he Sector was found, in both cases, to be deflected from the perpendicular towards the mountain; and, from calculations founded on the quantity of this deflection, the mean density of the earth was ascer ained. It was likewise by means of celestial observations that the length of a degree of the meridian was measured, and the circumference of the globe, with all its other dimensions accurately ascertained; for, to ascertain the number of degrees between any two parallels on the Earth's surface, observations must be taken, with proper instruments, of the sun or of the stars, at different sta tions; and the accurate measurement of the terrestrial distance between any two stations or parallels, partly depends on astronomical observations combined with the principles and operations of Trigonometry. So that without the aids of this science. the figure and density, the circumference and diameter of our terrestrial habitation, and the relative position of places on its surface, could never have been ascertained.

Astronomy is likewise of great utility to the art of

NAVIGATION;

without a certain knowledge of which the mariner could never have traced his course through pathless oceans to remote regionsthe globe would never have been circumnavigated, nor an intercourse opened between the inhabitants of distant lands. It is of essential importance to the navigator, not only to know the situation of the port to which he is bound, but also to ascertain with precision, on what particular portion of the terraqueous globe he is at any time placed-what course he is pursuing-how far he has travelled from the port at which he embarked-what dangerous rocks or shoals lie near the line of his course-and in what direction he must steer, in order to arrive, by the speediest and the safest course, to his destined haven. It is only, or chiefly, by astronomical observations that such particulars can be determined. By accurately observing the distance between the moon and certain stars, at a particular time, he can calculate his distance East or West from a given meridian; and, by taking the meridian altitude of the sun or of a star, he can learn his distance from the Equator or from the poles of the world. In such observations, a knowledge of the conStellations, of the polestar, and of the general positions of all the stars of the first and second magnitude, is of particular importance; and, therefore, a navigator who is unacquainted with the science of the heavens, ought never to be appointed to conduct a ship through the Indian, the Atlantic, or the Pacific oceans, or through any portions of the sea which is not within sight of land. By the observations founded on astronomical science, which have been made in different regions, by mariners and travellers of various descriptions, the latitudes and longitudes of the principal places on the globe, and their various bearings and relations have been determined, so that we can now take a view of the world we inhabit in all its multifarious aspects, and direct our course to any quarter of it, either for business, for pleasure, or for the promotion of philanthropic objects. Thus, Astronomy has likewise become of immense utility to Trade and Commerce, in opening up new emporiums for vur

manufactures, in augmenting and multiplying the sources of wealth, in promoting an intercourse between the most distant nations, and enabling us to procure, for our accommodation or luxury, the productions of every climate. If science has now explored almost every region; if Politics and Philosophy have opened a communication between the remotest inhabitants of the globe; if alliances have been formed between the most distant tribes of mankind; if Traffic has explored the multifarious productions of the earth and seas, and transported them from one country to another, and, if heathen lands and barbarous tribes have been "visited with the Day-spring from on high, and the knowledge of salvation,”-it is owing to the aids derived from the science of the stars, without which the continents, the islands, and the different aspects of our globe would never have been explored by those who were separated from them by intervening oceans.

This science has been no less useful to

AGRICULTURE,

and to the cultivators of the earth. The successful cultivation of the soil depends on a knowledge of the course of the sun, the exact length of the seasons, and the periods of the year most proper for the operations of tillage and sowing. The ancients were directed in these operations, in the first instance, by observing the courses of the moon, and that twelve revolutions of this luminary corresponded nearly with one apparent revolution of the sun. But finding the coincidence not exact, and that the time of the seasons was changing-in order to know the precise bounds of the sun's annual course, and the number of days corresponding to his apparent yearly revolution, they were obliged to examine with care what stars were successively obscured in the evening by the sun, or overpowered by the splendour of his light, and what stars were beginning to emerge from his rays, and to re-appear before the dawn of the morning. By certain ingenious methods, and numerous and attentive observations, they traced out the principal stars that lay in the line of the sun's apparent course, gave them certain names by which they might be afterwards distinguished, and then divided the circle of the heavens in which the sun appears to move, first into quadrants, and afterwards into 12 equal parts, now called the signs of the Zodiac, which they distinguished by names corresponding to certain objects and operations connected with the different seasons of the year. Such were the means requisite to be used for ascertaining the length of the year, and the commencement of the different seasons, and for directing the labours of the husbandman; -and, were the knowledge of these things to be obliterated by any extensive moral or physical convulsion, mankind would again be under the necessity of having recourse to astronomical observations for determining the limits of the solar year, and the course of the seasons Although we find no difficulty, in the present day, and require no anxious observations, in determining the seasons, yet, before astronomical observations were made with some degree of accuracy, the ancient Greeks had to watch the rising of Arcturus the Pleiades and Orion, to mark their seasons, and to determine the

proper time for their agricultural labours. The rising of the star Sirius along with the sun, announced to the Egyptians the period when they might exnect the overflowing of the Nile, and, consequently, the time when they were to sow their grain, cut their canals and reservoirs, and prepare the way for their expected harvest. 'The science of

CHRONOLOGY,

likewise depends on celestial observations. The knowledge of an exact measure of time is of considerable importance in arranging and conducting the affairs of life, without which, society in its movements would soon run into confusion. For example, if we could not ascertain, within an hour or two, when an assembly or any concourse of human beings was to meet for an important purpose, all such purposes would soon be frustrated, and human improvement prevented. Our ideas of time or succession in duration, are derived from motion; and in order to its being divided into equal parts, the motions on which we fix as standards of time must be constant and uniform, or at least, that any slight deviation from uniformity shall be capable of being ascertained. But we have no uniform motion on earth by which the lapse of duration can be accurately measured. Neither the flight of birds, the motion of the clouds, the gentle breeze, the impetuous whirlwind, the smooth-flowing river, the roaring cataract, the falling rain, nor even the flux and reflux of the ocean, regular as they generally are, could afford any certain standard for the measure of time. It is, therefore, to the motion of the celestial orbs alone that we can look for a standard of duration that is certain and invariable, and not liable to the changes that take place in all terrestrial movements. Those magnificent globes which roll around us in the canopy of the sky-whether their motions be considered as real or only apparent, move with an order and regularity which is not found in any physical agents connected with our globe; and when from this quarter we have derived any one invariable measure of time, we can subdivide it into the minutest portions, to subserve all the purposes of civil life, and the improvements of science. Without the aids of astronomy, therefore, we should have had no accurate ideas of the lapse of time, and should have been obliged, like the rude savage of the desert, to compute our time by the falls of snow, the succession of rainy seasons, the melting of the ice, or the progress and decay of vegetation.

Celestial observations, in consequence of having ascertained a regular measure of time, have enabled us to fix chronological dates, and to determine the principal epochs of History. Many of those epochs were coincident with remarkable eclipses of the sun or moon, which the ancients regarded as prognostics of the loss of battles, the death of monarchs, and the fall of empires; and which are recorded in connexion with such events, where no dates are mentioned. The astronomer, therefore, knowing the invariable movements of the heavenly orbs, and calculating backwards through the past periods of time, can ascertain what remarkable eclipses must have been visible at any particular time and place, and consequently, can determine the precise date of contemporary events.

Ca1visius, for example, founds his Chronology on 144 eclipses o. the sun, and 127 of the moon, which he had calculated for the pur pose of determining epochas and settling dates. The grand conjunction of the planets Jupiter and Saturn, which occurs once in 800 years, in the same point of the zodiac, and which has happened only eight times since the Mosaic Creation, furnishes Chronology with incontestable proofs of the date of events, when such phenomena happen to be recorded. On such data, Sir Isaac Newton determined the period when Thales the philosopher flourished, particu larly from the famous eclipse which he predicted, and which happened just as the two armies under Algattes, king of Lydia, and Cyaxares the Mede were engaged; and which has been calculated to have happened in the 4th year of the 43d Olympiad, or in the year before Christ 603. On similar grounds Dr. Halley, a celebrated astronomer of the last century, determined the very day and hour of the landing of Julius Cesar in Britain, merely from the circumstances stated in the "Commentaries" of that illustrious general.

Astronomy has likewise lent its aid to the

PROPAGATION OF RELIGION,

and the conversion of the heathen world. For, without the light derived from this celestial science, oceans would never have been traversed, nor the continents and islands explored where benighted nations reside, and, consequently, no messengers of Peace could have been despatched to teach them "the knowledge of salvation, and to guide their steps in the way of peace." But, with the direction afforded by the heavenly orbs and the magnetic needle, thousands of Christian missionaries, along with millions of bibles, may now be transported to the most distant continents and islands of the ocean, to establish among them the "Law and Testimony" of the Mosi High-to illume the darkness and counteract the moral abomina tions and idolatries of the Pagan, world. If the predictions o. ancient prophets are to be fulfilled; if the glory of Jehovah is to cover the earth; if" the isles afar off," that have not yet heard of the fame of the Redeemer, nor seen his glory, are to be visited with the "Day-spring from on high," and enrolled among the citizens of Zion; if the world is to be regenerated, and Righteousness and Praise to spring forth before all nations-those grand events will be accomplished partly through the influence and direction of those celestial luminaries which are placed in the firmament to be for signs, and for seasons, and for days and years. The light reflected from the material heavens will lend its aid in illuminating the minds of the benighted tribes of mankind, till they be prepared for being transported into those celestial mansions where knowledge shall be perfected, and Sovereign power triumphant. It will be likewise from aid derived from the heavenly orbs that the desolate wastes of the globe in every region will be cultivated and replenished with inhabitants. For the Almighty" created not the earth in vain, bu formed it to be inhabited ;" and his purpose in this respect must ul imately be accomplished; and the process of pecpling and cultiva tion is now going forward in New Holland, Van Diemen's Lanu,

nere

Africa, the Western States of America, and other regions sterility and desolation have prevailed since the universal Deluge. But how could colonies of men be transported from civilized nations to those distant regions unless by the guidance of celestial luminaries, and by the aid of those arts which are founded on the observations of astronomy? So that this science exerts an extensive and beneficial influence over the most important affairs of mankind. In short, astronomy, by unfolding to us the causes of certain celestial phenomena, has tended to

DISSIPATÉ SUPERSTITIOUS NOTION'S and vain alarms. In former ages the approach of a blazing comet, or a total eclipse of the sun or moon, were regarded with universal consternation as prognostics of impending calamities, and as harbingers of Divine vengeance. And even in the present day, such notions prevail among most of those nations and tribes that are unacquainted with astronomical science. During the darkness occasioned by a solar eclipse, the lower orders of Turkey have been seen assembling in clusters in the streets, gazing wildly at the sun, running about in wild distraction, and firing volleys of muskets at the sun to frighten away the monster by which they supposed it was about to be devoured. The Moorish song of death, or the howl they make for the dead, has been heard, on such occasions, resounding from the mountains and the vales, while the women brought into the streets all the brass pans, and vessels, and iron atensils they could collect, and striking them with all their force, and uttering dreadful screams, occasioned a horrid noise that was heard for miles around. But astronomy has put to flight such terrific phantoms and groundless alarms, by unfolding to us the true causes of all such phenomena, and showing us that they happen in exact conformity with those invariable laws by which the Almighty conducts the machine of the universe-that eclipses are merely the effects of the shadow of one opaque globe falling upon another, and that comets are bodies which move in regular, but long elliptical arbits-which appear and disappear in stated periods of time, and are destined to subserve some grand and beneficent designs in the system to which they belong. So that we may now contemplate all such celestial phenomena, not only with composure and tranquillity, but with exultation and delight. In short, astronomy has undermined the absurd and fallacious notions by which the professors of Judicial Astrology have attempted to impose on the credulity of mankind, under pretence of disclosing the designs of Fate, and the events of futurity. It shows us, that the stars are placed at immeasurable distances from our terrestrial sphere that they can have no influence upon the earth, but what arises from the law of universal gravitation-that the great end for which they were created was to diffuse light, and to perform other important services in regions infinitely distinct from the sphere we occupy-that the planets are bodies of different sizes, and somewhat similar to the globe on which we live-that all their aspects and conjunctions are the result of physical laws which are regular and immutable—and that no data can be ascertained on which it can be proved that the