Page images
PDF
EPUB

but spoke not at all. Well done, a nameless, voiceless boy! amid windbags and unpractabilities, thy golden silence was sublime. For he who once has thought aright, need never speak again. He has done enough for fame.

Meteors.

W

E learnt last November, or we ought to have learnt, what

was the orbit of the meteors and how it was determined : but most of us at least were unable to gain any clear idea of the appearance and nature of meteors from any observation of the shower of that month, owing to persistent cloud. As I happen to have heard a lecture on the subject, delivered by Alex. Herschel, F.R.A.S., who has devoted himself much to this study, perhaps I may be permitted to give a very brief, not to say meagre sketch of the external phenomena of meteors.

First, as to the ancient records of them. The Chinese kept catalogues of them, probably as far back as the times of David and Solomon; and Homer seems to represent them in a personified form in his myths of the expulsion of Vulcan from heaven. The famous temple of the Ephesian Artemis contained in its innermost sanctuary an image of the goddess which men said fell down from heaven, which image was of no celestial beauty, but a rough black stone, two feet high, whose upper part was cut into a rude semblance of the human face,-in fact, an ordinary meteorite roughly fashioned by

The ancile of Numa and the Palladium of Troy, were probably of the same origin.

Considering that it is probable that about 7,500,000 shooting stars pass through the earth's atmosphere every day, it seems strange at first sight that the earth should be anything more than a desert and a boiling sea, ploughed continually by falling iron. But we must remember that most of these shooting stars are no bigger than a racquet ball-many much smaller; and at 80 or 90 miles from the earth they begin to feel the obstruction of the earth's atmosphere, and are soon subjected to a pressure of about 1000 tons on the sq. inch, which effectually annihilates them in a second or two. Moreover, of those that do fall, probably not more than

vage art.

two or three per cent. are noticed, many falling in uninhabited places, many more in the sea. Of the actual fall of few have we authentic records from eye witnesses. One that fell at mid-day, in Austria, in 1751, was seen by many at the time, and is preserved among the crown jewels. This was a mass of iron. of two cwt. Another fell into the cravat of a London waiter : this was of a somewhat smaller sort. But most men feared the charge of credulity too much to give in their adhesion to the belief that these were no products of the earth, though some thought they were the scoriae of volcanoes in the moon.

As late as 1768, Lavoisier, the great French chemist, was commissioned to report on three which were found that year, and his verdict was that the lightning had descended upon-a vein of iron ore, and had torn off and melted pieces of it. But this explanation did not satisfy Biot and Chladni, and careful examination was made of all the phenomena accompanying their fall.

Halley, the astronomer, investigated thoroughly the circum stances which attended the fall of a great fireball which passed over Cornwall, in 1719, A.D. It was as bright as the sun, and the concussion which accompanied it, though occurring at the distance of 60 miles from the earth, was such as to shake looking glasses from their frames. Biot went thoroughly into the details of a stone shower, and found stones scattered over an area of 50 sq. miles. Another observer had the opportunity of handling a newly fallen aerolite. He touched the outside with his right hand, and was severely burnt by its heat. The aerolite was broken, and he touched the inside with his left : again, as the story goes, he was burnt, but this time not by heat but by cold.

These were strange facts, and hard to be accounted for by any lightning hypothesis like that of Lavoisier. Halley, it seems, was a classicist, and turned to his Aristotle for an explanation. He found Aristotle had considered the matter, and had settled that the smaller shooting stars were long cylinders of gas which spontaneously ignited and burnt from end to end. The thousand difficulties arising from this hypothesis, as to how the gas could be maintained in vivid combustion in the rare air at great heights, how it was ignited, &c., Aristotle apparently had not settled, or perhaps had not considered.

In the years 1758 and 1783, were observed two of the largest meteors which appeared in the century: their calculated height in the atmosphere was about 50 miles, and they were accompanied, as was that described by Hally, by loud explosions. The discovery about this time of Atmospheric Electricity, gave rise to the idea that meteors might be electrical phenomena occurring in an electrical stratum which was supposed to exist above the stratum of air. This hypothesis, however, becomes untenable when it is shewn how feeble and how diffuse the electric spark becomes in very rare gases. All meteors, especially fireballs, which are the brightest class, exhibit a definite outline and a brightness which are quite irreconcileable with this hypothesis. Chladni, of Wittemberg, was the first who saw deeper into the matter. He conceived that there existed a class of bodies in all parts of the solar system, which the earth from time to time encountered, as they moved round the sun with a velocity as great as its own. When air is confined by a piston in a tube, and the piston carrying a piece of tinder or other light substance at the end, is forced suddenly into the tube, the heat developed by the compression of the air is so great as to ignite the tinder. The passage of a celestial body through the atmosphere must be intensely rapid, so that before the air can escape from the front of such a projectile it must necessarily undergo a violent compression of the kind exemplified in this match syringe, and the heat duveloped at its surface must doubtless far surpass what can be produced by mechanical means; a speed of thirty miles a second, which is about the average rate of meteors, would produce on the meteoric body a heat sufficient to fuse, and probably to volatilize, the most refractory substances. Not only the thin glazed surface with which the aerolites are invariably covered but also the appearance of fireballs, or shooting stars, can be satisfactorily explained on this hypothesis.

The progress of knowledge regarding shooting stars may be almost identified with the history of the November star shower. In 902, Oct. 13, the year of stars,' we have the first notice of a great autumnal shower. The shower has grown later since then by reason of the retarding influence of those heavy planets, Jupiter, Saturn and Uranus. Several notices are extant of October or November showers in the intervening centuries, but no one seems to have imagined that they were periodic. In 1799 Humboldt was in South America and obtained a clear view of a grand shower. He questioned the natives and he found that they remembered a similar shower in 1766. However, still he did not conceive of their periodicity. Their recurrence, on Nov. 13, 1833, suggested it, and it has been confirmed by the shower of 1866. The shower was visible in its grandest magnificence in North America, and negroes of South Carolina shrieked and prayed all night, supposing that it was the end of the world. The next recurrence was predicted for Nov. 14, 1867, and the event justified the prediction, notices of the time of its arrival were sent all over the globe, and observers were ready. It was very brief, lasting little more than three hours, but very thick, 8000 being counted during that time, and many being left out from the rapidity of their succession to each other. Everyone was on the look-out for them, and many wrote accounts of them to their papers, among whom was the Damascene, Solyman Effendi Soolah. who says—'In this past night the stars began the war from the east to the west and from the southern to the northern side. They dashed at the pace of fiery steeds and ghouls, so that you could not distinguish the Pleiades from the Hyades, from the passing of the meteors across them and the intensity of the brightness. But you now thought that the two stars in Leo's nose had been dispersed, and the two fishes were eclipsed and immersed, and the spearman of Areturus had forgotten his spear and was thinking only of his own safety, and the Adhal was complaining to the bright daughters of the Bear about the extent of his wound, and the lofty Pole had fallen into the claws of the Eagle, and the Hedrah was prostrate, and the face of night like a leopard's skin; and to sum up all, the heavens were like a sphere of fire, or a gleaming of sparks, excepting that the fire and sparks were harmless, not touching the earth, or injuring our safety; as if night's starry horsemen, who continued till morning beating each other in single combat, gave us protection and peace. This I write for his Excellency our Prince, the Sultan Abdul Azizkhan. May God perpetuate his government to the end of the world's revolution.'

The observations made during this shower extended the science of meteors greatly. By a new consent of master minds, M. Le Verrier and Professor Adams, at the end of elaborate calculations, both agreed in determining that the true orbit of the meteoric stream is a long ellipse, extending from the Earth's orbit, at its least, to that of Uranus at its greatest distance from the sun.

The periodic time of the meteors is 33) years, and they revolve round the sun in the opposite direction to that of the earth's course.

A most curious incident connected with these discoveries is, that a comet has been found moving in exactly the same orbit as these November meteors, and taking exactly the same time to complete its course round the sun; moreover, comets have been found which move in exactly the same track as other meteor showers, so that some physical connection seems little less than certain. It is not impossible that the meteoric particles are portions of the comet's tail, shreds of a dismembered mist, torn by the sun's disturbing action from the nucleus of the comet, and left upon its path like embers or smoke-flakes in the track of its retreating flame.

The Cheltonian Fund.

remarks upon

In your last number there appeared some few suggestions with reference to the formation of a 'Society, or Club, to bring Cheltenham Collegians together.' With your permission, I will offer some

those suggestions. It seems to me that the want so much felt is not that of a 'Club, to bring Cheltenham Collegians together,' but rather that of a Fund, presided over by a Committee, who shall be entrusted to expend the money in whatever way may be considered best for the general interest of the College.' Let this Fund be once fairly started, the meeting of old Collegians will necessarily follow; but, on the other hand, will the Fund necessarily follow in the train of the Club? I fear not. On the subject of Voluntary Contributions, I have a few words to say. All will allow that in raising the Fund, our great object to aim at is—how can we best aid the interests of our school? In other words— how can we get the largest sum of money? By Voluntary Subscription or by Annual Subscription? Are there a sufficient number of old Cheltonians, who possess both the will and the means (for either one without the other would not much benefit our fund), to give any material assistance to the College? Are there not many, even hundreds, who would persuade themselves that they could not afford a Voluntary Donation, although they would willingly give their ios. per annum? Would not many, not liking to give a small Donation, avail themselves of the loop-hole thus offered, and not give at all? I fear there are. It would have a tendency to place those who have the will but not the means, in an invidious position, which could not work well. Such distinctions had far better be avoided. But let us now apply ourselves to the present. Whether we have Voluntary Subscriptions or Annual Subscriptions, our present duty is to start a Fund, by collecting the Entrance Fees; we shall then have some ground to stand upon.

I will now make a few remarks in favour of Annual Subscriptions. It would not preclude those who wished from giving more liberally. It would embrace a great many members who would escape under the other system. It would be more reliable, so that the Committee could form some fair estimate of what its year's income would be; whereas the Voluntary system would be for ever varying-lastly, it would be always increasing.

These are the advantages I claim for the Annual Subscription system, besides the disadvantages of the Voluntary plan above alluded to.

« EelmineJätka »