teors, of all classes, is that of a very eminent observer, M. Quetelet, published in 1837; and again, with large additions, in 1841. There soon followed the catalogue of Mr. Herrick, in America, and that of M. Chasles, presented to the Académie des Sciences in 1841-containing much curious retrospective information, and particularly as to the recorded falls of shooting-stars. The latest catalogue is that by Professor Baden Powell-presented in series at the five last meetings of the British Association, and published in their Annual Reports. Professing to be merely a continuation of Quetelet's Catalogue, and to form a nucleus for future collection, it is, in truth, a most copious and valuable register of these phenomena, attesting-if any attestation were necessary-the equal zeal and ability of its author. We will not call it complete, because no record of these vagrant and fugitive appearances can be so. We do not, for instance, find noted in the Report for 1851 a very remarkable meteor, of which we ourselves witnessed the appearance and disruption on the 30th September, 1850, from the Observatory at Cambridge, in Massachussets; and which has been fully described by Mr. Bond, the distinguished astronomer of that university.* But many of these lacunæ will be filled up; and meanwhile the catalogue is ample enough to furnish an admirable basis for future observation and theory.

We have noted the frequent connexion of these igneous meteors with falling stones; and this is, in truth, the question of greatest interest regarding them. Are they always associated with some form of matter analogous to that of known aerolites, but which escapes detection, either by falling out of human sight, or by the passage forwards of the meteor in its orbit, without precipitation of its contents? Taking the question generally, we incline to answer at once in the affirmative. It must be admitted that stones have sometimes fallen from what seems to be a clear heaven; or with no other appearance than that of a small circular cloud suddenly forming in the sky. But these, as far as we know, are events of the daytime; and what is seen as a dark form under the light of the sun may appear a fiery globe in the darkness of night. If it be well proved in a few cases that these fire-balls exploding have thrown down stones upon the earth, the

The most striking circumstances in this meteor were, the long time (more than an hour) the nebulous light was visible after the explosion-the great distinctness of the nucleus, an elongated luminous space being projected, as it were, ahead of it-the perfectly cometary figure and aspect of the meteor a quarter of an hour after its first appearance, a fact strongly adverted to by Mr. Bond-and the rotary motion of the luminous elongation-amounting to nearly 90° within twenty minutes, and producing a sort of whorl, resembling some of the nebulæ so beautifully depictured from Lord Rosse's late observations.

presumption

presumption becomes strong that analogous meteorical elements. are present in all, whether precipitated or not. M. Saigey does not fully admit the relation of bolides and aerolites; but we believe the argument fairly to stand as we have stated it.

The subject of Shooting Stars (étoiles filantes) separates itself somewhat further from the phenomena already described, though still manifestly connected in various ways. The more important peculiarities here are the smaller size of these meteors; their infinitely greater frequency; the arcs they describe; their frequent occurrence in showers; and the observed periodicity in certain of these latter occurrences. The difference of magnitude is the least important of their characters; since we find every gradation of size, from the shooting scintilla of light to globes large as the moon. Those gradations, partially visible to any eye gazing into the depths of the sky on a clear night, are especially seen during the showers of stars just adverted to. The periodicity of some of these showers is the point of greatest interest in the inquiry ; a research still very imperfect, but which time is certain to complete, and probably at no distant period.

The common aspect of shooting stars needs no description. It was one of the earliest objects of science, as directed to them, to determine their heights, duration, and velocity; and on these points we owe much to the persevering labours of Brandes and Benzenburg; an ample narrative of whose observations is given in the French work before us. Begun as early as 1798, they were continued at intervals of time, and in different places, for a period of thirty-five years; Brandes dying in 1834, just after he had received the account of that prodigious fall of shooting stars in America, on the 12th and 13th November, which gave at once larger scope and better definition to all our views of these phenomena. To determine the points just mentioned, it was essential to have two observers at least, and a base of sufficient length for separate observation, Equally essential was it to assure the identity of the objects seen; for which recourse was had to the exact time of appearance, as well as to the apparent brilliancy, swiftness, and length of train of each star observed. Observation strictly simultaneous was needful to success; and this could only be got by knowing the precise difference of longitude between the stations. The base first taken, two leagues in length, proved too short to furnish the parallax required. In 1801 the inquiry was resumed, with the aid of two fresh observers; and four points were taken, the extremes of which, Hamburgh and Elberfeld, were about 200 miles distant. Here again it may be presumed that the separation was too great, since, out of a great number observed, only five shooting stars could be actually iden

H 2

tified.

6

tified. But this paucity of positive results is familiar to practical astronomy; and Benzenburg consoled himself in quoting the phrase of Lalande: Il n'y a que les astronomes qui sachent par combien d'observations manquées on en achète une seule qui réussit.'

During the remainder of the period we have named, similar observations were repeated by the same and many other observers, in various parts of Germany, with different lengths of base, and aided by formula which Olbers and Erman had respectively suggested. Such, however, was the difficulty of establishing identity, that in 1823, a year particularly devoted to this research, out of 1712 shooting stars actually observed, only thirty-seven could be conclusively regarded as the same seen at different stations. Nevertheless many valuable results were obtained, sufficient to indicate the general character of these meteors, and to associate them more closely with the fire-balls before described. Their height-varying, of course, in different shooting stars, and at the moments of appearance and disappearance of each-was found to range from 15 to 140 or 150 miles-(some statements much higher than these are made doubtful by the smallness of the parallax); their velocity to be that of planetary bodies, reaching frequently to thirty miles in the second. These conditions, together with the directions of the paths they describe in reference to the motion of the earth, suffice to assign their place as parts of the planetary system, however small or attenuated the aggregations of matter thus presented to us.

A far more striking evidence, however, to this effect speedily followed, from the discovery of a periodical character in some of those showers of meteors, which at certain times startle the spectator by their number and brilliancy. The earliest suggestion of this arose from an extraordinary apparition of such meteors in the northern part of the United States on the nights of the 12th and 13th of November, 1833; the description of which in much detail was given by Professor Olmsted, of Newhaven, and other observers. The asteroids composing this fiery shower graduated from the simple phosphorescent line of the shooting star to luminous globes of the moon's diameter-all of them conforming to one condition (the most important of the facts observed), that of issuing from the same point in the constellation Leo; and continuing to proceed from this point, though the rotation of the earth during the progress of the phenomena had greatly changed its apparent place in the heavens. The value of this observation was at once recognised. Sporadic shooting-stars are observed to traverse the sky in all directions. But these multitudinous meteors of a night, in their radiation from one point, showed a

common

common origin, and the approach of the earth in its orbit to some other revolving volume of matter, visible only through the changes made by this approximation.

Intelligence of this event, confirmed by other observers in different localities, awakened a new and keener interest in the subject. Reference was made to the same date in antecedent years, and several instances discovered in which about the 12th of November extraordinary falls of shooting stars had occurred ;— the most remarkable, that described by Humboldt and Bompland in 1799, which occurred to their observation at Cumana, but was seen very extensively over the earth. Earnest expectation also was directed towards the future. On the night of the 12th November, 1834, shooting-stars were very numerously seen by the same American observers, and proceeding from the same point in the heavens; but the light of the moon rendered the results partial and uncertain. In succeeding years the phenomena were more vaguely seen, or altogether absent; except in 1837 and 1838, when they recurred, but more partially as to localities. In the former year, for instance, they formed a striking spectacle in some parts of England, while scarcely visible in Germany. Though M. Saigey imputes much exaggeration in numbers to the Transatlantic reports, they have been admitted by the very highest men of science-Arago, Biot, Herschel, Humboldt, Encke, &c.—as fully proving the periodical return of certain groups of asteroids, or of the matter generating them. To Encke we owe the calculation that the point in Leo, from which these November meteorites issued, is precisely the direction in which the earth was moving in its orbit at this particular time-a fact, the value of which in relation to their theory will readily be understood.

But the eager attention now given to the subject speedily evoked other results. It was found, as well from prior record as from present observation, that November was not the sole period of recurrence of such phenomena. Tradition, both in England and elsewhere, pointed out the 10th of August, St. Lawrence'sday, as frequently marked by these fiery showers. In some parts of Germany the belief ran that St. Lawrence wept tears of fire on the night of his fête. An old monkish calendar, found at Cambridge, reciting the natural events which belong to different days of the year, designates this day as one of meteors (meteorodes). We find a curious notice by Sir W. Hamilton of such a shower, as he witnessed it at Naples on August 10, 1799. In 1839 these August asteroids were very remarkable; and it has been distinctly ascertained that they proceeded from a point in the heavens between Perseus and Taurus, in direction towards which point the earth traverses a tangent to her orbit at the time-a

very striking concurrence with the facts just stated respecting the November phenomena. Further research has indicated other times of the year-in April, July, and December-marked by like periodical appearances; but the evidence is less distinct, and does not go further than to justify the demand for future and multiplied observations.

The admission of these wonderful facts created instant inquiry into their cause. No theory was seemingly tenable which did not recognise in some form a revolution round the Sun of the matter composing or evolving these asteroids. Professor Olmsted, and other American naturalists, fresh from the spectacle that had been before their eyes, took up the question before it had been treated in Europe; and the former, collecting all the facts, deduced from them the existence of a nebulous cloud or mass of meteoric stars, approaching the earth at particular periods of its revolution, under conditions as to time, direction, and physical changes from proximity, which we have not space to detail. His speculation that this meteoric cloud might be part of the solar nebula known under the name of the Zodiacal Light, was taken up and enlarged upon by Biot, in a memoir read before the Académie des Sciences in 1836. The first exact observer of the zodiacal light, Cassini, had long before inferred that it consists of divided or diffused planetary matter. It is shown by Biot that on the 13th of November the earth is in such relative position that it must necessarily act by attraction or contact upon the material particles of which this nebula is composed, producing phenomena which we may reasonably consider to be represented by these meteoric showers. He carries the same theory to the explanation of the sporadic shooting-stars of ordinary nights, by supposing that the habitual passage of Mercury and Venus across the more central regions of this nebula must have dispersed innumerable particles in orbits very little inclined to the ecliptic, and so variously directed that the earth may encounter, attract, and render them luminous in every part of its revolution.

Objections have been raised to this theory, and it remains without any fresh confirmation. But under any form that can be given to the question before us, it seems needful, as we have said, to assume for its solution the existence of matter, revolving either in zones or in separate masses and groups, containing the material of these asteroids. The hypothesis of matter thus arranged, having periods of revolution more or less regular, and intersecting the orbit of the earth in certain points at certain times, has been adopted by Arago, Herschel, and other eminent astronomers; and the conception of a zone or zones of such matter is admitted as best fulfilling on the whole the conditions of the

problem.