HALLIDI

OF THE

UNIVERSITY

CALIFORNIA

UNIV. OF

Astronomy,

AS IT IS KNOWN AT THE PRESENT DAY.

ON THE UTILITY OF ASTRONOMY.

ASTRONOMY is one of the most ancient and one of the most pleasing branches of knowledge which has ever engaged the human mind. The grandeur and sublimity of the objects it presents elevate and improve the mind, banish low and frivolous passions, and become a source of never-ceasing pleasure.

No species of knowledge that is attained by the light of nature, gives higher or juster notions of the Supreme Being; no science affords stronger arguments by which his existence is demonstrated; and none gives more convincing proofs of HIS power and wisdom; for, as David says, "the heavens declare the glory of God, and the firmament sheweth his handy work."

Cicero, who was guided only by the light of reason, appears to have had the same sentiments; for "nothing," says he, " is more evident, nothing is plainer, when we look up to the heavens, and contemplate the celestial bodies, than that there is a Deity of most excellent wisdom who governs them.'

For the certainty and evidence of its demonstrations, Astronomy is not inferior to Geometry: the motions of the heavenly bodies being now as certainly known, and their causes as strictly demonstrated, as any proposition in pure Mathematics.

The smallest stars we can see, though at an immeasurable distance from us, have their latitude and longitude as exactly determined as any place on the earth; and the eclipses of the sun and moon, the conjunctions, oppositions, and phases of the planets, are calculated with the greatest precision.

"There is no science," says Dr. Keil, "in which there remains fewer difficulties to be explained, objections to be answered, or scruples to be removed, than in Astronomy, and no science has attained so high a degree of perfection as it has; for no philosopher has ever yet discovered the figure of the small particles of matter, or the texture, intervals, form, and composition, of the parts of the most common plant."

Nor has any Physician yet discovered the reason of the virtues and operations by which his medicines affect the human body. And No. 1.

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in all ANIMAL and VEGETABLE bodies, the fountain and first principle of LIFE and ACTION are unsearchable, and look like a mystery far beyond the reach of our understanding, and perhaps may for ever remain unknown to us.

But Astronomers (in their proper sphere) meet with no such difficulties, for it is no part of their business to contemplate the nature of the celestial bodies; but their motions, their magnitudes, and the various phenomena arising from their motions.

They not only determine what sort of motions the PLANETS have, how large orbits they describe, and how long they take to complete their revolutions, but they likewise show the crooked tracts in the immense regions of space which the wandering Comets describe, and give us the geometrical dimensions and properties of their orbits, and the laws they observe in describing them.

Astronomy has at all times been studied by the greatest philosophers and men of genius in every part of the world; and the most celebrated of the ancients speak of it with admiration. When Anaxagorus was asked for what end he was born, he answered, "To contemplate the Stars." If there is much enthusiasm in this reply, we at least see with what admiration a man of genius contemplated the sublime spectacle of the heavens.

Plato had also the highest regard for this science; for in his work, entitled "Epinomis, or the Philosopher," he says, "that no wise man would be ignorant of Astronomy."

This science not only contributes to the improvement of many other sciences, but it is also of admirable use in strengthening the mind, and arming the reason against the effects of ignorance and superstition.

Every one must allow that morals would be quite vague, and have but few attractions, if founded on ignorance or error. Ought it then to be accounted of no value, to have the advantage of being preserved from the fatal effects arising from this cause?

Can we look without the emotions of compassion and pity on the stupidity of those, who believed that by making a great noise during the time the Moon was eclipsed, that it gave relief to her sufferings, and freed her from the disease with which she was supposed to be afflicted, and which they believed to be produced by enchantment?

Besides these errors, which degraded the human mind, we find in history many passages which show the FATAL EFFECTS arising from the ignorance of this science.

Nicias, the Athenian general, had resolved to quit Sicily with his army; but an Eclipse of the Moon made him lose the favourable opportunity, which was the cause of the death of the general, and the ruin of his army. This disaster was so fatal to the Athenians, that the decay of their country immediately followed it.

Alexander the Great was so afraid of an Eclipse of the Moon before the battle of Arbella, that he ordered sacrifices to be offered to the moon and to the earth, as to divinities that caused the eclipse.

On the contrary, we have many examples of those who possessed a knowledge of Astronomy, turning that knowledge to the greatest advantage, both to themselves and to their country.

When Pericles commanded the Roman fleet, there happened an Eclipse of the Sun, which caused a general terror throughout the fleet; even the PILOT himself was afraid.

Pericles, however, knew the true cause of the phenomenon, and reasoned with the Pilot in a very familiar manner; he took the end of his mantle, and after covering the eyes of the Pilot with it, said to him, "Do you believe that what I now do is a sign of misfortune ?" "No," said the Pilot. "This is an Eclipse to You," said Pericles," and it differs nothing from that which has just happened, except in this, that the Moon being larger than my MANTLE, hides the Sun from a greater number of persons."

Agathocles, king of Syracuse, while engaged in a war in Africa, found terror spreading through his army at the sight of a Solar Eclipse; he immediately presented himself to his soldiers, and explained the cause of the phenomenon, which had the effect of dispelling their fears, and restoring order.

Many other examples of the application of astronomical knowledge may be brought from history; but those already mentioned may serve to show the usefulness of Astronomy, even in affairs apparently nowise connected with it.

The story of Columbus and the natives of Jamaica, is too well known to require to be noticed here.

The knowledge of Astronomy has also been of great advantage in exposing the absurdities of Astrology, and freeing men's minds from that species of deception to which they were so long the dupes. In the year 1686, all the Astronomers in Europe agreed in announcing to the world a conjunction of all the Planets then known, which they said would be accompanied with such dreadful effects, that there would be great danger of a general overthrow, and every person expected to see the end of the world. That year, however, passed as others had done before it; but a hundred other false predictions were not sufficient to free the ignorant and credulous from the prepossessions and prejudices of their infancy. It was neces sary that a spirit of philosophy and research should spread among men; that the extent and limits of NATURE should be unfolded to them; and accustomed no more to fear without examination, and without proof; yet we still see, from time to time, the credulity of the public, in listening to the reveries of ignorance and superstition. So late as the year 1736, when there happened a very extraordinary HEAT, and furious wind, on the 20th October, it was published in all the Gazettes that the Sun had returned, or gone back to the tropic of Cancer. This was so generally believed, that it became necessary for the learned to take the trouble of undeceiving the public. About the end of the year 1768 too, every person believed the Planet Saturn lost; and it was even published in the most sensible periodical publications, and talked of in the most cultivated companies.

Comets were, above all, one of the greatest objects of terror; but a knowledge of Astronomy has shown these fears to be groundless, and has even dispelled them from the minds of the most ignorant.

But it is not only in this way that Astronomy has rendered itself useful it has been serviceable to mankind in many different ways. It is well known that Geography and Navigation are so intimately connected with Astronomy, that they cannot be separated, and that all the improvements and discoveries in these branches of knowledge are entirely owing to the science of Astronomy.

The observation of the altitude of the Pole Star, first taught men that the Earth was round; and Eclipses of the MOON first served to make known the Longitude of places. "We should not know," said Hypparchus, "whether Alexandria be to the North or South of Babylon, without the observation of Climates; and we cannot know whether a country be East or West of another, without the observation of Eclipses."

We find also by the Alcoran, that travellers in crossing the desert of Arabia took certain stars for their guides; for it is there said, that "God has given you the stars to serve you as guides, whether you be upon the land or the water."

The discovery of Jupiter's Satellites has given greater perfection to our geographical and marine charts, than could have been done for a thousand years by voyages and travels; and when their theory shall be rendered still more complete by multiplied observations, the method of finding the longitude will be both more easy and more accurate.

The improvements which have been made in geography since accurate observations began to be made in Astronomy, will be best understood by mentioning an example or two.

The length of the Mediterranean Sea was unknown till the beginning of the seventeenth century, but is now as well known as the length of Great Britain.

The difference of Longitude between Cairo, and Toledo in Spain, is stated, in the geography of Gemma Trisius, (published 1530,) to be 53° instead of 34° 36'; and other distances are exaggerated in the same manner.

Till the year 1769, there were three or four degrees uncertain on the length of the CASPIAN and BLACK Seas; and before the same year there was an error of half a degree in the Longitude of Gibraltar.

America was unknown till the year 1502; and its discovery is solely to be attributed to the knowledge of Astronomy possessed by Columbus.

It appears he had an intimate acquaintance with the doctrine of the Sphere, which gave him that confidence which prompted him to direct his course to the westward, certain of either coming on the east continent of Asia, or of discovering a new one. If any thing yet remains for the improvement and security of navigation, it is an easier and more expiditious method of finding the longitude at sea.

There is at present a method of performing this with great accuracy, by means of measuring the distance between the sun and moon, or the moon and a star; and if seainen knew a little of Astronomy, they never could be deceived above ten leagues, whilst they are sometimes more than 200 uncertain, on ordinary voyages, such as going to America and the West Indies.

The uncertainty that Lord Anson was in, respecting the situation of the island of Juan Fernandez, made him keep the sea much longer than would have been necessary, had not this been the case, which might have saved the lives of seventy or eighty of his men. But accidents even more fatal than this have been occasioned by errors of a similar kind.

The advantages of navigation to the success of a nation prove in a very convincing manner the usefulness of Astronomy.

The trade and prosperity of Great Britain, as well as her success at sea in war, shows that the Navy alone can decide the fate of Empires and give to a nation both wealth and power; for, as M. le Meire says, "The TRIDENT of Neptune is the Sceptre of the world."

Agriculture formerly borrowed from Astronomy most of its rules and indications; for Job, Hesiod, Verron, Eudoxus, Aratus, Ovid, and Pliny, furnish us with proofs of this; the HELIACAL rising or setting of the Pleiades, of Arcturus, Orion, and Sirius, gave to the Greeks and Egyptians the signal for different kinds of work.

For example: the rising of Sirius announced to the Greeks the time of harvest, and to the Egyptians the overflowing of the Nile.

Ancient Chronology receives, from the knowledge and calculation of Eclipses, the most certain points, or epochs, that it is possible for us to have. The Chronology of the Chinese is all founded on Eclipses of the Sun and Moon; and if there had always been Astronomers in the world, there would be no uncertainty in the date of any remarkable event mentioned in history.

It is by an Eclipse of the Moon that an error has been discovered in the date or commencement of the Christian era, or birth of Jesus Christ. We know that Herod was king of Judea; and we are bab informed by Josephus, that there was an Eclipse of the Moon immediately before the death of Herod. Now we find that this Eclipse happened in the night of the 12th or 13th of March, four years before the commencement of the vulgar era; therefore that era ought to be put back three years at least.

It is also by knowing that an Eclipse of the Sun can only happen at the time of NEW MOON, and that he can only be totally eclipsed for a few minutes (74), that Christians are convinced that the darkness which took place at the crucifixion of Jesus Christ was supernatural; for this event took place at the time of the Jews' PASSOVER, which was kept at the time of FULL MOON.

It is likewise by means of Eclipses of the Sun, that Castor fixed the termination of the war between the Lydians and Medes to the

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