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balls were seen even after the sun had arisen. The entire extent of the exhibition is not yet ascertained with precision, but it covered no inconsiderable portion of the earth's surface. It has been traced from the longitude of 61° in the Atlantic ocean, to longitude 100° in central Mexico, and from the North American lakes to the southern side of the Island of Jamaica. It was not seen, however, any where in Europe, nor in South America, nor in any part of the Pacific ocean yet heard from. Every where within the above named limits, the first appearance was that of fire-works of the most imposing grandeur, covering the entire vault of heaven with myriads of fire-balls resembling sky-rockets. On more attentive inspection it was seen, that the meteors exhibited three distinct varieties; the first, consisting of phosphoric lines, apparently described by a point; the second, of large fire-balls, that at intervals darted along the sky, leaving luminous trains which occasionally remained in view for a number of minutes, and, in some cases, for half an hour or more; the third, of undefined luminous bodies, which remained nearly stationary in the heavens for a long time. Those of the first variety were the most numerous, and resembled a shower of fiery snow driven with inconceivable velocity to the north of west. The second kind appeared more like falling stars, giving to many persons the impression that the stars were actually falling from the sky, a spectacle which was contemplated by the more unenlightened beholders with great amazement and terror. These fire-balls were occasionally of enormous size. Dr. Smith, of North Carolina, describes one which appeared larger than the full moon rising. "I was," says he, "startled by the splendid light in which the surrounding scene was exhibited, rendering even small objects quite visible."

One of the most remarkable circumstances attending this display was, that the meteors all seemed to emanate from one and the same point; that is, if their lines of direction had been continued backward, they would have met in the same point, southeast a little from the zenith. They set out at different distances from this point, and, following the arch of the sky, ran along the vault with immense velocity, describing in some instances an arc of 30° or 40° in less than four seconds. The trains which they left were commonly white, but were sometimes tinged with various prismatic colors. One ball (seen at New Haven, and supposed to have been identical with one described by various observers) that shot off in the northwest direction, and exploded a little northward of the star Capella, left, just behind the place of explosion, a phos phorescent train of peculiar beauty. The line of direction was at first nearly straight; but it soon began to contract in length, to dilate in breadth, and to assume the figure of a serpent drawing himself up, until it appeared like a small luminous cloud of vapor. This cloud was borne eastward (by the wind, as was supposed, which was blowing

gently in that direction) opposite to the course in which the meteor had proceeded, remaining in sight several minutes.

Of the third variety of meteors, the following are remarkable examples. At Poland, Ohio, a luminous body was distinctly visible in the northeast for more than an hour. It was very brilliant, in the form of a pruning-hook, and apparently twenty feet long, and eighteen inches broad It gradually settled towards the horizon, until it disappeared. At Niagara Falls, a large, luminous body, shaped like a square table, was seen nearly in the zenith, remaining for some time almost stationary, emitting large streams of light. At Charleston, S. C., a meteor of extraordinary size was seen to course the heavens for a great length of time, and then was heard to explode with the noise of a cannon.

The apparent radiant, or the point from which the meteors seemed to emanate, was observed, by those who fixed its position among the stars, to be in the constellation Leo. At New Haven it appeared in the bend of the sickle (a collection of stars in the breast of Leo), a little to the westward of the star Gamma Leonis. By observers at other places remote from each other, it was seen in the same constellation, although in different parts of it, a change of position supposed to be owing to the effect of parallax. An important observation, first published by the writer of this article, and since confirmed by the concurrent testimony of all the observers who remarked the position of the foregoing radiant point among the fixed stars, is, that this point was stationary among the stars, during the whole period of observation; that is, that it did not move along with the earth, in its diurnal revolution eastward, but aecompanied the stars in their apparent progress westward.

According to the testimony of by far the greater number of observers, the meteors were unaccompanied by any peculiar sound; but, on the other hand, such a sound, supposed to proceed from the meteors, was said to be distinctly heard by a few observers in various places. It is well known, however, that persons unaccustomed to making observations in the stillness of night, are apt, when listening at such times, to hear sounds which they associate with any remarkable phenomenon that happens to be present, although wholly unconnected with it. The question, therefore, whether any sound proceeded from the meteors, must rest, for its decision, on the circumstances of the case; such as the peculiarity of the sounds, and their uniformity as described by dif ferent observers. In the present case, the sounds supposed to have been heard by a few observers, are represented either as a hissing noise, like the rushing of a sky-rocket, or as slight explosions, like the bursting of the same bodies. These comparisons are thought to occur too uniformly, and in too many instances, to permit the supposition that they were either imaginary, or were derived from extraneous sources.

It is not held as a fact well established, that any substance reached

the ground which can be considered as a residuum or deposit from the meteors, although indications of such a substance were supposed to be discovered by different observers.

A remarkable change of weather from warm to cold, accompanied the meteoric shower, or immediately followed it. In all parts of the United States, this change was remarkable for its suddenness and intensity. In many places, the day preceding had been unusually warm for the season, but, before morning, a severe frost ensued, unparalleled for the time of year. Indeed, the seasons and atmospheric changes exhibited remarkable anomalies long after that period, a fact which it may be well to place on record to compare with future observations, although it may be impossible to decide, at present, whether or not these irregularities had any connection with the phenomena in question. Thus, at Michilimackinac, so uncommonly mild was the season throughout the latter part of November, and the whole of December, that the Indians made maple sugar during this month, and the contiguous lakes remained unfrozen as late as the 3d of January. At the same period, the season in the southwestern States, as far as New Orleans, was unusually cold. In most parts of New England, an uncommonly mild winter was succeeded by a remarkably cold and backward spring, requiring domestic fires to be kindled throughout the month of May, and frequently in the month of June. A succession of gales commenced about the time of the meteoric shower, first in the Atlantic Ocean, and afterwards in various parts of the United States, almost unequalled in this country for their frequency and violence.

In entering on the explanation of these mysterious phenomena, it is argued, in the first place, that the meteors had their origin beyond the limits of our atmosphere; that they, of course, did not belong to this earth, but to the regions of space exterior to it. All bodies near the earth, including the atmosphere itself, have a common motion with the earth round its axis from west to east; but the radiant point, that indicated the source from which the meteors emanated, followed the course of the stars from east to west; therefore it was independent of the earth's rotation, and consequently at a great distance from it, and beyond the limits of the atmosphere.

Having established this point, the next inquiry is, What is the height of the place whence the meteors proceeded; that is, the height of the meteoric cloud (so to speak) above the surface of the earth? If this cloud were not too distant from the earth to have a parallax, spectators remote from each other would refer it to different points in the heavens. If, for example, an observer at Boston marked the position of the cloud by a certain star, one in South Carolina would refer it to a point farther north, and one in Ohio would see it farther east. The former change of place is called parallax in declination, and the latter paral

lax in right ascension; and a parallax either way affords the means of estimating the height of the object above the surface of the earth, in the same manner as we estimate the height of a common cloud.

Now it has been ascertained that observations made in different latitudes indicated a corresponding parallax in declination, and these observations, being collected and carefully compared with each other, give an average distance from the surface of the earth of 2238 miles, as the height of the meteoric cloud. The anomalies, however, in regard to the corresponding differences of right ascension are such, that Mr. A. C. Twining is of the opinion, that the change of apparent position in the heavens in advancing from north to south, was owing to some other cause than parallax. We also consider this estimate of the distance of the meteoric cloud, as only an approximation, the best that can be deriv. ed from data that are imperfect and sometimes discordant; and regard it as probable, that the real source of the meteors was considerably more distant than the limit here assigned.

Material substances comparatively so near the earth as two or three thousand miles, would be strongly affected by the earth's gravity, and bodies constituted of exceedingly light materials (as the meteors will presently be shown to have been) would be readily attracted down to the earth from such a height. Gravity, therefore, being both a known and an adequate cause, is assigned as the force by which the meteors were drawn or impelled towards the earth; and hence it is inferred that they fell in parallel lines directed to the centre of the earth. This accounts for their apparent radiation from a common centre, as will be readily understood from the annexed representation.

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Let ABC represent the vault of the sky, the centre of which, D, being the place of the spectator. Let 1, 2, 3, &c., represent parallel lines directed towards the earth. A luminous body descending through the line DE, coincident with the axis of vision, would appear stationary all the while at 1'; a body descending the line marked 2, 2, would appear to describe the short arc 2', 2; and a body descending the line 3, 3, would appear to describe the longer are 3', 3. By con. sidering thus, the manner in which the arcs described on the celestial vault would appear, according as the meteor was nearer the axis of vision or more remote from it, we shall arrive at the following conclusions; that those meteors which fell nearer to the axis of vision, would seem to describe shorter arcs, and move slower, while those which were further from the same axis, would appear to describe longer arcs, and to move with greater velocity; that the meteors would all seem to radiate from a common centre, namely, the point where the axis of vision, DE, met the celestial vault; and that if any meteor chanced to move directly in the line of vision, it would be seen as a luminous body, stationary for a few seconds at the centre of radiation. All these conditions are in perfect accordance with the appearances of the meteors, as described by various observers.

Although it is doubtful, from the want of the requisite data, whether the source of the meteors, or the height of the meteoric cloud, has been accurately ascertained; yet the limit above estimated is confidently believed not to exceed the actual distance. According to the established laws of falling bodies, the inquiry is next instituted, chat velocity the meteors acould acquire in falling from a point 2238 miles above the earth to within fifty miles of its surface, this being considered as nearly the height of the atmosphere. The calculation gives nearly a velocity of four miles per second, as that with which the meteors entered the earth's atmosphere, a velocity more than ten times the maximum velocity of a cannon-ball, and about nineteen times that of sound. It must be recollected that the atmosphere diminishes in density very rapidly as we ascend from the earth, until at the height of fifty miles, it is so rare as hardly to oppose the least resistance to a body moving in it. It is well known that when air is suddenly compressed, a great quantity of heat is extricated from it. A little instrument is constructed on this principle for lighting tinder, by forcing down a solid piston upon a confined column of air in a small barrel. A spark is elicited, which ignites tinder at the bottom of the barrel. In the same manner, the meteors, on entering the atmosphere, produced a sudden and powerful compression of the air before them, thus extricating heat sufficient to produce in them an intense ignition, and, if they were combustible, to set them on fire.

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