Chapter XVI: Part 16

The bolides, or fire-balls, and falling stars, so striking an example of which is given above, are of all sizes, from a small shooting-star of the fifth magnitude, to a cone or cylinder of two or three miles in diameter. They differ in consistency as much as in dimensions, and in color as much as in either. Occasionally, they are a subtile, luminous and pellucid vapor; and sometimes a compact ball, or globe, as though the materials of which they are formed, were more condensed and concentrated. Not unfrequently they have been found to consist of both, and consequently to assume a comet-like appearance, with a nucleus or compact substance in the center, or toward the center, and a long, thin, pellucid or luminous main, or tail, sweeping on each side. They are sometimes of a pale white light; at others, of a deep igneous crimson; and, occasionally iridescent and vibratory. The rarer meteors appear frequently to vanish on a sudden, as though abruptly dissolved or extinguished in the atmospheric medium, their flight being accompanied by a hissing sound, and their disappearance by an explosion. The most compact of them, or the nuclei of those which are rarer, have often descended to the surface of the earth, and with a force sufficient to bury them many feet under the soil; generally exhibiting marks of imperfect fusion and considerable heat. The substance is, in these cases, for the greater part metallic; but the ore of which they consist is not anywhere to be found, in the same constituent proportions, in the bowels of the earth. Under this form the projected masses are denominated aerolites, or meteoric stones.

It may not be uninteresting to preface a succinct account of the most surprising of these meteors, by a notice of the hypotheses which have been imagined concerning them; however justly the learned Humboldt may have concluded, in the words of the extracts given above, that we are still “as ignorant on this subject as men were in the days of Anaxagoras.” Sir J. Pringle contended, with other philosophers, that they are revolving bodies, or a kind of terrestrial planets. Doctor Halley conjectured them to consist of combustible vapors, accumulated and formed into concrete bodies on the outskirts, or extreme regions of the atmosphere, and to be suddenly set on fire by some unknown cause; an opinion which, with little difference, has been since entertained by Sir W. Hamilton and Dr. King. Dr. Blagdon regarded them altogether as electrical phenomena. M. Izarn believed them to consist of volcanic materials, propelled into the atmosphere in the course of explosions of great violence. M. Chladni supposed them to be formed of substances existing exteriorly to the atmosphere of the earth and other planets, which have never incorporated with them, and are found loose in the vast ocean of space, being there combined and inflamed by causes unknown to us. Lastly, another and rather wild hypothesis is, that the whole, or at least the more compact division of these meteors, are made up of materials thrown from immense volcanoes in the moon. This hypothesis, which was started by M. Olbers, in 1795, has been since very plausibly supported by the celebrated Laplace, but does not apply to the smaller and less substantial meteors, named shooting-stars. Hence these philosophers derive the latter phenomena from some other cause, as electricity, or terrestrial exhalations; and observe, in support of the distinction they find it necessary to make, that shooting-stars must be of a different nature from fire-balls, since they sometimes appear to ascend as well as to fall. This observation has been especially dwelt on by Messrs. Chladni and Benzenberg, both of them favorably noticed, as accurate observers, by Humboldt.

By far the most plausible and satisfactory theory, however, is one somewhat like that of Dr. Halley, which may be illustrated thus. If a stick of wood, after being covered over night in the hot ashes, so as to become in part or wholly charred, be taken out in the morning, and waved back and forth in the air, every one has noticed that it will send forth sparks by hundreds and thousands. Now the more modern theory as to these aerolites, or falling-stars, is, that they are thrown off from small, opaque, planetary bodies, revolving in space, which when they come within the atmosphere of the earth, are heated from their rapid motion through it, and throw off small heated portions, like the sparks from the waving brand. And this theory is confirmed by the fact, that, of late years, these meteoric showers have been annual, and always at about the same period of the year, as if the earth was then passing in that part of her orbit where she meets with the planetary bodies spoken of, and they come in contact with her atmosphere. In the volumes of the “American Journal of Science,” may be found abundant facts on this subject, and also the various theories started to account for the facts.

On the twenty-first of March, 1676, two hours after sunset, an extraordinary meteor was seen to pass over Italy. At Bononia, its greatest altitude in the south-south-east, was thirty-eight degrees; and at Sienna, fifty-eight degrees toward the north-north-east. In its course, which was from east-north-east to west-south-west, it passed over the Adriatic sea, as if coming from Dalmatia. It crossed all Italy, being nearly vertical to Rimini and Savigniano, on the one side, and to Leghorn on the other: its perpendicular altitude was at least thirty-eight miles. At all the places near its course it was heard to make a hissing noise as it passed, like that of artificial fireworks. In passing over Leghorn, it gave a very loud report, like that of a cannon; immediately after which another sort of sound was heard, like the rattling of a deeply loaded wagon passing over the stones, which continued for several seconds. The professor of mathematics at Bononia, calculated the apparent velocity of this surprising meteor at not less than one hundred and sixty miles in a minute of time, which is above ten times as swift as the diurnal rotation of the earth under the equinoctial, and not many times less than that with which the annual motion of the earth about the sun is performed. It there appeared larger than the moon in one diameter, and above half as large again in the other; which, with the given distance of the eye, made its real smaller diameter above half a mile, and the larger one in proportion. It is, therefore, not surprising, that so great a body, passing with such an amazing velocity through the air, however rarefied it may be in its upper regions, should occasion so loud a hissing noise as to be heard at such a distance. It finally went off to sea toward Corsica.

Two luminous meteors of great magnitude were noted at Leipsic within the space of six years. On the twenty-second of May, 1680, about three in the morning, the first of these was seen, to the great terror of the spectators, descending in the north, and leaving behind it a long white streak where it had passed. As the same phenomena was witnessed in the north-north-east at Haarburg, and also at Hamburg, Lubeck and Stralsund, all of which places are about a hundred and fifty English miles from Leipsic, it was concluded that this meteor was exceedingly high above the earth. The second meteor was still more terrific. On the ninth of July, 1686, at half past one in the morning, a fire-ball with a tail was observed in eight and a half degrees of Aquarius, and four degrees north, which continued nearly stationary for seven or eight minutes, with a diameter nearly equal to half the moon’s diameter. At first, its light was so great that the spectators could see to read by it; after which it gradually disappeared. This phenomenon was observed at the same time in several other places, more especially at Schlaitza, a town distant from Dantzic forty English miles toward the south, its altitude being about six degrees above the southern horizon. At Leipsic it was estimated to be distant not more than sixty English miles, and to be about twenty-four miles perpendicular above the horizon, so that it was at least thirty miles high in the air.

A very extraordinary meteor, which the common people called a flaming sword, was first seen at Leeds, in Yorkshire, on the eighteenth of May, 1710, at a quarter after ten at night. Its direction was from south to north: it was broad at one end, and small at the other; and was described by the spectators as resembling a trumpet, moving, with the broad end foremost. The light was so sudden and intense, that they were startled at seeing their own shadows, when neither sun nor moon shone upon them. This meteor was, in its course, seen not only in Yorkshire and Lancashire, but also in the counties of Nottingham and Derby, notwithstanding which, each of those who observed it, although so many miles distant from each other, fancied it fell within a few yards of him. In disappearing, it presented bright sparklings at the small end.

A blazing meteor was, on the nineteenth of March, 1719, seen in every part of England. In the metropolis, about a quarter after eight at night, a sudden powerful light was perceived in the west, far exceeding that of the moon, which then shone very bright. The long stream it gave out appeared to be branched about the middle; and the meteor, in its course, turned pear-fashioned, or tapering upward. At the lower end it came at length to be larger and spherical, although not so large as the full moon. Its color was whitish, with an eye of blue of a most vivid, dazzling luster, which seemed in brightness very nearly to resemble, if not to surpass, that of the body of the sun in a clear day. This brightness obliged the spectator to turn his eyes several times from it, as well when it was a stream, as when it was pear-fashioned and a globe. It seemed to move, in about half a minute or less, about the length of twenty degrees, and to disappear about as much above the horizon. Where it had passed, it left behind a track of a cloudy or faint reddish-yellow color, such as red-hot iron or glowing coals have: this continued more than a minute, seemed to sparkle, and kept its place without falling. This track was interrupted, or had a chasm toward its upper end, at about two-thirds of its length. No explosion was heard; but the place where the globe of light had been, continued for some time after it was extinct, of the same reddish-yellow color with the stream, and at first sparks seemed to issue from it, such as proceed from red-hot iron beaten out on an anvil.

It was agreed by all the spectators in the capital, that the splendor of this meteor was little inferior to that of the sun. Within doors the candles did not give out any light; and in the streets, not only all the stars disappeared, but the moon, then nine days old, and high near the meridian, the sky being very clear, was so far effaced as scarcely to be seen: it did not even cast a shade, where the beams of the meteor were intercepted by the houses; so that, for a few seconds of time, there was in every respect, a resemblance of perfect day.

The perpendicular hight of this surprising meteor was estimated at sixty-four geometrical miles; and it was computed to have run about three hundred of these miles in a minute. It was seen, not only in every part of Great Britain and Ireland, but likewise in Holland, in the western parts of Germany, in France and in Spain, nearly at the same instant of time. The accounts from Devonshire, Cornwall, and the neighboring counties, were unanimous in describing the wonderful noise which followed its explosion. It resembled the report of a large cannon, or rather of a broadside at some distance, which was soon followed by a rattling noise, as if many small arms had been promiscuously discharged. This tremendous sound was attended by an uncommon tremor of the air; and everywhere in those counties, not only the windows and doors of the houses were sensibly shaken, but, according to several of the reports, even the houses themselves, beyond the usual effect of cannon, however near.

On the eleventh of December, 1741, at seven minutes past one in the afternoon, a globe of fire, somewhat larger than the horizontal full moon, and as bright as the moon appears at any time when the sun is above the horizon, was seen at Peckham, in Surrey, in a south-south-east direction, moving toward the east with a continued equable motion, and leaving behind it a narrow streak of light, whiter than the globe itself, throughout its whole course. Toward the end it appeared less than at the beginning of its motion; and within three or four seconds suddenly vanished. Its apparent velocity was nearly equal to half the medium velocity of the ordinary meteors called falling or shooting stars; and its elevation, throughout the whole of its course, about twenty degrees above the horizon.

On the eighteenth of August, 1783, an uncommon meteor was seen in several parts of Great Britain, as well as on the continent. Its general appearance was that of a luminous ball, which, rising in the north-north-east, nearly of a globular form, became elliptical, and gradually assumed a tail as it ascended. In a certain part of its course it underwent a remarkable change, which might be compared to bursting, and which, it ought to be observed, has been since frequently noticed in the passage of the aerolites, or meteoric stones, particular mention of which will be made hereafter. After this it no longer proceeded as an entire mass, but was apparently divided into a great number, or cluster of balls, some larger than others, and all carrying a tail, or leaving a train behind. Under this form, it continued its course with a nearly equable motion, dropping or casting off sparks, and yielding a prodigious light, which illumined all objects to a surprising degree; until, having passed the east, and verging considerably to the southward, it gradually distended, and was at length lost to the sight. The time of its appearance was sixteen minutes past nine in the evening, mean time of the meridian of London, and it continued visible about half a minute.

This beautiful meteor having been seen in Shetland, and in the northern parts of Scotland, ascending from the north, and rising like the planet Mars, little doubt was entertained of its course having commenced beyond the furthest extremity of Great Britain, somewhere over the northern ocean. Having passed over Essex and the straits of Dover, it probably entered the continent not far from Dunkirk, where, as well as at Calais and Ostend, it was thought to be vertical. Still holding on its course to the southward, it was seen at Brussels, at Paris, and at Nuits in Burgundy; insomuch that there was sufficient proof of its having traversed thirteen or fourteen degrees of latitude, describing a track of at least one thousand miles over the surface of the earth; a length of course far exceeding the extent of what had been then ascertained of any similar phenomenon.

During the passage of this meteor over Brussels, the moon appeared quite red, but soon recovered its natural light. The results of several observations give it an elevation of more than fifty miles above the surface of the earth, in a region where the air is at least thirty thousand times rarer than here below. Notwithstanding this great elevation, the fact of a report having been heard some time after it disappeared, rests on the testimony of too many witnesses to be controverted. It was compared to the falling of some heavy body in a room above stairs, or to the discharge of one or more large cannon at a distance: this report was loudest in Lincolnshire and the adjacent counties, and also in the eastern parts of Kent.

Supposing the transverse diameter of this meteor to have subtended an angle of thirty minutes when it passed over the zenith, and that it was fifty miles high, it must have been almost half a mile across. The tail sometimes appeared ten or twelve times longer than the body; but most of this was train, and the real elongation behind seems seldom to have exceeded twice or thrice its transverse diameter; it consequently was between one and two miles in length. Now if the cubical contents be considered, for it appeared equally round and full in all directions, such an enormous mass must afford just matter of astonishment, when the extreme velocity with which it moved is considered. This velocity, agreeably to the observations of Sir William Herschel and several other astronomers, could not have been less than twenty miles in a second, exceeding that of sound above ninety times, and approaching toward that of the earth in her annual orbit. At such a rate it must have passed over the whole island of Great Britain in less than half a minute, and would, in the space of less than seven minutes, have traversed the whole diameter of the earth!

On the fourth of October, of the above year, 1783, two meteors were seen in England. The first, at three in the morning, on account of the early hour, was witnessed by but few spectators, who represented it as rising from the north to a small altitude, and then becoming stationary with a vibratory motion, and an illumination like daylight: it vanished in a few moments, leaving a train behind. This sort of tremulous appearance has been noticed in other meteors, as well as their continuing stationary for some time, either before they begin to shoot, or after their course is ended. The second of these meteors appeared at forty-three minutes past six in the evening, and was much smaller, and also of much shorter duration, than the one seen in August. It was first observed to the north, like a stream of fire, similar to that of the common shooting-stars, but large; and having proceeded some distance under this form, suddenly burst out into that intensely bright bluish light, peculiar to such meteors, which may be most aptly compared to the blue lights of India, or to some of the largest electrical sparks. The illumination was very great; and on that part of its course where it had been so bright, a dusky red streak or train was left, which remained visible about a minute, and was thought by some gradually to change its form. Except this train, the meteor had not any tail, but was nearly of a round body, or, perhaps, somewhat elliptical. After moving not less than ten degrees in this bright state, it became suddenly extinct, without any appearance of bursting or explosion.

AEROLITES.

These phenomena, otherwise entitled meteoric stones, have been ascertained, by recent observations, to be connected with the bolides, or fire-balls, described above. Scoriaceous masses have frequently been either actually seen to fall at the time of the disappearance of the latter, or have been found soon after on the surface of the earth. Most of the stones which have fallen from the atmosphere, have been preceded by the appearance of luminous bodies, or meteors. These meteors burst with an explosion, and then the shower of stones falls to the earth. Sometimes the stones continue luminous till they sink into the earth; but most commonly their luminousness disappears at the time of their explosion. These meteors move in a direction nearly horizontal, and seem to approach the earth before they explode.

The stony bodies, when found immediately after their descent, are always hot. They commonly bury themselves some depth under ground. Their size differs, from fragments of a very inconsiderable weight, to masses of several tuns. They usually approach the spherical form, and are always covered with a black crust; in many cases they smell strongly of sulphur. The black crust consists chiefly of oxyd of iron; and from several accurate analyses of these stones, the following important inferences have been drawn: that not any other bodies have as yet been discovered on our globe which contain the same ingredients; and that they have made us acquainted with a species of pyrites not formerly known, nor anywhere else to be found.

The ancients were not unacquainted with these meteoric stones, a shower of which is reported by Livy to have fallen at Rome under the consulate of Tullus Hostilius, and another under that of C. Martius and M. Torquatus. Pliny relates that a shower of iron (for thus he designates these stones) fell in Lucania, a year before the defeat of Crassus, and likewise speaks of a very large stone which fell near the river Negos, in Thrace. In the chronicle of Count Marcellin, there is an account of three immensely large stones having fallen in Thrace, in the year 452 before the advent of Christ.

To proceed to more modern and well authenticated instances of the fall of aerolites. On the seventh of November, 1492, a little before noon, a dreadful thunder-clap was heard at Ensisheim, in Alsace, instantly after which a child saw a huge stone fall on a field newly sown with wheat. On searching, it was found to have penetrated the earth about three feet, and weighed two hundred and sixty pounds, making its size equal to a cube of thirteen inches the side. All the contemporary writers agree in the reality of this phenomenon, observing that, if such a stone had before existed in a plowed land, it must have been known to the proprietor. The celebrated astronomer Gassendi relates an instance of an aerolite descent of which he was himself an eye-witness. On the twenty-seventh of November, 1627, the sky being clear, he saw a burning stone fall on Mont Vasir, in the south-east extremity of France, near Nice. While in the air, it seemed to be about four feet in diameter, was inclosed in a luminous circle of colors like a rainbow, and in its fall produced a sound like the discharge of cannon. It weighed fifty-nine pounds, was very hard, of a dull metallic color, and had a specific gravity considerably greater than that of marble. In the year 1672, two stones fell near Verona, in Italy, the one weighing three hundred, the other two hundred pounds. This phenomenon was witnessed in the evening, by three or four hundred persons. The stones fell, with a violent explosion, in a sloping direction, and in calm weather. They appeared to burn, and plowed up the ground. Paul Lucas, the traveler, relates that when he was at Larissa, a town of Greece, near the gulf of Salonica, a stone weighing seventy-two pounds, fell in the vicinity. It was observed to come from the northward, with a loud hissing noise, and seemed to be enveloped in a small cloud, which exploded when the stone fell. It looked like iron dross, and smelt of sulphur. In September, 1753, several stones fell in the province of Bresse, to the west of Geneva: one in particular fell at Pont de Vesle, and another at Liponas, places nine miles distant from each other. The sky was clear, and the weather warm. A loud noise, and a hissing sound, were heard at those two places, and for several miles round, on the fall of these stones, which exactly resembled each other, were of a darkish, dull color, very ponderous, and manifesting on their surface that they had suffered a violent degree of heat. The largest weighed about twenty pounds, and penetrated about six inches into the plowed ground; a circumstance which renders it highly improbable that they could have existed there before the explosion. This phenomenon has been described by the astronomer Delalande, whose strict inquiries on the spot enabled him to testify the truth of the circumstances he relates. In the year 1768, three stones were presented to the French Academy of Sciences, which had fallen in different parts of France; one at Luce, in the Maine; another at Aire, in Artois; and the third in Cotentin. They were all externally of the same identical appearance; and on the former of them a particular report was drawn up by Messrs. Fougeraux, Cadet and Lavoisier. This report states, that on the eighteenth of September, 1768, between four and five in the afternoon, there was seen, near the above village of Luce, a cloud in which a short explosion took place, followed by a hissing noise, but without any flame. The same sound was heard by several persons about ten miles from Luce; and, on looking up, they perceived an opaque body describe a curve in the air, and fall on a piece of green turf near the high road. They immediately ran to the spot, where they found a kind of stone, half-buried in the earth, extremely hot, and weighing about seven pounds and a half.

In the particular instance now to be cited, very distinct traces were left to show the progress of aerolites through the air. During the explosion of a meteor near Bordeaux, on the twentieth of August, 1789, a stone, in diameter about fifteen inches, fell through the roof of a cottage, and killed a herdsman and some cattle. Part of this stone is now in the Greville museum, and part in the museum of Bordeaux. On the twenty-fourth of July, 1790, between nine and ten at night, a shower of stones fell near Agen, in Guienne, near the south-west angle of France. First a luminous ball of fire was seen traversing the atmosphere with great rapidity, and leaving behind it a train of light which lasted about fifty seconds; soon after this a loud explosion was heard, and sparks were seen to fly off in all directions. This was soon after followed by the fall of stones, over a considerable extent of ground, and at various distances from each other. These were all alike in appearance, but of many different sizes, the greater number weighing about two ounces, but many a vast deal more. Some fell with a hissing noise, and entered the ground; but the smaller ones remained on the surface. The only damage done by this shower of stones was, that they broke the tiles of several houses, in falling on which they had not the sound of hard and compact substances, but of matter in a soft, half-melted state. Such as fell on straws adhered to them, and could not be readily separated; a manifest proof that they were in a state of fusion.

On the eighteenth of December, 1795, several persons near the house of Captain Topham, in Yorkshire, heard a loud noise in the air, followed by a hissing sound, and soon after felt a shock, as if a heavy body had fallen to the ground at a little distance from them. In reality, one of them saw a huge stone fall to the earth, at the distance of eight or nine yards from the place where he stood. When he first observed it, it was seven or eight yards above the ground; and in its fall it threw up the mold on every side, burying itself twenty-one inches in the earth. This stone on being dug up, was found to weigh fifty-six pounds. On the seventeenth of March, 1798, a body, burning with an intense light, passed over the vicinity of Ville Franche, on the Saone, near Lyons, accompanied by a hissing sound, and leaving behind a luminous track. This phenomenon exploded with a great noise, about twelve hundred feet from the ground, and one of the splinters, still luminous, having been observed to fall in a neighboring vineyard, was traced. It was about a foot in diameter, and had penetrated twenty inches into the ground. On the fourth of July, 1803, a ball of fire struck a public house at East Norton, in Oxfordshire. The chimney was thrown down, the roof partly torn off, the windows shattered to atoms, and the dairy, &c., converted into a heap of rubbish. It was of considerable magnitude, and, on coming in contact with the house, exploded with great noise, and a very oppressive sulphureous smell. Several fragments of stones were found on the spot, having a surface of a dark color, and varnished, as if in a state of fusion, with numerous globules of a whitish metal, combining sulphur and nickel. The indentures on these surfaces render it probable that the ball was soft when it descended; and it was obviously in a state of fusion, as the grass was burned where the fragments fell. The motion of the fire-ball, while in the air, was very rapid, and apparently parallel to the horizon.

The latest remarkable fall of aerolites in Europe, of which there is a distinct account, was in the vicinity of Laigle, in Normandy, early in the afternoon of the twenty-sixth of April, 1812. A fiery globe of a very brilliant splendor, which moved in the air with great rapidity, was followed in a few seconds by a violent explosion, which lasted five or six minutes, and was heard to the extent of more than thirty leagues in every direction. Three or four reports, like those of a cannon, were followed by a discharge resembling a fire of musketry, after which a dreadful rumbling was heard like the beating of a drum. The air was calm, and the sky serene, with the exception of a few clouds, such as are frequently observed. The noise proceeded from a small cloud of a rectangular form, the largest side being in a direction from east to west. It appeared motionless all the time the phenomenon lasted; but the vapor of which it was composed was projected momentarily from the different sides by the effect of the successive explosions. This cloud was about half a league to the north-north-east of the town of Laigle, and was at so great an elevation, that the inhabitants of two hamlets, a league distant from each other, saw it at the same time over their heads. In the whole canton over which this cloud hovered, a hissing noise, like that of a stone discharged from a sling, was heard; and a multitude of meteoric stones were seen to fall at the same time. The district in which they fell forms an elliptical extent of about two leagues and a half in length, and nearly one in breadth; the greatest dimension being in a direction from south-east to north-west, forming a declination of about twenty-two degrees. This direction, which the meteor must have followed, is exactly that of the magnetic meridian; which is a remarkable fact. The number of these stones was reckoned to exceed three thousand; and the largest of them weighed nearly twenty pounds. They were friable some days after their fall, and smelt strongly of sulphur. They subsequently acquired the degree of hardness common to this kind of stones.

While, in Europe, these phenomena thus strongly confirmed the long exploded idea of the vulgar, that many of the luminous meteors observed in the atmosphere, are masses of ignited matter, an account of one of precisely the same description was received from the East Indies. On the nineteenth of December, 1798, at eight in the evening, a large fire-ball, or luminous meteor, was seen at Benares, and at several places in its vicinity. It was attended by a loud rumbling noise; and, about the same time, the inhabitants of Krakhut, fourteen miles from Benares, saw the light, heard what resembled a loud thunder-clap, and, immediately after, the noise of heavy bodies falling around them. Next morning the mold in the fields was found to have been turned up in many spots; and unusual stones of various sizes, but of the same substances, were picked from the moist soil, generally at a depth of six inches. One stone fell through the roof of a hut, and buried itself in the earthen floor.

From these multiplied evidences it is proved that, in various parts of the world, luminous meteors have been seen moving through the air with surprising rapidity, in a direction more or less oblique, accompanied with a noise, commonly like the whizzing of cannon-balls, followed by explosion, and the fall of hard, stony, or semi-metallic masses in a heated state. The constant whizzing sound; the fact of stones being found, like each other, but unlike all others in the vicinity, at the spots toward which the luminous body, or its fragments, had been seen to move; the scattering or plowing up of the soil at those spots, always in proportion to the size of the stones; the concussion of the neighboring ground at the same time; and especially, the impinging of the stones on bodies somewhat above the earth, or lying loose on its surface; all these are circumstances perfectly well authenticated in these reports, proving that such meteors are usually inflamed hard masses, descending rapidly through the air to the earth.

AURORA BOREALIS AND AURORA AUSTRALIS.

These splendid meteors are generally considered as the result of a combination of the two powers of magnetism and electricity. When the _light_, or _aurora_, appears chiefly in the north part of the heavens, it is called the _aurora borealis_, or northern lights; and when chiefly in the south part, the =aurora australis=, or southern lights. Where the coruscation is more than ordinarily bright and streaming, which, however, seldom occurs in the north, it is denominated =lumen boreale=; and where these streams have assumed a decided curvature, like that of the rainbow, they are distinguished by the name of luminous arches.

The aurora is chiefly visible in the winter season, and in cold weather. It is usually of a reddish color, inclining to yellow, and sends out frequent coruscations of pale light, which seem to rise from the horizon in a pyramidal, undulating form, shooting with great velocity up to the zenith. It never appears near the equator; but of late years has frequently been seen toward the south pole. The =aurora borealis= has appeared at some periods more frequently than at others. This phenomenon was so rare in England, or so little regarded, that its appearance was not recorded in the English annals between a remarkable one observed on the fourteenth of November, 1554, and a very brilliant one on the sixth of March, 1716, and the two succeeding nights, but which was much strongest on the first night. Hence it may be inferred, that the state of either the air or earth, or perhaps of both, is not at all times fitted for its production.

The extent of these appearances is surprisingly great. The very brilliant one referred to above was visible from the west of Ireland to the confines of Russia, and the east of Poland, extending over, at the least, thirty degrees of longitude, and, from about the fiftieth degree of latitude, over almost all the northern part of Europe. In every place, it exhibited, at the same time, the same wonderful features. The elevation of these lights is equally surprising: an =aurora borealis= which appeared on the sixteenth of December, 1737, was ascertained, by means of thirty computations, to have an average hight from the earth of one hundred and seventy-five leagues, equal to four hundred and sixty-four English miles.

Captain Cook, in his first voyage round the world, observed that these coruscations are frequently visible in southern latitudes. On the sixteenth of September, 1770, he witnessed an appearance of this kind about ten o’clock at night, consisting of a dull, reddish light, and extending about twenty degrees above the horizon. Its extent was very different at different times, but it was never less than eight or ten points of the compass. Rays of light, of a brighter color, passed through and without it; and these rays vanished and were renewed nearly in the same time as those in the =aurora borealis=, but had little or no vibration. Its body bore south-south-east from the ship, and continued, without any diminution of its brightness, till twelve o’clock, when the observers retired. The ship was at this time within the tropic of Capricorn.

On the seventeenth of February, 1773, during his second voyage, Captain Cook speaks of a beautiful phenomenon that was observed in the heavens. “It consisted of long columns of a clear white light, shooting up from the horizon to the eastward, almost to the zenith, and spreading gradually over the whole southern parts of the sky. These columns even sometimes bent sideways at their upper extremity; and, although in most respects similar to the northern lights, (the =aurora borealis= of our hemisphere,) yet differed from them in being always of a whitish color; whereas ours assume various tints, especially those of a fiery and purple hue. The stars were sometimes hidden by, and sometimes faintly to be seen through the substance of these southern lights, =aurora australis=. The sky was generally clear when they appeared, and the air sharp and cold, the mercury in the thermometer standing at the freezing-point; the ship being then in fifty-eight degrees south.” On six different nights of the following month (March) the same phenomenon was observed.

LUMEN BOREALE, OR STREAMING LIGHTS.

On the eighth of October, 1726, uncommon streams of light were exhibited in every part of the heavens, about eight o’clock in the evening. They were seen throughout England, as well as in the southern parts of Europe. They were mostly pointed, and of different lengths, assuming the appearance of flaming spires or pyramids; some again were truncated, and reached but half-way; while others had their points reaching up to the zenith, or near it, where they formed a sort of canopy, or thin cloud, sometimes red, sometimes brownish, sometimes blazing as if on fire, and sometimes emitting streams all around it. This canopy was manifestly formed by the matter carried up by the streaming on all parts of the horizon. It sometimes seemed to ascend with a force, as if impelled by the impetus of some explosive agent below; and this forcible ascent of the streaming matter gave a motion to the canopy, and sometimes a gyration, like that of a whirlwind. This was manifestly caused by the streams striking the outer part of the canopy; but if they struck the canopy in the center, all was then confusion. The vapors between the spires, or pyramids, were of a blood-red color, which gave those parts of the atmosphere the appearance of blazing lances and bloody-colored pillars. There was also a strange commotion among the streams, as if some large cloud or other body was moving behind and disturbing them. In the northern and southern parts the streams were perpendicular to the horizon; but in the intermediate points they seemed to decline more or less in one way or the other, or rather to incline toward the meridian. Several persons declared, that in the time of the streaming, they heard a hissing, and in some places a crackling noise, like that which is reported to be often heard in earthquakes.

At Naples, on the sixteenth of December, 1737, early in the evening, a light was observed in the north, as if the air was on fire, and flashing. Its intenseness gradually increasing, about seven o’clock it spread to the westward. Its greatest hight was about sixty-five degrees. Its extremities were unequally jagged and scattered, and followed the course of the westerly wind; so that for a few hours it spread considerably wider, yet without ever extending to the zenith. About eight o’clock, a very regular arch, of a parabolic figure, was seen to rise gently to two degrees of rectangular elevation, and to twenty degrees of horizontal amplitude. At ten the intenseness of the color disappeared; and by midnight not any traces of this phenomenon were left. It was seen throughout Italy, as the subsequent accounts will show. At Padua, on the appearance of this extraordinary meteor, the air was calm, and the barometer remarkably high. At five in the afternoon a blackish zone, with its upper limb of a sky-color, appeared near the horizon; and above this zone was another, very luminous, resembling the dawn pretty far advanced. The highest zone was of a red, fiery color. A little after six o’clock, the upper parts of these zones emitted an abundance of red streamings, or rays; their vivid color being occasionally intermixed with whitish and dark spots. In a few seconds after, there issued from the west, a red and very bright column, which ascended to the third part of the heavens, and a little after became curved like a rainbow. At half past eight, almost instantaneously, the bright zone, from eight degrees west to fifty degrees east, became more vivid, and rose higher; and above this appeared another and larger one, of a red, fiery color, with several successive streamings tending upward, and exceeding sixty degrees of altitude; the western part having assumed the form of a thin cloud. At midnight these splendid lights disappeared entirely. At Bononia, this surprising meteor spread to such an extent as to occupy about one hundred and forty degrees of the heavens. Its light was so vivid that houses could be distinguished, at eight in the evening, at a very considerable distance; and these were so reddened, that many persons thought there was a fire in the neighborhood. At that time the aurora formed itself into a concave arch toward the horizon; and in half an hour, at its eastern limit, a pyramid was displayed, of a more intense color toward the north, from the center of which there shot up vertically a streak of light, between a white and a yellow color. A very dark, narrow cloud crossed the whole phenomenon, and terminated in the pyramid. At the upper part, a very considerable tract of the heavens was enlightened by a very vivid red light, which was interrupted by several streaks or columns of a bright yellowish light. These streamings shot up vertically, and parallel to each other, the narrow cloud seeming to serve them as a basis. Under the cloud there issued forth two tails of a whitish light, hanging downward on a basis of a weak red, and seeming to kindle and dart the light downward. A white streak, which passed across these two tails, and extended from one end of the phenomenon to the other, in a position almost parallel to the above-mentioned cloud, gave a splendid effect to the whole. This surprising and beautiful meteor disappeared a short time after nine o’clock; but an abundance of falling stars were afterward seen in the south.

Similar observations were made at Rome; but in Great Britain, where this phenomenon was likewise seen, different appearances were displayed. At Edinburgh, at six in the evening, the sky appeared to be in flames. An arch of red light reached from the west, over the zenith, to the east, its northern border being tinged with a color approaching to blue. This aurora did not first form in the north, as usually happens, and after forming an arch there, rise toward the zenith; neither did the light shiver, and spread itself, by sudden jerks, over the hemisphere, as is common, but it gradually and gently stole along the face of the heavens, till it had covered the whole hemisphere: this alarmed the vulgar, and was indeed a strange sight. At Rosehill, in Sussex, it appeared as a strong and very steady light, nearly of the color of red ocher. It did not dart or flash, but kept a steady course against the wind, which blew fresh from the south-west. It began in the north-north-west, in the form of a pillar of light, at a quarter past six in the evening: in about ten minutes a fourth part of it divided from the rest, and never joined again. In ten minutes more it described an arch, but did not join at the top; and at seven o’clock it formed a bow, disappearing soon after. It was lightest and reddest at the horizon, and gave as much light as a full moon.

LUMINOUS ARCHES.

In the month of March, 1774, a very beautiful luminous arch was seen at Buxton. It was white, inclining to yellow: and its breadth in the crown was apparently equal to that of the rainbow. As it approached the horizon, each leg of the arch became gradually broader. It was stationary and free from any sensible coruscations. Its direction was from north-east to south-west; and its crown or most elevated part, not far from the zenith. This phenomenon lasted about half an hour.

The grandest spectacle of this kind which appears to have been seen in Great Britain, was observed at Leeds, in Yorkshire, on the twelfth of April, 1783, between the hours of nine and ten at night. A broad arch of a bright pale yellow, and having an apparent breadth of about fifteen degrees, arose in the heavens, and passed considerably south of the zenith. Such was its varied density, that it appeared to consist of small columns of light, having a sensible motion. After about ten minutes, innumerable bright coruscations shot out at right angles from its northern edge, elongating themselves more and more till they had nearly reached the northern horizon. As they descended, their extremities were tipped with an elegant crimson, such as is produced by the electric spark in an exhausted tube. After some time this beautiful northern light ceased to shoot, and, forming a line of bright yellow clouds, which extended horizontally about the fourth of a circle, its greatest portion, which darted from this arch toward the north, as well as the cloudlike and more stationary aurora, became so dense as to hide the stars from view. The moon was eleven days old, and shone brightly during this scene, but did not eclipse the splendor of these coruscations. The wind was in the north, a little inclined to the east. A similar phenomenon was observed at Leeds on the twenty-sixth of the same month. From a mass or broad column of light in the west, issued three luminous arches, each of which made a different angle with the horizon. They had not been viewed many minutes when they were rendered invisible by a general blaze of =aurora borealis=, which possessed the space just before occupied by these arches.

IGNES FATUI, OR MOCK FIRES.

These meteors, denominated by the vulgar, Will-with-a-wisp, and Jack-with-a-lantern, and at sea or on the coast, mariner’s lights, or St. Helmo’s fires, are now considered as real exhalations from the earth, produced by gas, vapor, or some other attenuated substance, emanating from vegetable, animal or mineral materials, and combined with the matter of light or heat, or both. Instead of being dense or solid, they are uniformly rare and subtile; and, instead of originating in the loftiest regions of the atmosphere, or beyond its range, are generated for the greater part in low, marshy plains or valleys. To the fearful and superstitious, they are a source of as much terror as the nobler and sublimer meteors which have just been contemplated; and it is probable that they have occasionally been the source of real and extensive damage, when in a state of actual combustion, and that they have still more frequently seduced a timid and benighted traveler into dangerous bogs and quagmires.

In Italy, in the Bolognese territory, they are so frequent, in the morassy grounds, that they are to be seen every night, some of them affording as much light as a kindled torch, and others not being larger than the flame of a candle, but all of them so luminous as to shed a luster on the surrounding objects. They are constantly in motion, but this motion is various and uncertain. They sometimes rise and at other times sink, sometimes suddenly disappearing, and appearing again in an instant in some other place. They usually hover about six feet from the ground, differing both in figure and size, and spreading out and contracting themselves alternately. Sometimes they break to appearance into two parts, soon after uniting again in one body, and at intervals float like waves, letting fall portions of ignited matter, like sparks from a fire. They are more frequently observed in winter than in summer, and cast the strongest light in rainy and moist weather. They are most friendly to the banks of brooks and rivers, and to morasses; but they are likewise seen on elevated grounds, where they are, however, of a comparatively diminutive size.

In the month of March, 1728, a traveler being in a mountainous road, about ten miles south of Bononia, perceived, as he approached the river Riovedere, between eight and nine in the evening, a light shining very brightly on some stones which lay on the banks. It was elevated about two feet above them; its figure describing a parallelopiped, more than a foot in length, and about six inches high, its longest side lying parallel to the horizon. Its light was so strong that he could distinguish by it very plainly a part of a neighboring hedge, and the water in the river. On a near approach, it changed from a bright red to a yellowish color, and on drawing still nearer, became pale; but when the observer reached the spot it vanished. On his stepping back, he not only saw it again, but found that the further he receded, the stronger and more luminous it became. This light was afterward seen several times, both in spring and autumn, precisely at the same spot, and preserving the same shape.

On the twelfth of December, 1776, several very remarkable =ignes fatui= were observed on the road to Bromsgrove, five miles from Birmingham, in England, a little before daylight. A great many of these lights were playing in an adjacent field, in different directions; from some of which there suddenly sprang up bright branches of light, somewhat resembling the explosion of a rocket, filled with many brilliant stars, if, in the case of the latter, the discharge be supposed to be upward, or vertical, instead of taking the usual direction. The hedge, and the trees on each side, were strongly illuminated. This appearance continued a few seconds only, when the =ignes fatui= played as before. The spectator was not sufficiently near to observe whether the apparent explosions were attended with any report.

In the month of December, 1693, between the twenty-fourth and thirtieth, a fiery exhalation, without doubt generated in the same way with the meteors described above, set fire to sixteen ricks of hay, and two barns filled with corn and hay, at the village of Hartech, in Pembrokeshire. It had frequently been seen before, proceeding from the sea, and in these instances lasted for a fortnight or three weeks. It not only fired the hay, but poisoned the grass, for the extent of a mile, so as to induce a distemper among the cattle. It was a weak blue flame, easily extinguished, and did not in the least burn any of the men who interposed their endeavors to save the hay, although they ventured, not only close to it, but sometimes into it. All the damage sustained happened constantly in the night.

Belonging to this class of meteors is the =draco volans=, a fiery exhalation, frequent in marshy and cold countries. It is most common in summer; and, although principally seen playing near the banks of rivers, or in boggy places, still it sometimes mounts up to a considerable hight in the air, to the no small terror of the amazed beholders. Its appearance is that of an oblong (sometimes roundish) fiery body, with a long tail. It is entirely harmless, frequently sticking to the hands and clothes of the spectators, without doing them the least injury.

SPECTER OF THE BROCKEN.

This is one of those curious and interesting atmospheric phenomena, or deceptions, which proceed from one common cause, an irregularity in the tenuity of the atmospheric fluid. This fluid is commonly of an homogeneous or equable tenuity, and consequently suffers the rays of the sun to penetrate it without any obstruction or change; but is at times irregular, and composed of parts of bodies of a denser medium than its general texture and constitution. Under these circumstances, the fluent ray, if it do not enter the denser medium in a direct or perpendicular line, will be either reflected, or refracted, or both; and the object surveyed through it, will assume a new, and, not unfrequently, a grotesque or highly magnified appearance.