscover it, he does not wholly relinquish the hope that even after such a considerable lapse of time, this Thracian meteoric mass, which it would be so difficult to destroy, may be found again, especially since the region in which it fell has now become so easy to access to European travellers.
The next descent of any particular importance took place at Ensisheim in Alsace, where an aërolite fell on November 7th, 1492, just at the time when the Emperor Maximilian, then king of the Romans, happened to be on the point of engaging with the French army. It was preserved as a relic in the cathedral at Ensisheim, until the beginning of the French revolution, when it was conveyed to the Public Library of Colmar, and it is still preserved there among the treasures.
In later years the shower of aërolites which fell in April, 1803, at L'Aigle, in Normandy, may well rank as the most extraordinary descent upon record. A large fire-ball had been observed a few moments previously, in the neighborhood of Caen and Alençon, where the sky was perfectly clear and cloudless. At L'Aigle no appearance of light was visible, and the fire-ball assumed instead the form of a small black cloud, consisting of vapor, which suddenly broke up with a violent explosion, followed several times by a peculiar rattling noise. The stones at the time of their descent were hot, but not red, and smoked visibly. The number which were afterward collected within an elliptical area measuring from six to seven miles in length by three in breadth, has been variously estimated at from two to three thousand. They ranged in weight from two drachms up to seventeen and half pounds. The French government immediately deputed M. Biot, the celebrated naturalist and philosopher, to proceed to the spot, for the express purpose of collecting the authentic facts concerning a phenomenon which, until that time, had almost universally been treated as an instance of popular superstition and credulity. His conclusive report was the means of putting an end to all scepticism on the subject, and since that date the reality—not merely the possibility—of such occurrences has no longer been contested.
Leaving out, for the present, innumerable foreign instances which might be quoted, we must now glance rapidly at a few of the most noticeable examples of the fall of meteoric stones which have taken place in England. The earliest which appears on record descended in Devonshire, near Sir George Chudleigh's house at Stretchleigh, in the parish of Ermington, about twelve miles from Plymouth. The circumstance is thus related by Westcote, one of the quaint old Devonshire historians:
"In some part of this manor (Stretchleigh), there fell from above—I cannot say from heaven—a stone of twenty-three pounds weight, with a great and fearful noise in falling; first it was heard like unto thunder, or rather to be thought the report of some great ordnance, cannon, or culverin; and as it descended, so did the noise lessen, at last when it came to the earth to the height of the report of a peternel, or pistol. It was for matter like unto a stone singed, or half-burned for lime, but being larger described by a richer wit, I will forbear to enlarge on it."
The "richer wit" here alluded to was in all probability the author of a pamphlet published at the time, which further describes this aërolite as having fallen on January 10th, 1623, in an orchard, near some men who were planting trees. It was buried in the ground three feet deep, and its dimensions were three and a half feet long, two and a half wide, and one and a half thick. The pamphlet also states that pieces broken from off it were in the possession of many of the neighboring gentry. [{538}] We may here remark that no specimen of this stone is at present known to be in existence, and that although living in the county where it fell, we have hitherto failed in tracing any of the fragments here referred to. A few years later, in August, 1628, several meteoric stones, weighing from one to twenty-four pounds, fell at Hatford, in Berkshire; and in the month of May, 1680, several are said to have fallen in the neighborhood of London.
The total number of aërolitic descents which up to this present time have been observed to take place in Great Britain and Ireland is twenty, of which four occurred in Scotland, and four in Ireland. The largest and most noticeable of all these fell on December 13th, 1795, near Wold Cottage, in the parish of Thwing, East Riding of Yorkshire. Its descent was witnessed by two persons; and when the stone was dug up, it was found to have penetrated through no less than eighteen inches of soil and hard chalk. It originally weighed about fifty-six pounds, but that portion of it preserved in the British Museum is stated in the official catalogue to weigh forty-seven pounds nine ounces and fifty-three grains—just double the weight of the Devonshire aërolite.
When we come to inquire into the various opinions which have been held in different ages respecting the origin of aërolites, and the power which causes their descent, we must go back to the times of the ancient Greeks, and we find that those of their philosophers who had directed their attention to the subject had four theories to account for this singular phenomenon. Some thought that meteoric stones had a telluric origin, and resulted from exhalations ascending from the earth becoming condensed to such a degree as to render them solid. This theory was in after years revived by Kepler the astronomer, who excluded fire-balls and shooting stars from the domain of astronomy; because, according to his views, they were simply "meteors arising from the exhalations of the earth, and blending with the higher ether." Others, like Aristotle, considered that they were masses of metal raised either by hurricanes, or projected by some volcano beyond the limits of the earth's attraction, so becoming inflamed and converted, for a time, into starlike bodies. Thirdly, a solar origin; this, however, was freely derided by Pliny and several others, among whom we may mention Diogenes of Apollonia, already alluded to as one of the chroniclers of the aërolite of AEgos Potamos. He thus argues: "Stars that are invisible, and consequently have no name, move in space together with those that are visible. . . . These invisible stars frequently fall to the earth and are extinguished, as the stony star which fell burning at AEgos Potamos." This last opinion, it will be seen, coincides, as far as it goes, almost exactly with the most modern views on the subject.
As some of the Greeks derived the origin of meteorites from the sun (probably from the fact of their sometimes falling during bright sunshine), so we find, at the end of the seventeenth century, it was believed by a great many that they fell from the moon. This conjecture appears to have been first hazarded by an Italian philosopher, meeting Paolo Maria Terzago, whose attention was specially directed to this subject on the occasion of a meteoric stone falling at Milan in 1660, and killing a Franciscan monk. Olbers, however, was the first to treat this theory in a scientific manner, and soon after about fall of an aërolite at Siena, in the year 1794, he began to examine the question by the aid of the most abstruse mathematics, and after several years' labor he succeeded in showing that, in order to reach our earth, a stone would require to start from the moon at an initial velocity 8,292 feet per second; then proceeding downward with increasing speed, it would arrive on the earth with a [{539}] of 35,000 feet per second. But frequent measurements have shown that the actual rate of aërolites averages 114,000 feet, or about twenty-one miles and a half per second, they were approved by these curious and most elaborate calculations to have come from a fire greater distance than that of our satellite. It is but fair to add that the question of initial velocity, on which the whole value value of this so-called "ballistic problem" depends, was investigative by three other eminent geometricians, Biot, Laplace, and Poisson, who during ten or twelve years were independently engaged is calculation. Biot's estimate was 8,282 feet in the second; Laplace, 7,862; and Poisson, 7,585—results all approximating very closely with those stated by Olbers.