THE prediction of eclipses has, from the earliest ages, excited the admiration of mankind, and been one grand instrument by which their allegiance (so to speak) to natural science, and their respect for its professors, has been maintained; and though strangely abused in unenlightened ages by the supernatural pretensions of astrologers, the credence given even to their absurdities shows the force of this kind of evidence on men's minds. The predictions of astronomers are, however, now far too familiar to endanger the just equipoise of our judgment, since even the return of comets, true to their paths and exact to the hour of their appointment, has ceased to amaze, though it must ever delight all who have souls capable of being penetrated by such beautiful instances of accordance between theory and facts. But the age of mere wonder in such things is past, and men prefer being guided and enlightened, to being astonished and dazzled. Eclipses, comets, and the like, afford but rare and transient displays of the powers of calculation, and of the certainty of the principles on which it is grounded. A page of "lunar distances" from the Nautical Almanac is worth all the eclipses that have ever happened, for inspiring this necessary confidence in the conclusions of science. That a man, by merely measuring the moon's apparent distance from a star with a little portable instrument held in his hand, and applied to his eye even with so unstable a footing as the deck of a ship, shall say positively within five miles, where he is, on a boundless ocean, cannot but appear to persons ignorant of physical astronomy, an approach to the miraculous. Yet the alternatives of life and death, wealth and ruin, are daily and hourly staked with perfect confidence on these marvellous computations, which might almost seem to have been devised on purpose to show how closely the extremes of speculative refinement and practical utility can be brought to approximate. We have before us an anecdote communicated to us by a naval officer, distinguished for the extent and variety of his attainments, which shows how impressive such results may become in practice. He sailed from San Blas, on the west coast of Mexico, and after a voyage of eight thousand miles, occupying eighty-nine days, arrived off Rio de Janeiro, having in this interval passed through the Pacific Ocean, rounded Cape Horn, and crossed the South Atlantic, without making any land, or even seeing a single sail, with the exception of an American whaler off Cape Horn. Arrived within a week's sail of Rio, he set seriously about determining, by lunar observations, the precise line of the ship's course, and its situation in it at a determinate moment; and having ascertained this within from five to ten miles, ran the rest of the way by those more ready and compendious methods known to navigators, which can be safely employed for short trips between one known point and another, but which cannot be trusted in long voyages, where the moon is the only sure guide. The rest of the tale we are enabled, by his kindness, to state in his own words :-"We steered towards Rio de Janeiro for some days after taking the lunars above described, and having arrived within fifteen or twenty miles of the coast, I hove-to at four in the morning till the day should break, and then bore up; for although it was very hazy, we could see before us a couple of miles or so. About eight o'clock it became so foggy that I did not like to stand in farther, and was just bringing the ship to the wind again before sending the people to breakfast, when it suddenly cleared off, and I had the satisfaction of seeing the great Sugar-loaf Rock, which stands on one side of the harbour's mouth, so nearly right a-head, that we had not to alter our course above a point in order to hit the entrance of Rio. This was the first land we had seen for three months, after crossing so many seas, and being set backwards and forwards by innumerable currents and foul winds." The effect on all on board might well be conceived to have been electric; and it is needless to remark how essentially the authority of a commanding officer over his crew may be strengthened by the occurrence of such incidents, indicative of a degree of knowledge and consequent power beyond their reach.-HERSCHEL'S Natural Philosophy.' THERE can have been no period in the history of mankind in which they did not behold, with a desire to comprehend them, the changes which are daily taking place in the face of the heavens above them; and there can have been none in which they did not perceive these changes to sympathize with others in the surface of the earth around them. He who looks out upon the heavens beholds a canopy spread forth like the half of a great sphere, of which he appears to occupy the centre. In the daytime, when it is of the colour of the azure-the hue of light in which his perception of its existence is most pleasant to him-the sun daily takes his course, in a zone, across this fair canopy, “like a giant that renews his strength." As night approaches, the curtain of the heavens gradually loses its transparent blueness, becomes opaque, darkens, and at length it is black as sackcloth of hair; then come the millions of the stars which are strewed like gems upon its surface; and in her season the moon walks forth in her brightness, and holds sway amid the dreary watches of the night. These daily changes in the heavens have but little apparent relation to the changes of vegetable life, but over the whole of the animated creation their power is manifest. The song of the birds becomes mute at nightfall and again wakes only to welcome the returning sun. The beast lies down in the forest, the reptile crawls to his lair, and man himself sinks under the mysterious influence of the changing heavens; and returning to a state, the image of that state of oblivion out of which his birth first brought him, he stretches himself out to sleep. Such is the experience of a day. That of a year brings us still further knowledge of the wonderful sympathy between the changes in the heavens above him, and those in the things around him. He sees the sun, not daily to describe the same path in the heavens, but at one time to travel obliquely across them in a higher, and at another time in a lower zone, so as at one time to have a longer course to run, and at another a shorter; and thus at one time to give him a longer and at another a shorter day. This change in the elevation and consequent length of the sun's oblique path in the heavens he soon perceives to be coupled with a change in his own perceptions of the intensity of heat and cold. When the sun's path is lowest or most oblique, he is colder than when it is highest; and not only do his own feelings sympathize with this change, but all nature around him. The hand that covered the beast of the forest with a coat of fur, in the winter thickens its garment. The bird whose path is free in the heavens, then, guided by a spark of that intelligence which called it into being, becomes conscious of the existence of a warmer sky in some remote unseen region of the earth, and seeks it. The green herb withers, the blossom dies, the leaf becomes sapless and falls to the ground. Is it possible that he who beholds all these changes around him, and who is thus deeply interested in them-who cannot but see that they are all bound together as by a chain, and made to sympathize with one another-should not seek to trace out still more of the mystery of their union, to know more of its nature and laws, and to unravel its cause? Man is necessarily, and from the very mode and nature of his existence a speculative being. And of all the subjects of speculation, the changes in the heavens are probably those which first arrested his attention. How earnestly, for instance, must the master-spirits of those days, when the secret of the universe was unknown, have wished and have laboured to account for the phenomena which we now so readily explain by means of our knowledge of the form of the earth: how must the mysterious alternation of day and night, and the march of the seasons, have distracted them, wearied their imaginations, and perplexed their reasonings? The mighty changes in the heavens, controlling, as they do, all the phenomena of animal and vegetable life, necessarily couple themselves in the mind with the direct agency of the supernatural world; and thus it was that the astronomy of the ancients became incorporated with their mythology. And thus, "the history of the development of the religious principle among them was little other than a history of the wanderings and uncertainties of the human understanding, which, placed in a world it could not comprehend, sought nevertheless with unwearied solicitude to develop the secret of it; which, a spectator of the mysterious and visible prodigy of the universe, imagined causes for it, supposed objects, and raised up systems; which, finding one defective, destroyed it to raise another not less faulty on its ruins; which abhorred the errors that it renounced, misunderstood those which it embraced; repulsed the very truth for which it sought; conjured up chimeras of invisible agents; and, dreaming on, without discretion and without happiness, was at length utterly bewildered in a labyrinth of illusions." How great is the contrast! Since the age in which the heathen mythology had its origin, the religion of mankind has fixed itself upon the sure foundation of a revelation from God, and the human understanding has acquired for itself the master-secret of the universe. The wanderings of the stars on the firmament of the heavens are at length understood. We find in what appeared to our ancestors the capricious motions of powerful but isolated beings, evidences of one impulse, one will, one design, one Almighty power, originating, sustaining and controlling the whole. These beings then, to whom, calling them their gods, it was natural that they should attribute a separate, independent, and capricious existence, subject to the indecision, the error, and the feebleness of humanity, appear to us but as the creatures of one sovereign intelligence, bound down in as passive obedience to that intelligence as the stone that falls from the hand, or the apple that falls from the tree, with no other thought, or will, or power, than that of any particle of dust blown about by the summer's wind. Thus the whole of the sublime and gorgeous pageantry of the heathen mythology vanishes like the baseless fabric of a dream. We know that this magnificent phantom retained its shadowy control over the intellect of man in an age of great literary refinement, of profound knowledge in the philosophy of morals, and of high civilization; and had no revelation interposed, there could be nothing found in the mere literature, ethics, and civilization of our day, as distinguished from the literature, ethics, and civilization of theirs, to overthrow it; thus we might still, in respect to these, be what we are, and yet the worshippers of a host of gods: but combine with these the science of our times, and the supposition becomes impossible; a single ray penetrating the mystery of the universe is sufficient to dispel the illusion of polytheism. How prodigious has been the progress which the universal mind of man has since made, how wonderful the vantage ground on which we stand, when we look forth upon nature. In comparison with that time of its infancy, the human intellect now walks to and fro in creation, as with the strength of a giant, the growth of whose stature has been through ages, and who is yet removed by an interval of ages from the noontide of its vigour.MOSELEY'S Lectures on Astronomy.' 6 1. The earliest accounts we have of astronomy are those of Babylon, about 2234 B.C. The science was much advanced in Chaldæa under Nabonassar; it was known to the Chinese 1160 B.C.; some say many centuries before. Lunar eclipses were observed at Babylon, with exceeding accuracy, 720 B.C. The sphe rical form of the earth, and the true cause of lunar eclipses, were taught by Thales 620 B.C.-See HAYDN'S Dictionary of Dates.' ADAM AND EVE CONVERSING IN PARADISE |