7,56 THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA LOS ANGELES UTLINES OF ASTRONOMY In Graham* s Standard Phonography CONTENTS The Figure of the Earth . The Motion of the Earth .'' The Moon .... V The Sun ..... . PARAGRAPH 3 4 5 6 The Planets ...... 7 Mercury i . . 9 Venus ..... . . . .10 The Earth ...... 1 1 Mars ........ 12 The Asteroids ...... 13 Jupiter ........ 14 Saturn ........ 15 Uranus ....... 16 Neptune ....... 17 Comets ....... 21 Day and Night ..... 23 The Figure of the Earth's Orbit Explanatory of the Variations of Day and Night ... 25 Phases or Changes of the Moon 26 Eclipses ....... 27 Eclipses of the Satellites . . .28 Tides ...... . . 29 PARAGRAPH Cause of the Tides . . . .31 The Zodiac 32 Divisions of the Celestial Sphere 3 3 Signs of the Zodiac ... 34 The Seasons 35 Causes of the Variations of Temperature . . . .36 General Divisions of Time . . 40 Sidereal Time 41 Solar Time 42 Cause of the Difference of Time in Different Parts of the World 43 The Calendar 44 Origin of the Names of the Month 45 Origin of the Names of the Days 46 The Sidereal System ... 47 The Fixed Stars 48 Binary Stars 49 The Constellations .... 50 The Milky Way . . . .51 The Nebulae 52 NEW YORK: ANDREW J. GRAHAiM & CO. THE WINTHROP PRESS, NEW YORK OUTLINES OF ASTRONOMY IN THE ADVANCED REPORTING STYLE OF GRAHAM'S STANDARD PHONOGRAPHY NEW YORK ANDREW J. GRAHAM & CO. 744 BROADWAY Copyright, 1899, by ANDREW J. GRAHAM & Co. OUTLINES OF ASTRONOMY. PREFACE. I I , x /^^ o C / vV-' -W--V-/ > N- ~ i. DESCRIPTIVE SKETCH. -v U /^ ^ I ,. > r -^/-X-' ->- .^_ ..c. , -.Ci^/Cp;.^ -X '- i -\ aci -yj J.-A - - - '--v^- - -^ x.""" i^. ^1 o,^ I ^ 449550 OUTLINES OF ASTRONOMY. ^~ V 3. ' ^= -\ I *" .-TV., ^~X> -~^ ^ D Vb / I ;! - 1 /--p "^yv^.t/ ^V- ^ v ^ i _./x_-l O ??--/ V^/ j> v.---~-^^-^ n c^:. [p| C xfS^A.t; ^ --^ __ _ / _/ 1 & xiy v^, ^ OUTLINES OF ASTRONOMY. O UT LINES OF A .9 TRONOM Y. \ J \> .rv*. _ v , _..x r c , I L ' S ^-/ ^ r 1 ^_- --=>- ' - - - vo (- -^V_^- - OUTLINES OF ASTRONOMY. --^ -- M c_ /.m -.-v - OUTLINES OF ASTRONOMY, ^- -\^; * : " "H "'-" r ->'^~--^-- ^v---^- ^^ \ / / /' V-V \x /7 jff*^/ , o-x r ^- v ^- 'V-^ - --y \- x . 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BY A MEMBER OF THE ENGLISH PHONETIC SOCIETY From The Standard-Phonographic Visitor. PREFACE. These " Outlines " have been composed more especially for the use of those whose early education has been neglected. Purely scientific technicalities have therefore been rejected, so far as was compatible with perspicuity and conciseness. Astronomy is one of the most useful and entertaining among the whole range of the strictly physical sciences, and is admir- ably adapted to expand the intellectual faculties ; and, indirectly, to exalt the moral affections. Under this conviction this little treatise has been prepared, and the earnest wish of the author is, that it may accomplish its intended purpose. I. DESCRIPTIVE SKETCH. 1. Astronomy is a term employed to designate the science of the material heavens. Being compounded of two Greek words, astron, a star, and nomos, a law, it signifies, literally, the law of the stars. While imparting a knowledge of those glittering orbs which spangle the heavens, it at the same time explains many of the most important physical phenomena connected with our earth. Some of these will be exhibited in the following pages.* 2. In nothing perhaps is the human mind more liable to de- ception, if its judgments be formed from appearances only, than in its estimation of those subjects which come properly within the sphere of astronomical science. To the uninformed observer, the earth upon which he dwells appears as a comparatively flat surface, or level plain, and also as a solid and immovable mass of matter. He looks upwards toward the magnificent ethereal expanse bespread around, and it appears as though the whole OUTLINES OF ASTRONOMY. 39 firmament, with its celestrial scenery, were continuously passing over his head, at no great distance from him. The starry hosts, too, seem to be no more than mere specks of luminous matter or small jets of light. Scientific discovery, however, dissipates the illusion and bears ample testimony that these first impressions are erroneous ; and it is the province of astronomy to rectify them and to present a more enlightened and philosophical con- ception of the universe. 3. The Figure of the Earth. We make this our starting point in a description of the heavens, because the earth being itself one of the heavenly bodies, and, in relation to ourselves, perhaps the most important one, a right knowledge of it will greatly facilitate a comprehension of the others. It has been dem- onstrated with mathematical certainty that the earth is not a plane surface but a globe/ and that so far from its being sta- tionary, it is incessantly moving. Its figure is not, however, completely spherical, but approaches more to the spheroidal form, or, as some have termed it, an oblate spheroid, that is, very much resembling the shape of an orange, having its ex- tremities flattened. Notwithstanding the unevenness and irreg- ularities of its surface, arising from alternate elevations and depressions, it is still spherical, for these, in comparison with its magnitude, induce no greater divisions from the globular form than the minute indentations upon the rind of an orange. For all practical purposes then the earth may be regarded as a globe. Rational arguments for its rotundity may be derived from the fact of several eminent nautical men, among whom was Captain Cook, having sailed completely round it. Traversing on and on, over the bosom of the deep, always bearing to the west, they have ultimately arrived at the spot from which they started. It is known also from this circumstance, that when a vessel out at sea is bearing towards us. the first point observable above the horizon is the top of its masts ; as it approaches the lower por- tions gradually become visible, until at last we perceive the full outline of the ship. Were the earth a level plane such could not be the case, for upon so smooth a surface as the ocean, when one portion appeared the whole would at the same time be visible, diminished of course in proportion to the distance. The glob- 40 OUTLINES OF ASTRONOMY. ularity of the earth's figure receives collateral illustration from that of the other heavenly bodies, for it is a law pervading nature that similar things shall mutually illustrate each other; hence, while an astronomical knowledge of our globe will enable us to understand certain particulars relating to other members of the solar system, they reciprocally furnish us with instruction con- cerning it. The aspect of the planets, seen through a telescope, is spherical, but independently of this the phenomenon of eclipses is quite sufficient to establish the fact, for the earth's shadow reflected upon the moon is always perceived to be round, as is also the moon's shadow cast upon the sun. A shadow always presents a faithful outline of the body from which it is projected. 4. The Motion of the Earth. It was remarked above (paragraph 3) that the earth is constantly moving. This follows almost as a consequence of its figure. Conceive of it as a globe poised in space and it is difficult to imagine how it could be exempted from mobility. The ethereal vault in which it is suspended is composed of elements so subtle and refined as to be destitute of any buoyant power sufficient to support the inert mass, where- fore motion becomes a necessity of its existence; but this simple fact is not adequate to the solution of the precision and reg- ularity observable in all its movements. These can be attributed only to the agency of certain fixed laws impressed on the original constitution of things by the Divine Creator. It is found by careful observation, assisted by ingeniously constructed instru- ments and other appliances, that the earth rotates upon its center as a revolving globe upon an axle, and with amazing swiftness, maintaining a perpetual whirl. In addition it is found that the sun, notwithstanding the appearance to the contrary, stands in relation to the earth as a fixed body. Although in reality it is not free from motion, yet it maintains the same general position in reference to this globe. In consequence of the relative im- mobility of the sun's position, the earth is the subject of a sec- ondary, which is a progressive motion round the central lumin- ary. Its primary or axillary movement is called its diurnal motion, because it is completed in the space of a day ; the sec- ondary or progressive motion is called its annual revolution, because its circuit is accomplished in the space of a year. These OUTLINES OF ASTRONOMY. 41 combined movements, which are unceasing, produce the com- mon illusion that the earth is a central body, about which the starry heavens revolve ; they also are the proximate causes of the succession of day and night, and the vicissitudes of the sea- sons. The beauty and utility of this arrangement will be ob- vious when we reflect upon these phenomena. Although these motions are continually carried on, we are not sensibly conscious of them. The case is somewhat similar to being shut up in a carriage which is traveling rapidly along a smooth road ; its motion is not then perceptible ; or when proceeding in a railway train, the external scenery appears to be rushing past us and we seem quite at rest ; or it is like the motion of a ship in smooth water. So it is with respect to the earth's movements and our unconsciousness of them. It may be mentioned here that the earth is no tardy traveler, performing as she does, according to the testimony of well-accredited investigators, her annual revo- lutions at the mean distance of ninety-two millions of miles from the sun in the short period of twelve months ; that is, at the rate of sixty-eight thousand miles per hour, and rotating upon her center in less that twenty-four hours, at the mean rate of 800 miles per hour. In her annual journeys she is constantly escorted by a fair attendant, the Moon, of which we shall now speak. 5. The Moon. The moon performs good service to the earth, independently of the supply of reflected light which she trans- mits. Her especial uses to the earth will be seen when we come to notice the tides. For the present we shall present the reader with a view of some of her general features. Her diameter is 2160 miles and she is the subject of a three-fold motion : i. The axillary, revolving upon her center in 27 days, 7 hours, 43 minutes, n seconds; 2. A local motion round the earth, at the distance of 240,000 miles, occupying the same period as the former, and constituting a lunar month ; and 3. A pro- gressive motion with the earth round the sun, performed in 13^ lunar months, comprising 365 days, 5 hours, 56 minutes, 57 seconds. She resembles the earth in not being a self-lumi- nous, butan opaque mass. The light she exhibits is not inherent, as might at first be supposed, but is derived from the sun and 4 2 OUTLINES OF ASTRONOMY. reflected in tremulous rays. When viewed with a telescope her disc displays a great diversity, one part being covered with bright spots and lines, and another part overspread with dark patches and shadows. The brighter parts of the moon are mountainous, as is proved by the fact of their casting shadows when the sun's rays fall upon them obliquely, and also by the ragged appearance presented by the interior illuminated border of the moon, an appearance which can only be satisfactorily accounted for on the supposition that the surface of the moon is not level, in which case the higher portions will be illuminated some time before the light reaches the level parts ; and it is ob- served that as the illumination proceeds, bright spots start up in advance of it, and when the moon is on the wane, these same spots continue to shine for some time after the surrounding sur- face is immersed in gloom. The mountains occur either singly, when they are generally of a circular form, and are called craters, or in groups, which are mostly annular, and form a sort of wall, inclosing a deep depression or plain, in which are situated one or more conical mountains. The craters are not unfrequently eight or ten miles in diameter, and some of the walled plains measure more than one hundred miles across. 6. The Sun. The solar orb is the great source and center of light and heat, not only to the globe which we inhabit, but also to several other bodies floating in the starry domains. In appearance, it is of nearly the same dimensions as the moon, but in reality its diameter is 414 times greater. The earth being 92,000,000 of miles from it, and only 240,000 from the moon, the former is nearly 400 times more distant than the latter; and both objects appearing of the same size, it follows, according to the well known law that the apparent size of an object decreases in the ratio of its distance, that it is also 414 times larger. Its diameter is thus computed as being 850,000 miles, which is more than 108 times that of the earth. Of its composition we cannot speak with any certainty. It is evidently an immense volume of luminous matter, but as to the specific nature of this matter, there are various opinions, the most probable of which is, that it consists of pure elementary fire, by which is meant that it is an ocean of elemental particles in a state O U TLINES OF AS TRONOM Y. 43 of perpetual activity. A curious phenomenon pertaining to the sun, is the appearance of a number of dark spots upon its sur- face, some of which are not less than forty thousand miles in breadth. From repeated observation of the spots, it has been conjectured that this vast orb experiences a rotary motion of 25^ days duration. Spots were perceived on the western margin ofhis disc, and were traced apparently across it, until they disappeared on the other side. From other observations it was thought that the solar disc accompanied the spots ; and after making the necessary deductions for the earth's change of place during the period of a transit of the spots, the time above stated was determined as the period of an axial motion. The precise nature of the spots has led to much speculation among astron- omers, some contending that they, are deep cavernous openings in a luminous atmosphere surrounding the sun, and that the solar orb itself is an opaque mass discerned through the open- ings; while others urge, and as we think most reasonably, that they are an incrustation produced from the solar matter, and contain the materials of which worlds are made. If the latter theory be correct, they might revolve round the sun without carrying it along with them, and hence, although the solar orb doubtless has an axial motion, the above calculation of its period may be erroneous. Be this as it may, it is quite certain that the glorious orb which the Creator has established to be the medium of communicating heat and light to his multiform .works, is a magnificent and highly important part of his creation. Without his genial warmth and effulgent beams, all nature would perish. When but partially withdrawn, how languid and torpid does she become ! assuming the shadow of death ; and at his reappearance, how joyous and animated an aspect does she wear! Deprived of its conservative influences of attraction, worlds would rush into a wild chaotic tumult, and eventually be destroyed. In all ages, the sun has been an object of peculiar regard ; venerated by the unlettered, with emotions of awe and adoration, and by the learned as a manifestation of the wisdom and goodness of nature's Author. And some deeply- searching philosophic minds have found delight in contemplating it as a type of the all-glorious Being Himself ; and its pro- 44 OU TUNES OF AS TRONOM F. ceeding heat and light as emblems of the divine love and wisdom which continually flow from God, to vivify, illuminate, and bless the human race. 7. The Planets. We have now spoken of the sun, moon, and earth a portion only of our solar system. On a starlight night, when the glittering firmament is radiant wiih loveliness, and eloquent with beauty, amid that solemn stillness so congenial to interior thought and pure aspirations, the inquisitive beholder may discern a few of the heavenly bodies adorned in greater splendor, and of somewhat more imposing magnitude, than ordinary stars. They are known as planets, being of an erratic nature, shifting their positions very conspicuously, The word planet, from the Greek, signifies a wanderer. The ever-pro- gressive movement of which they are the subjects, distinguishes them from the other heavenly bodies, which, from their apparent immobility, are named fixed stars. Another feature by which a planet is distinguished from a fixed star, is that the former is never seen to twinkle. Besides this, there are a few other planets claiming kindred with our own, which are invisible to the naked eye. These together with their attendant moons, compose the solar system, of which the sun is the central body, and to each of which he dispenses his invigorating and quicken- ing beams. The planets already discovered, amount to 56, and have been classified into two kinds, primary and secondary. The primary planets are all those which, like the earth, perform a revolution round the sun ; and the secondary, those which gyrate about their primaries, as the moon about the earth The latter, 18 in number, are called satellites, from a word denoting an attendant. The former are invariably known as planets or earths. Of these, twenty are, at present, familiar to us. In form, they are very similar to the earth, and likewise resemble it in their motions, rotating upon their centers, and revolving round the great luminary. The path described by a planet in its progressive journey, is termed its orbit. The orbits vary considerably in respect to distance from the central orb, and slightly in respect to figure. No two travel at the same dis- tance from the sun, nor in a precisely parallel plane. If it were so, disturbances would ensue. The planets move in a similar OUTLINES OF ASTRONOMY, 45 direction, from west to east, both in their diurnal and annual revolutions, and by their two-fold motion, every portion of their surface is successively, and at stated intervals, brought under the sun's influence. This is an infinitely wise provision. Let the contemplative eye turn where it may, it falls upon an evidence of Infinite wisdom, no less than of Infinite goodness. 8. Astronomers usually commence their description of the solar system with the planet nearest to the sun, and so proceed outwards, but some have adopted a different course, and be- ginning at the presumed boundary of the system have pro- ceeded towards the center, We prefer the former method be- cause it is most in accordance with the order of the discovery, and also because it is impossible to see that we have yet ascer- tained the boundaries of our solar system. 9. Mercury, the nearest to the Sun, is nearly 3,000 miles in diameter. Its daily motion is believed to be accomplished in 24 hours, 5^ minutes ; and its annual revolution occupies 88 days, describing an orbit round the central luminary at a mean dis- tance of 37,000,000 miles. It appears to the naked eye as a bright star ; but seen through a telescope, it is found to undergo increase and diminution, similar to the Moon. The cause of this will be apparent when an explanation is given of the phases of the Moon. Huge mountains are supposed to exist on the sur- face of this planet, some of which are much loftier than any upon the Earth. Owing to its peculiar position, relatively to the Sun and Earth, from its being within the orbit of the latter, it is visi- ble only for a short period soon after sunset or before sunrise. 10. Venus, the next in order, is a beautiful, lustrous body, often dazzling the eyes of the beholder. It is not much inferior in bulk to the Earth, being 7,800 miles in diameter. Its orbit, 68,000,000 miles from the Sun, is accomplished in 225 days, and its axillary revolution in 23 hours, 21 minutes, 19 seconds. Like Mercury, it passes through various phases, sometimes present- ing the edge only of its disc illuminated, and at other times its full face. The surface is variegated with mountainous districts, the principal of which are in the southern hemisphere. An at- mosphere has also been detected, and some thought an attendant moon was discernible, but this is difficult to determine, because 46 OUTLINES OF ASTRONOMY. when between the planet and our Earth, it would be hidden in the shadow of Venus, and when in any other position its illu- minated side would be beyond the sphere of observation. Venus is perceptible by the naked eye a little longer than Mercury, be- fore sunrise and after sunset. it. The Earth, that important planet upon which it is our lot to be placed, is the third in point of distance from the solar orb. Its diameter is 7,912 miles, and its circumference is about 25,000. The periods of its revolutions and its distance from the Sun have already been mentioned (par. 4). Its surface contains about 197,000,000 square miles. Of this, scarcely a third part is dry land, and not a tenth part is inhabited by man, although there are at present upwards of r, 000,000.000 human beings upon it. It is surrounded by an atmosphere whose density is propor- tionate to its altitude ; the pressure at the surface being equal to 15 pounds per square inch. This atmosphere serves to temper the solar rays, and to hold aqueous vapors in suspension ; and is found necessary for the support of animal life. An exposition of its manifold uses and phenomena belongs properly to meteor- ology and other sciences. We cannot speak with accuracy of the matter composing the solid globe, since man has never pene- trated much more than- a mile below the surface. Some have supposed it to be quite hollow, others believe it to consist of a fluid mass, either of molten metal, or fire ; while some have imagined it to be filled with water. That there is intense heat beneath the surface is plain from the existence of burning moun- tains, which belch out volumes of fire ; and boiling springs are prevalent in some parts of the world. The crust of the earth is found to be composed of many distinct layers or strata of earth and mineral substances, a description of which it is the province of geology to furnish. Its surface is adorned with a beautiful in- vestiture of floral, arborial and cereal productions ; for an account of which, systematically arranged, the sciences of botany and arborculture must be consulted. It is also the abode of some thousands of distinct varieties of animated beings, which minis- ter in various ways to the good of man, the head of all ; the sci- ence of natural history will delineate their several characteristics. Reflecting upon the peculiarities of our globe, we are impressed OUTLINES OF A STRONOM Y. 47 with the mutability of all things mundane. Scrutinize whatever point we may, there is a continual process of decay, renovation and systematic reformation. Everything seems destined, like the world itself, to perform appointed cycles for the production of certain special uses. Man is not exempt from these transfor- mations. The child advances into youth and youth into man- hood; and the man, after a few brief years, resigns his body to the tomb, where it undergoes the process of decomposition, and is dispersed into its primitive elements, and these elements en- tering into the composition of vegetable and animal structures, become again vitilized portions of other bodies. 12. Mars, the planet next in order, is a globe of 4,500 miles in diameter, rotating in 24 hours, 39 minutes, 21^ seconds ; and performing its annual revolution at the distance of 144,000,000 miles from the Sun, in the space of 686 days, 22 hours, 18 sec- onds. This planet is distinguished in the heavens by a red and fiery appearance. A surrounding atmosphere has been discov- ered, whose peculiar composition may possibly occasion the red appearance. Lying beyond the boundary of the Earth's orbit, it does not experience phases, so varied, as do Mercury and Venus. It is frequently seen gibbous. Towards its northern and southern extremities, large white patches are observable ; these are con- jectured to be masses of snow or ice, which remain unthawed during its long winter season. It is worthy of remark, as tend- ing to confirm this supposition, that they are not always visible, but only when the planet stands in such a relation to the Sun as would induce winter at those regions. It is also a well known law in optics that anything white, but particularly snow, will strongly reflect the solar rays. 13. The Asteroids or Small Planets. Proceeding onwards from the Sun, we come to a cluster of small planets, called, on account of their diminutiveness, Asteroids. Thirty-one have already been discovered. They describe orbits at no great distance from each other, but very irregular; they all experience a rotary motion. Their periods of revolution vary from 3 to 5 years. One only is visible to the naked eye. Some astronomers have conjectured that these are fragments of a disruptured planet, which originally traversed that portion of the heavens. They are named Ceres, 4 8 U TUNES OF A S TRONOM Y. Pallas, Juno, Vesta, Astrsea, Hebe, Iris, Flora, Hygeia, Diana, Parthenope, Oceanica, Victoria, etc. The first four were discov- ered from 1801 to 1807; and the others have been discovered since 1845. More will, doubtless, yet be added to the list. 14. Jupiter. This, the largest of all the planets, whirls in its appointed orbit at the distance of 496 million miles from the Sun, in the space of n years, 3 1 5 days, 8 hours, 58 minutes, 27 seconds; traveling at the almost incredible rate of 29,840 miles every hour. This immense mass, 90,000 miles in diameter, (which is eleven times that of the Earth), rotates in the space of 9 hours, 55 minutes, 33 seconds; at the average speed of 28,000 miles per hour. A pecul- iarity connected with this planet, which has not yet received a satis- factory solution, is the appearanceof a numberof darkstreaks sur- rounding it, in the form of belts, which are found to vary consid- erably ; sometimes appearing to be ruptured, and then vanishing entirely. Large spots have been observed in these zones; and when the belts have disappeared the spots have vanished also. From this, some astronomers have inferred that they are clouds floating in the atmosphere of the planet. The belts are supposed to be certain tracts of comparatively clear sky subsisting in the atmosphere, induced by peculiar atmospheric currents, some- thing like our trade winds, but not so variable, and, according to this theory, the spots are presumed to be the dark body of the planet seen through openings in the belts. Jupiter is favored with the attendance of 4 satellites, which are continually revol- ving round him, and accompany him in his annual progress about the Sun. His nearest moon revolves in an orbit of 259,000 miles from his center ; the second at 482,000, the third at 683,000 and the fourth at the distance of 1,202,000 miles. The periods of their revolutions vary from i day, i8j^ hours, to 16 days, 16^ hours. Theirorbital arraqgement is such that theprimary is never destitute of twilight. The smallest of these silent wanderers is larger than our moon, and each is subject to occasional eclipses. Jupiter is inferior to none but Venus in brilliancy ; and, in bulk. exceeds the Earth 1,300 times. 15. Saturn. This planet describes the next outermost circle round the Sun. It is a globe of about 78,000 miles in breadth ; has a diurnal motion, occupying 10 hours, 16 minutes, 19 sec- O U T LINES OF A S TRONOM Y. 49 onds; and a periodical revolution at the mean distance of 900,000,000 miles in 10,747 days, that is, nearly 30 years. This planet is less bright than all the other primaries, except Uranus and Neptune ; and, like Jupiter, is surrounded by a kind of zones, which, from the great fluctuations they undergo, appear to be a species of subtle matter floating round the body of the primary. A peculiar feature in reference to this globe is the existence of several concentric rings encompassing it. They consist of opaque matter, and are supposed to receive light from the solar orb, and reflect it upon the body of the planet. That the rings are constituted of some dense substance is evident from their re- flected shadow upon that side of the planet nearest the Sun and the shadow of the planet on the opposite interior side of the rings. The largest ring is about 200,000 miles in breadth. Saturn has S moons, one of which is of very recent discovery. These accompany the planet with so nicely adjusted regularity that every portion of its surface is kept enlightened by one or the other of them. They are of variable sizes and distances, the nearest being 11,400 miles, while the most remote is no less than 2,272,000 miles distant from the planet. The periods of their revolutions are proportionately diverse, ranging from i day to 79 days, 8 hours. 16. Uranus. Advancing in our outward travel, to a distance of 900,000,000 miles from Saturn, we come upon a member of the solar system which, till the year 1845, was considered the re- motest planet. Its diameter is 35,112 miles. It is, therefore, in- ferior to both Saturn and Jupiter, but is about eighty times the size of the Earth, Its axial motion has not been ascertained ; its periodical revolution, at 1,800 million miles from the Sun, oc- cupies 84 years. One of its years, therefore, would be equal in duration to an ordinary lifetime on our planet. It moves in its orbit at the rate of 15,000 miles per hour. On account of its great distance it cannot be distinguished from a fixed star without the aid of a magnifying power of 200 times. Four satellites have been discovered and two more are supposed to exist. Uranus was discovered by Sir William Herschel, father of Sir John Her- schel, in 1781. and was for some time known as the planet Her- schel. It was also called the Georgium Sidus, in honor of the 5 o OUTLINES OF ASTRONOMY. reigning monarch, George III.; but the name Uranus is now universally recognized. In the ancient mythology Uranus was the father of Saturn, as Saturn was of Jupiter, and Jupiter of Mars. 17. Neptune. This is the name given to a recently discovered planet which traces its path among the solitary fields of ether at the almost inconceivable distance of 3,000,000,000 miles from its solar center. It accomplishes its journey in about 164 years. Its diameter is computed at about 31,000 miles. The period of its diurnal motion has not been precisely determined. One at- tendant moon has lately been discovered, and it is supposed that there are others. Something bearing the appearance of an engirding ring, similar to the rings of Saturn, has been partially observed. 18. The discovery of this planet, so far removed from us in the regions of space, has perhaps done more to verify the mathe- matical accuracy of astronomical calculations than anything hitherto achieved. Long previous to its actual observation, its existence was surmised. Several astronomers had noticed the perturbations, experienced by Uranus in its orbital progress. At one period this planet was found more regular than at an- other. Supposing no disturbing cause existed, his precise posi- tion in any part of the heavens, at any given time, could have been predicted with certainty. Actual observation was not found to coincide with the prediction. From 1795 to 1822, his actual place was in advance of his computed place ; from 1822 to 1830 he was observed to retrograde, until, at length, the com- puted and observed positions agreed, and it went on gradually receding. Knowing there must be some cause for these disturb- ances, and, recognizing that law in dynamics, that masses of matter exert a reciprocal attractive force upon each other accord- ing to their bulk and distance, and finding that the influences interior to the orbit were not adequate to produce the perturba- tions witnessed, astronomers concluded there must be some huge body revolvinginanoutercircle, beyond the boundaries of Uranus. Some astronomers consequently betook themselves to the task of discovering, if possible, the position of the supposed extra- neous body, and two gentlemen in particular arrived at very OUTLINES OF ASTRONOMY. 51 nearly the same results, namely, Mr. Adams, an undergraduate of the University of Cambridge, and Monsieur Leverrier, a French astronomer. The latter, however, made the nearest ap- proximation to the truth, as to the position of the disturbing body, and proceeded further to describe its magnitude, the figure of its orbit, etc. He is considered, therefore, as justly entitled to the honor of the discovery. But all this was as yet only hypo- thetical ; the planet still remained to be seen. Leverrier had expressed himself upon the subject as follows : '' Theory and observation appear to contradict each other when Uranus is concerned the planet which gravitates on the confines of cur system. Well ! neither one nor the other is wrong ! In order to re-establish this agreement, broken in appearance, it only re- quires to admit the existence of a star of the same nature, but more distant, disturbing by its influence the regular movements of Uranus. This Star no one has seen, but it exists. I have meas- ured its distance, weighed its bulk, and estimated its diameter // is there, seek, and you will discover it! "Certainly," says Mon sieur Arago, in a paper read before the Academy of Sciences at Paris, "never did a more bold assertion receive a more striking confirmation. Monsieur Leverrier writes to Monsieur Galle, at 4 Berlin. The letter reaches him in the morning. The same night he points his telescope to the exact point of the heavens indi- cated by the French astronomer, and immediately, without any searching being required, he finds the predicted planet, which for so many centuries had remained hidden from us." This case affords an instance of the certainty of mathematical deductions. An object is physically observed from data furnished by one who, although he had not seen it, had intellectually discovered it. 19. It has been calculated that the mass of all the planets to- gether would not exceed a 6ooth part of the Sun's bulk ; and the area embraced within the orbit of the remotest planet yet dis- covered, comprises a region of space equal to six thousand million miles in breadth, and nearly nineteen thousand million in circumference. And this expansive system, comprehending within its limits so vast a region as to be scarcely appreciable to human intellect, what is it in comparison with the wide domains spreading all around and beyond in every direction ? what in- 52 O U TUNES OF AS TROXOM Y. deed but a mere speck in the great universe, a small item of the furniture of the heavens? Well might one of old exclaim, under a sense of its magnificence, "the heavens declare the glory of God, and the firmament showeth his handiwork." The compara- tive size and circuit of the planets, has been illustrated by Sir John Herschel, as follows : " Select a well-leveled field or bowl- ing green. In the center, place a globe two feet in diameter, to represent the Sun ; a grain of mustard seed will denote Mercury, placed on the circumference of a circle 164 feet in diameter, to represent its orbit ; and Venus will be denoted by a pea, placed on a circle 284 feet in diameter. The earth will be also a pea, on a circle 430 feet ; and a rather large pin's head, on a circle of 654 feet, shows Mars; grains of sand, on circles or orbits of from 1000 to 1200 feet, repre- senting Juno, Ceres, Vesta, Pallas, Astrea, and the other small planets recently discovered. Jupiter will re- quire a middling-sized orange for his representative, in a circle nearly half a mile across ; Saturn a small orange on a circle four-fifths of a mile ; and Uranus a full-sized cherry, or a small plum, upon a circle of more than a mile and a half in diameter." An ordinary plum v on a circle of two miles and a half, would represent Neptune. 20. A brief description of the planetary bodies composing our solar system, has now been given, from which it will be seen that in magnitude, the Earth is superior to 15, and inferior to 4 of the primary planets. What legitimate inference may we draw from this fact? Do these capacious globes exist simply for the good of mankind upon this Earth ? They resemble it in form, are governed by the same physical laws, are subject to the same mutations ; and are we not compelled to conclude that they exist for the same purposes ? As far as their light is concerned, they are of comparatively little service to us, nor have they any perceptible influence in maintaining the established order of things upon our planet ; some of them, too, are not discernable without the aid of magnifying glasses. What use, then, in the vast economy of nature, can they subserve ? That they have important uses to fulfill, it would be impious to deny, for ihe Creator has made nothing in vain. Have they been framed to OUTLINES OF ASTRONOMY. 53 display His omnipotence, and hence to exalt our conceptions of His glorious perfections? If so, our conceptions are only really elevated in proportion to our perception of their uses. Is not every reflecting mind conscious that everything is valued accord- ing to its estimated usefulness ? Viewing them as capacious seminaries expressly designed to people the spiritual universe with happy subjects, do we not assign to them the highest of all uses, and, regarding them in this light, are we not animated with emotions of the profoundest reverence towards that Divine Being, who is manifestly so great, not only in power, but in goodness which constitutes true greatness ? This view is quite compatible with analogical reasoning ; for, if this be the end of creation upon our Earth, those far distant spheres so much resemble ours in their physical properties, and in all that we know of them, that it must be predicable of them also. 21. Comets. These form a numerous class of celestial bodies, whose true nature and uses are at present involved in obscurity. A Comet is a fiery meteor, scientifically divided into four general parts : the nucleus, which is the most dense portion, being opaque ; the head, that is, the light part surrounding the nucleus; the coma, a lighter portion than the preceding, which forms a halo around the head ; and a tail, composed mostly of a long stream of light projected beyond the body of the comet. The matter of the tail is very much attenuated, and is quite transparent. Whether these fiery wanderers are really members of our system, is problematical. Three only have been ascertained to observe anything like a definite period and course of revolution round the Sun. Of these, the principal one is known is Halley's comet, whose revolution occupies 75 years. Its last appearance was in 1835, at the time which had been computed for it. An- other has been found to revolve in about 3^ years ; and it is worthy of remark, that, upon each return of this body, its period of revolution is found to lessen. Its orbit is, therefore, gradually becoming more circumscribed, or its velocity is increasing. A third comet has been observed to fulfill its revo- lution in 6% years, and it is rather remarkable that this has no tail. Another, which appeared in 1680, is assumed to have a 54 U TUNES OF AS TRONOM Y. period of 575 years. The few whose periods have been deter- mined with some degree of certainty, form but a very small number in comparison with those which sometimes appear within the confines of our system, and then are lost to view; some never more to reappear, and others at exceedingly long intervals and indefinite periods. One known as Leslie's comet was twisted by the action of Jupiter out of its proper orbit into a short ellipse, and, after passing twice round the Sun in such ellipse, was, by the same planet, twisted back again, and driven off into the depths of space, probably to revisit us no more. The orbits of all the comets are very irregular, approaching near the Sun, and then retiring to a great distance. About 150 of these heavenly visitants have been made the subjects of scientific investigation, but their true constitutions and capabilities still elude the keenest observation. When noticing their changes, the question naturally occurs, What are they ? Can they be earths in a state of formation, composed of light ethereal particles, a kind of fire-mist, which, gradually condensing, merges into vapory and earthly matters. Some have imagined them to be suns, in an incipient state of progressive formation. We must, however, leave them at present veiled in obscurity, believing that, as science advances, and the intellect of man becomes free to perceive and judge accurately, and his affections become hallowed and attuned to the right use of knowledge, all uncertainty will be dispersed from this as from other subjects, and the glowing brilliancy of truth will illuminate the whole of the works of God. 22. Having now traveled over so vast an area of nature's empire, it becomes us to retrace our steps, and note down a few of the most important phenomena associated with our terrestrial dwelling-place. In doing so, we shall find occasion to admire the advantages resulting from the beautiful construction of our little universe ; for, it is little compared with the boundless realms of the great Creator's works. In the smallest things of nature, we can see an epitome of the greatest; we shall find her amenable to laws impressed upon her at her birth, from which she cannot deviate ; they govern in the formation of an atom, as in the con- struction of a world. The same law which presides over the U TUNES OF AS TRONOM Y. 5 > globular form of the dew-drop, imparts rotundity to the globe itself. 23. Day and Night. These phenomena result from the Earth's rotatory motion. As already observed, she is perpetually whirl- ing round upon her center. To illustrate this, imagine a rod passed perpendicularly through the middle of the Earth, pro- jecting at the two extremities, upon which she turns, as a bobbin on a spindle. This imaginary rod is termed its axis, and the upper projecting point is the north, and the under the south, pole. Now it must be obvious that as the Sun is relatively a stationary body, and the Earth is constantly revolving upon its presumed axis, that portion of her surface which is now presented towards the luminary, will, erelong, be turned away from him. While presented to him, the solar light is received, and day is the con- sequence; when averted, there is a deprivation of light, and night ensues. < 24. The Inequality of Day and Night. The thoughtful learner will perhaps ask. If the foregoing be correct, why are the days and nights so unequal in duration ? We proceed to answer this inquiry. It must be remembered that the Earth is the subject of two kinds of motion, (par. 4) that during every moment she is spinning round upon her axis, she is at the same time progress- ing in a circle through the realms of space. A familiar illus- tration of these distinct movements is furnished by rolling a ball upon the ground, which, while it advances, is also revolving upon its center. The alternate diurnal changes, as we have seen, are the product of the axial movement, but the variable length of each depends upon the progressive or orbital motion. In her annual journey, the Earth continually shifts her position with respect to the Sun. But these local changes are not sufficient to account for the irregularity of day and night, for supposing the Earth's rotation to be performed always with the same velocity ; what difference could be made relative to light and darkness by her position in one part of her orbit more than at another? Why, then, are not the day and night always equal, since we find that they are so at certain seasons of the year. This, indeed, would be the case if our globe traversed its annual path in a perpendicular position, that is, with the north pole ever 56 OUTLINES OF ASTRONOMY. pointing upright from its orbit. But this is not the case. The Earth journeys onward with her axis always, in reference to her orbit, in a slanting direction, and maintains this situation throughout her annual revolution ; her north pole being pre- sented towards a particular point in the northern heavens. By this arrangement it is evident that during the progress of its circuit, no spot upon its surface can stand exactly in the same relation to the Sun for any length of time. At two periods of her course, (as will be shown when speaking of the seasons) she is so situated as to receive the solar beams directly upon her central portions, and this produces a day and night of equal duration all over the world; while at another period, her position is such that the regions about the north pole enjov perpetual light for some months, and at another period the south pole is similarly illuminated. 25. 7^i? Figures of the Earth's Orbit Explanatory of the Varia- tions of Day and Night. It has been found by patient observation that in performing her periodical revolution round the Sun. the Earth does not proceed in a horizontal plane; that is, she does not progress in direct line round the center of the Sun, but de- scribes a slanting circle. At one portion of her orbit, she is a little below the horizontal line, or the Sun's equator ; and at the opposite point she is a little above it. Her .situation at these two stages of her progress respectively constitute her longest and shortest day. It is clear that while located at the lowest point, the northern portion of the globe is more immediately receptive of the solar rays, while the southern portion will remain in com- parative obscurity, and the extreme south will be involved in total darkness. This point is attained on the 2ist of June, when the day, in Great Britain, is more than 16^ hours long. The north pole now enjoys an uninterrupted day of some months' duration. Rising steadily from this her lowest position in the direction indicated, the Earth in due time comes to that portion of her orbit where the horizontal and oblique lines intersect each other, and here a complete half of her surface is presented to the Sun ; hence results an equal day and night throughout the globe, the Sun rising at six and setting at six. Proceeding on- ward, daylight in the north gradually decreases, because the OUTLINES OF ASTRONOMY. 57 northern hemisphere is more and more averted from the solar beams, until arriving at the highest point, the boundary of her oblique wanderings, which happens on the 2ist of December, the shortest day is experienced by those parts north of the equator, and the extreme south is illuminated with unceasing light. Having attained this altitude (which is her highest position to the inhabitants of the south), she commences her descent, and step by step, goes down the inclined plane on the opposite side of the Sun, till again reaching the point where she crosses the horizontal line, which is the Sun's equator, her surface is illumi- nated from pole to pole, and an equal day and night of twelve hours is again realized. Proceeding downwards in her travel, she finally arrives at the point whence we started ; her northern hemisphere is then lighted up, variegated beauty adorns its surface, and it once more rejoices in a plenary reception of the solar rays, while the south pole is again passing through a long and wintry night. How beautifully does all this shadow forth the changes of human life ! How eloquent is nature, to the soul attuned to its divine harmonies ! What lessons of fertile wisdom may be gleaned from the movements and positions of the terrestrial globe ! 26. Phases or Changes of the Moon. The Moon revolving upon her axis presents every portion of her surface towards the Sun at stated intervals, and thus receives his light, a portion of which is reflected or thrown back from her illuminated disc; the portion so reflected is moon-light. But we find that the intensity of moon- light varies considerably, and at times is entirely absent, on account of the moon being partially or wholly invisible. The aspects presented by the Moon during her several changes, are called phases, from a Greek word signifying appearances. When she is in that part of her orbit which lies between the Sun and the Earth, her illuminated side is hidden from view. She is then invisible, and we have no moon-light, and the Moon is said to change. As she proceeds in her circuit, a portion of her luminous surface appears in the form of a bright edge. We then have new-moon. This bright edge gradually widens, as the Moon advances, till half her disk is exhibited ; when we have what is called half-moon. She travels on and on, until, arriving at the 58 . OUTLINES OF ASTRONOMY. side of the Earth most distant from the Sun, the whole of her illuminated surface is visible, and there is full-moon. She then goes through a similar process of diminution. That the Moon, like the Earth, is an opaque, and not a self-luminous, body, is evident from the nature of eclipses, upon which we shall now offer a few remarks. 27. Eclipses. An eclipse is a total or partial deprivation or obscuration of light, either from the Sun or Moon. In some total eclipses of the Sun. the darkness has been so great as to exhibit the stars at noon-day. An eclipse of the Sun occurs when the Moon gets between it and Earth. An eclipse of the Moon happens when the Earth comes in a direct line between it and the Sun. A solar eclipse can never occur but at the time of the Moon's change, nor can one of the Moon take place at any other time than when she is full. Both solar and lunar eclipses can be predicted with perfect accuracy. To understand the causes of an eclipse it is necessary to refer to par. 25 ; for the Moon does not travel round the Earth in a horizontal plane. If it were so, there would, of necessity, be two eclipses every month, one lunar and one solar ; whereas it is well known that although there must be two of the Sun annually, yet there may be no eclipse of the Moon in the same year. The phenomenon is only explicable by the real motion of the Moon about the Earth being the same as that of the Earth round the Sun, namely, in a slant- ing direction. This oblique line, is called the ecliptic, because it is only when a body is interposed in some portion of this track that an eclipse can take place, and then it can only happen when the intervening body is at that point where the orbits of the Earth and Moon intersect each other in a right line with the Sun. Now if the Moon were in such a position that a right line drawn through its center would strike the center of the Sun, then the Sun would be hidden, except a portion which would be seen en- circling the Moon. This is called an annular eclipse. Suppose the Moon to be on the opposite side of the Earth, the latter, being so much larger than the Moon, would intercept so many of the Sun's rays as to obscure its entire disc, and hence results a total lunar eclipse. The number of eclipses vary from two to seven in the year, and it is found that the Moon has to perform U TLINES OF AS TROXOM Y. 59 233 monthly revolutions, before she enters into the same position with the Sun and Earth, in which she is at any given time. These occupy about nineteen years; so that there is a regular cycle of the movements of Sun, and Moon, and Earth of about nineteen years' duration. 28. Eclipses of the Satellites. The attendant moons of other planets are ascertained to be subject to eclipses similar to our own. Jupiter's moons have been observed to experience them very frequently, and they can be predicted with certainty. They present a rather curious appearance, the eclipsed satellite seem- ing to be suddenly obliterated from the firmament and as sud- denly re-appearing. The eclipse of other satellites has been observed. 20,. Tides. These, whatever may be their cause, form an im- portant feature in the Creator's works, and manifest great design and adaptation in their arrangement. We all know how soon stagnant water becomes corrupt, and unfit for the purposes of life. If the waters encircling the Earth were to remain sta- tionary for any length of time, a decomposing process would go on, engendering noxious and miasmatic vapors and thus loading the atmosphere with subtle poison. To obviate this, is one of the uses of the tides. By the continual ebbing and flowing of the waters of the ocean the salubrious element is preserved in a purer condition, adapted to man's necessity. 30. There are two general daily ebbings and flowings of the waters, the interval between each rising being 12 hours, 25 minutes, so that two complete tides go through their course in about 24 hours, 50 minutes. Hence, as a day comprises only 24 hours, the time of high water is about 50 minutes later at any particular place on each succeeding day. The tides are found to differ considerably in elevation, the mean high-water mark being five feet above the level, but sometimes rising to seven, and at other times depressed to three feet only. Astronomers have attributed the tides to solar and lunar influences, but more especially to the influence of the Moon. The theory generally accepted is as follows : 31. Cause of the Tides. In agreement with that law by virtue of which falling bodies are precipitated to the Earth, and which 60 OUTLINES OF ASTRONOMY. is -called the attraction of gravitation, it is argued that large masses of matter floating in space are mutually attracted towards each other, and that thus the Sun and Moon exert an attractive force upon the Earth ; but the water being a fluid mass, and consequently more mobile, presents less resistance to the disturbing action, and is therefore drawn out of its place to a greater extent than the solid matter, by the attractive influence of the Moon. [And thus are caused the tides : the Spring-tide when the Sun and Moon are on the same side or opposite sides of the Earth ; Neap-tide, when the Sun is quarter way round from the Moon.] A peculiarity worthy of remark is, that the water does not reach its highest point till three hours after the Moon has gone over the spot. This is imputed to the law of inertia, or the tendency which everything has to remain in the condition in which it is placed. When this inertia is overcome, the waters go on rising until another counteracting influence causes them to abate. The periodical return of the tides tends very much to confirm this theory of the Moon's agency. It was said that two whole tides occupy 24 hours and 50 minutes ; this is exactly the period required for the Earth to be brought into the same posi- tion with respect to the Moon from any given time; she, \\hile the Earth has rotated in 24 hours, having traversed a 2Qth part of her orbit. 32. The Zodiac. For practical purposes, astronomers consider the starry heavens as a vast concave encircling the sun at an equal distance all round. For the convenience of studying astronomy, they have imagined a horizontal line to be drawn across this concave, passing through the Sun's center from east to west. This is termed the equator, because it separates the celestial sphere into two equal halves, the upper one of which is called the northern hemisphere, and the lower one the southern hemisphere. The planetary bodies, the Earth included, do not travel, as already shown (par. 24), in the direction of the horizontal line, but inclined a little from it, forming in their orbit the ecliptic circle. A large belt has therefore been supposed to be drawn on the heavens, of sufficient breadth to include the orbits of all the planets. This imaginary belt, which is studded with stars, is known as the zodiac. Directly along its center O i * TLIXES OF AS TROXOM Y. 6 1 lies the Earth's path, and on either side of this, and sometimes crossing it, the other planets roll onwards in their appointed courses. To form a conception of the space occupied by the zodiac, it is necessary to be acquainted with the artificial di- visions of the firmament. 33. Divisions of the Celestial Sphere. The vast ethereal con- cave before mentioned, has been divided into 360 equal parts, or segments of a circle, called degrees, 180 of which are on each side of the equator, north and south. In conjunction with the equatorial line, another imaginary line, passing perpendicularly through the Sun and starry firmament, divides the celestial globe into four quarters, each of which is thus composed of 90 degrees ; a degree is subdivided into 60 equal parts, called seconds. These divisions of the circle are thus denoted, 8* 15' 30", signifying 8 degrees, 15 minutes, 30 seconds. The space allotted to the zodiac, in which the planets revolve, is about 16 degrees, that is, 8 degrees on each side of the ecliptic, or the path traveled by our globe. Its uses are to determine the position of the Earth, or any planet, and to exhibit the altitude and declination of a star at any specified time, these being all calculated with reference to the ecliptic line. 34. Signs of the Zodiac. The imaginary belt or ring already spoken of, is divided into twelve equal portions, each containing 30 degrees, called the signs of the zodiac. Three of them are respectively in the northern, eastern, southern, and western quarters ; and to distinguish them, they have received a nomen- clature from a fancied resemblance which the stars lying among them, seemed to bear to some terrestrial object. Thus, one group of stars was supposed to bear some resemblance to the outline of a ram ; hence that part of the zodiac lying imme- diately beneath the group was named the Ram, and so on. The names of the twelve signs, in Latin and English, are as follow : Aries, the ram; Taurus, the bull; Gemini, the twins; Cancer, the crab; Leo, the lion; Virgo, the virgin; Libra, the balance; Scorpio, the scorpion; Sagittarius, the archer; Capricornus, the goat; Aquarius, the water bearer; and Pisces, the fish. The Earth passes through one of these signs every month. 35. The Seasons. The phenomena of the seasons conclusively 62 U TLIXES OF AS TKOXOM Y. establish the main facts of astronomy ; they are precisely such as would result, reasoning from first principles, assuming the figure, aspects, and motions of the heavenly bodies to be what they really are. Upon no other theory than the true one could they be intelligibly and rationally demonstrated, and from the progress of modern sciences they are capable of a simple and beautiful explanation. The chief distinguishing characteristics of the seasons consist in the various degrees of temperaiure and light. The cause of the variations with respect to the light, is shown in par. 25. The cause of the thermal diversity is very similar. As light depends upon the existence and presence of the solar beams, so does heat. There is, however, this important difference between them ; light, when absorbed is suffocated, and hence, is not perceptible Icng after the absence of the light- giving body. It is otherwise with heat; this, when absorbed, is retained for some time, and is given off by radiation, hence, the warmth of night sometimes equals, and even exceeds, that of day. This, indeed, is a wise provision of the Creator; for were there a sudden and abrupt transition from the glowing and fructifying warmth of day to a cold temperature at night, vege- tation would be destroyed, and the autumnal fruits would perish, for cold is uncongenial to their perfection. 36. Causes of the Variations of Temperature. By variations we do not mean those finer shades of heat and cold which depend greatly upon atmospheric conditions, but those larger and more general diversities which originate from the mutual aspects of the Sun and Earth. The Earth passing along the central line of the zodiac (par. 32), completes her periodical course in twelve calendar months, during which time she has experienced all her thermal vicissitudes from the lowest degree of cold to the highest degree of heat. Starting from that portion of the zodiac marked as Libra, on the 2ist of March, when the spring quarter com- mences, she progresses through Scorpio and Sagittarius to the first point of Capricornus, when the spring quarter terminates, and the summer quarter begins on the 2ist of June. She then travels through three more entire signs of the zodiac, constitut- ing the summer quarter, and arrives on the 2ist of September at the first point of Aries, when the autumnal quarter is entered. UT LINES OF AS TRONOM Y. 63 Passing through three signs more, and coming to Cancer, the autumn is completed, and -winter commences on the 2ist of De- cember. Three other signs yet remain to be traversed, which, when accomplished, brings her to Libra, the point whence she started. Astronomers generally speak of the Earth's progress according to the apparent path of the Sun through the starry sphere; they then commence the annual course with the point Aries, because that is the sign of the zodiac in which the Sun appears to be located when the Earth begins her journey at the commencement of spring. There is, however, no absolute neces- sity for this We have, therefore, begun with the more natural because actual, position of the Earth in the point of Libra. Now, although this is the actual progression of the globe along the wide extended fields of ether through which her path lies, giving rise to that beautiful succession of seasons which is so admirably adapted to the requirements of a terrestial world, it must not be supposed that the whole Earth is at any one time in the enjoy- ment of spring, and at another period immersed in the depths of winter, etc. No ; from the combined effect of the inclination of her axis, and her annual progress round the Sun, the opposite seasons of summer and winter, are experienced at the same time in the northern and southern hemisphere. 37. During its annual revolution, the Earth gyrates in such a manner as always to have the Sun vertical in some part of the ecliptic; that is, the solar rays always strike some point of her surface embraced within the limit- of the ecliptic, in a perpen- dicular direction ; the space so inclosed is therefore called the torrid zone. It extends to 23 1-2 degrees north and south of the equator. The day and night within this boundary are of nearly equal duration all the year round, and the temperature is main- tained at pretty nearly an equal state. The two circles at the poles are termed frigid zones, the word zcne, from the Greek, signifying a belt, and frigid, cold (as torrid signifies burning or scorching), because in these regions the greatest cold prevails. They comprise a space around each pole of 23 j degrees. The lines which bound the ecliptic are named the tropics, after a Greek word which means to turn or change, because this mark points out that the Earth has gained her highest and lowest positions 64 O U TLIXES OF A S TROXOM Y. respectively, and thence begins to ascend and descend. The spaces between the frigid zones and the tropics are called the north and south temperate zones, because in the regions lying within these circles, the heat is never very intense, the sun's rays shin- ing obliquely upon them. The numbers round the circle fin a map of the Earth) indicate the 360 degrees into which the circum- ference of the globe has been divided ; the equatorial line girding the Earth, has also been divided into a similar number of de- grees ; of these we shall have occasion to speak more fully when treating of the natural divisic ns of lime. It will be seen that there is at all times a decrease of temperature, from the equator towards each pole, but the variable intensity of heat and cold is regulated by the Earth's progress in her periodical orbit. 38. Another point necessary to be mentioned, is the irregu- larity of the Earth's distance from the Sun. She does not travel round the Sun in a perfect circle, but her orbit is that of an ellipse, in which the Sun is located nearer to one end than the other. Our winter occurs when the Earth is nearest to the Sun. The reason why we do not experience a greater amount of heat at that season, is because the portion of the globe upon which Great Britain is situated is turned so much aslant from the Sun as to catch his lays but very indirectly. But it is found that the southern hemisphere which is then so immediately receptive of the solar beams does not experience a greater degree of heat than the ncrth when similarly receptive at a much greater dis- tance. How is this to be explained? Simply thus : as the Earth approaches this portion of her orbit she gradually accelerates her speed, and goes on increasing it till she arrives at the turn- ing point, when she begins to slacken until she comes to her mean rate, hence it is found that the winter half-year is accom- plished in eight days less than the summer half. By this in- creased rate of velocity, the Sun is prevented from being so long above the horizon as he otherwise would be, and thus his heat- dispensing power is proportionately diminished. Were it not so, it is supposed that the southern portion of the globe during our winter season, would be quite unfit for the purposes of life. That the increased velocity diminishes the reception of heat, may be made familiar to any one by the aid of a common ther- O U TLIXES OF A S TROXOM Y. 65 mometer. Let it be attached to a cylinder and turned slowly round before a large fire, noting the degree of heat; then let it be turned swiftly, and it will be found that the temperature di- minishes in an equal ratio to the increased velocity. This heai- rtceiving process is very different from the heat-prc during process ; for, in the latter, the more rapid the motion, the higher is the temperature raised. The effect would be the same if the ther- mometer were carried round the fire, to represent the earth's orbital motion. 39. We may here for a moment pause to moralize. The sea- sons have been wisely ordained. They minister not only to man's outward necessities, but also to his inner being, to the activities of thought and affection. They speak of an overruling Providence, whose guardianship extends to the meanest of created beings, whose laws are immutable and all-pervading; they speak of order, " heaven's first law," of equity and bene- ficence ; for in nature there is no fortuitous or chance occurrence, no capricious partiality or selfishness. The uses intended by the succession of the seasons are of universal application ; they exist for all. Poets and philosophers have thought upon this subject, and given utterance to their musings. Some have traced an analogy between the seasons and the four general periods of human life, comparing spring to childhood, summer to youth, autumn to manhood, and winter to old age. There is indeed a joyousness and freshness about the spring which will well typify the mirthfulness and bouyancy of childhood's happy state, while in the activity and ardor of the youthful temperament there is something of the busy life and genial warmth of summer. There is also in the man, with his increased capabilities for use- fulness, something akin to the richly laden autumn, with its plenteous stores of mellow fruit and grain, proffered to the will- ing and receptive hand. And in winter, too, the season of decay and apparent death, the time of withered leaves and darksome clouds, we may trace a resemblance to the last period of mun- dane life, when the powers of nature are fast waning, the natural energies are dormant, exterior adornments lose their fascination and attractiveness and all outer things are much obscured, and there is general preparation for a season of resuscitation, in a 66 OUTLINES OF AS TRONOM Y. new world of life and beauty. Others admitting this exterior analogy between the seasons and the stages of man's earthly existence, go deeper and descry a correspondence between the uses of the seasons and the interior states of mental being, states of affection, and variations of both. Thus, a wintry mental state, say they, is that condition of the mind in which the affections are cold, because not warmed by love to God and man, and the thoughts are obscured because not illuminated by rays of genuine wisdom ; thus the mind is averted from the only source of spiritual light and heat, and, in reference to the Divine Being, is torpid. Again, it is springtime with the soul when it is awakened from its dormant state, when the affections begin to bud forth under the influence of new life, when the mind turns toward the Creator of all good, and is disposed to receive His light-imparting instructions ; when, like nature, it is quickening for the coming produce. In its summer season it is still more turned to the heavenly source and parent of light, and is much more receptive of His vivifying love and illustrating wisdom, whence proceed the fruits of faith, and the beatifying works of charity; and then succeeds its autumnal state, in which the heart overflows with gratitude to God and love to man, its fruits are mellow, ripened by'celestial heat, and matured by experience. This is the soul's harvest-time. Happy all who are in such a state. 40. General Divisions of Time. Time is duration, which can only be measured by motion ; if all things were stationary and inert, time could have no existence. It is of three kinds: Mean or equal, that measured by clocks ; true or solar, that indicated by the apparent movement of the Sun ; and sidereal, or that which results from the position of the fixed stars. The first, which is a division of the day into 24 hours, is purely conventional, but at the same time well-adapted for practical purposes. The second and third are natural. 41. Sidereal 7'ime. This is determined by the earth's relative position to any fixed star. Although it is customary to say that the Earth rotates upon its axis in 24 hours, this is incorrect ; the fact is, it performs its entire revolution in 23 hours, 56 minutes 4 seconds. The fixed stars being located at an immense distance OUTLINES OF A STRONOM Y. 67 from the Earth, its orbit is so small in comparison with their remoteness, that, in respe.ct to them, it would seem to have no other motion than its diurnal one; hence it is thai any one of them which may be selected, will appear to rise regularly 3 minutes 56 seconds earlier every day ; this being the difference between the sidereal day and that of 24 hours. Now this daily difference amounts, in the course of a year, to almost another sideral day; consequently, when the Earth has performed an entire revolution round the Sun, and arrived at the point in the heavens from which she commenced her .annual journey, in a period of 365 days, 8 hours, 9 minutes, II seconds (reckoning 24 hours to a day), she has made 366 entire revolutions upon her axis, thus making the sidereal year to contain 366 days. Although this is the most precise method of computing time, on account of the stars not shifting their positions in reference to the Earth, as the Sun does, it is, however, not so convenient, nor practical, as the solar measurement ; the latter is, therefore, that generally adopted. Let us then see in what this differs from the former. 42 Solar Time. This, which is sometimes called astro- nomical time, is reckoned from noon to noon, and would perfectly co-incide with siderial time if the Earth had no other movement than the axillary ; but in pursuing its annual course, it is propelled along its circuit at the rate of nearly 1,600,000 miles per day. This must produce a considerable difference between the solar and sideral day, as some portion of time must necessarily elapse after the Earth has completed its rotation, before any particular spot upon its surface would come under the mid-day Sun, as it was the day previous. Such we find to be the case, and hence true solar time varies very little from that of the clocks, the greatest difference never exceeding half a minute in the 24 hours. At four periods of the year they are similar, hence the application of the term mean time. Owing to this slight variation, the solar mid-day, which is determined by the Sun's having attained its highest point in the heavens, is sometimes 16^ minutes earlier, and sometimes 14^ minutes later, than 12 o'clock mean time. The clock is then said to be so many minutes slower or faster than the Sun. These are the extreme points of variation. 68 UTLINES OF AS TRONOM Y. 43. Cause of the Difference of Time in Different Parts of the World. An observer upon a high eminence will find his vision bounded in every direction by the sky : the sky-line which thus bounds his vision is called the horizon. The apparent path of the Sun is from the east to the west. A line drawn over-head, midway between these quarters, is called the meridian, and when the Sun has arrived at this point, he has attained his highest position, and is consequently half way across the horizon, and is said to be in the meridian : this determines mid-day. At all other places, the time varies from noon to midnight, and from midnight to mid-day. To render this intelligible, certain lines have been drawn on artificial globes, in a direction from north to south, called meridians; when the Sun is immediately over one of these lines, it is then mid-day at ail places through which the meridian passes. Now the Earth being a revolving globe, with its'surface divided into 360 equal parts, and the day being divided into 24 hours, it follows that 15 degrees, must pass under the mid-day Sun every hour, for 360 divided by 24 gives 15 as a quotient, consequently when it is 12 o'clock at noon at any particular place, say London, it is one hour before mid-day or n o'clock at any spot 15 degrees west of London, and one hour after mid-day or I o'clock at any place 15 degrees east; as, for instance Berlin. And so traveling round the globe in a westerly direction, with the watch set to London time, we should find the clocks an hour later for every 15 degrees we proceeded. A degree at the equator is 60 geographical, or about 69 English miles. Of course, as the Earth is globular, the degree diminishes in proportion as we approach either the northern or southern regions; therefore, in traveling a given distance in an easterly or westerly direction, either north or south of the equator, a greater variation of time would be observable than upon the equator itself The meridians are also employed by geographers to compute distances, the distance, east or west, being called so many degrees east or west longitude; and north or south, so many degrees north or south latitude. For the pur- poses of precise measurement, each degree is divided into 60 minutes, and each minute into 60 seconds, as in the celestial sphere, (par. 33.) O U TLI.VES OF A S TRONOU Y. 69 44. The Calendar. The calendar is a table of the days, weeks, months, etc.; and was instituted with a view of reducing time to something like a standard. The Roman calendar, from which ours is derived, at first divided the year into ten months, the total number of days in which amounted to only 304. It was soon discovered that the civil year, as thus constituted, was shorter than the solar year, marked by the succession of the seasons; two additional months were then added to the year, and the 12 months were made to consist of 29 and 30 days each alternately, thus comprising 355 days; and that the civil might equal the solar year, a month was added every two years. This was found extremely inconvenient, wherefore, Julius Caesar undertook to reform the calendar, and made the year to consist of 365 days, and, to bring in the surplus hours added a day to every fourth year, which was in consequence called leap- year. By this arrangement there is an excess of a few minutes annually, which, in the course of 1,600 years, amounted to ten days. Pope Gregory XIII, in order to remedy this, decreed that the 366th day of every leap year, which commenced a century should be omitted, excepting that of every fourth century, which would compensate for the slight loss under the former arrangement To remove the loss which had been already sus- tained, from the time of Julius Caesar till 1582, ten days were at once struck off from the calendar, thus originating what is termed New Style. The New Style was not adopted in England till 1752, when, to make up for the accumulated loss, eleven days were struck off, and the day following, the 2nd of September, was called the I4th. Russia and Greece are now the only countries in Europe which retain the old style: the difference between their time and ours amounts now to 12 days. Our civil year still exceeds the true one by a small fraction; to rectify this it is necessary that another leap-year should be omitted in every 4,000 years. 45. Origin of the Names of the Months. January was so named in honor of an idol called Janus, which was worshiped by the Romans, and whose temple was kept open during the time of war, and closed in times of peace. It was fixed as the first month by Numa Pompilius. February is so called from 70 O U TUNES OF AS TRONOM Y. Februa, the name of a feast held by the Romans, in which they offered expiatory sacrifices in behalf of deceased persons. Feb- ruus is the Latin for Pluto, the god of the infernal regions. March, which, before the time of Pompilius, was considered the first month of the year, was named in honor of Mars, the god of war. April i 1 -, derived from the Latin Aprilis. iromaperio, I open, and is supposed to have been given to this month because at this season the Earth opens her bosom, as it were, for the pro- duction of vegetables and flowers, fruits and farinacia, etc. May is generally considered to have received its name from Maia, the mother of Mercury, who, Roman legends affirm, was sacrificed on the first day, and to whom oblations were to be offered dur- ing the month. June. There are two opinions respecting the origin of this name. Some say that it is from Junius, because this month was dedicated to the service of Juno, a heathen goddess; others that it is iromjuniores, the name given to the young men who had fought for their country; certain feasts in honor of them being held during this month. July, from the Latin Julius, was thus named in honor of Julius Caesar. Before his time it was known as Quintilis, that is the fifth month, reckoning from March. August is from Augustus, in honor of Augustus Caesar. It was formerly called Sextilis, the sixth month. September is from septem, seven, it being the seventh month from March. October is from Octo, eight, the eighth month. November is derived from Novem, nine, as this was the ninth month. December is from decent, ten, which was the tenth month from March. 46. Origin of the Names of the Days. The names of the days are all of Saxon origin. Sunday is so named from a Saxon idol of the sun which was worshipped on this day. Monday was a day set apart for the adoration of an idol of the moon, and was originally called Moonday. Tuesday had its origin in the Saxon word Tuisco, the name of a hero who was venerated by the ancient Germans as the founder of their nation. They be- lieved that under his auspices they were safely conducted from the confusion which followed the building of the tower of Babel. Wednesday is so called in honor of Woden, the Saxon god of battle. It was at first Wodensday, and eventually O U TLI.VES OF AS TRONO.M Y. 71 became abbreviated to Wednesday. Thursday is from Thor, an idol adored by the Teutonic people as the god of thunder. His worship was celebrated on this day. The transition from Thor's day to Thursday is not very great. Friday \s from Friga a Saxon idol representing both sexes. He was the supposed giver of peace and plenty, and the inspirer of the love of the sexes. This day was dedicated to him. Saturday is from Seatfr, an idol who was supposed to control the productions of the Earth, to in- spire the Saxon love of freedom, and to promote concord and unity. 47. The Sidereal System. Our preceding observations have had exclusive reference to the members of our solar system. \Ve will now take a glance at the regions of space surrounding it. It must be obvious to all that the few bodies already de- scribed, form but a very small fraction of the starry universe of that portion of it, rather, which is visible to us ; and this, perhaps, in comparision with that which is invisible, is as a drop to the ocean. The stars visible to the naked eye are few indeed compared with the number revealed by the telescope ; and with every increase of telescopic power, hosts of new objects are found to adorn the expanse of the material heavens ; which, but for this agency, would remain forever hidden from our view. The discovery of distant and still more distant members of the starry heavens, may go on as science advances, but, shall we ever be able to say that we have penetrated to the boundaries of space ? The members of the sidereal system are innumerable and their distances inconceivable. Athough incapable of cal- culation and measurement, some of them present features which show that they are of a kindred nature to our sun. If so if they are self-luminous orbs, for what purpose, as it respects our- selves, do they shine. This question is answered by a supposi- tion, not entirely destitute of evidence, that each sun is the center of a system of revolving worlds, of which our world and our solar system will afford a type. The evidence upon which this supposition, at present, rests, independently of analogical reasoning, is the long-observed phenomena of stellar changes. Many stars have been found to vary considerably in luster; at one time attaining to a certain degree of brightness, and then 72 OUTLINES OF AS TRONOM Y. becoming comparatively dim ; and these variations are found to observe regular periods. Thus the changes in one star occupy rather less than three days. Another passes through its suc- cession of changes in a period of six days and nine hours ; while another decreases in brilliancy until it gradually becomes in- visible, and then as gradually resumes its original splendor, occupying in these changes, eighteen years. Many more might be enumerated, but these are sufficient to illustrate the phe- nomena. Now as the position of these stars in the heavens remains the same during all their changes, no orbital motion or progression in space is adequate to account for their irregular brightness. The most reasonable conclusion, therefore, appears to be, that certain opaque bodies, of great magnitude, are re- volving round the stars, and according to their position in their orbits, sometimes intercept a portion of their light, and some- times entirely eclipse them. An eminent astronomer of the present day believes that he has observed attendant bodies con- tiguous to some of the brighter stars, shining, probably, by reflected light. 48. The Fixed Stars. The most obvious feature distinguish- ing the stars, is their relative brilliancy. Some are remarkably bright, while others are very faint. From this circumstance, astronomers have been enabled to classify them into different orders, and speak of them as stars of the first, second, and third, up to the sixteenth magnitude. There are about 24 of the brightest stars included in the first magnitude, between 50 and 60 of the second magnitude ; and the third comprises about 200 of smaller and less brilliant ones. The number of stars that have been registered, as far as the seventh magnitude, amounts to nearly 15,000. Those of the fifth are the smallest that can generally be seen by the naked eye, though sometimes on a particularly clear night, a few of the sixth degree may be in- distinctly seen. The stars exhibit not only a different degree, but a different kind of luster. Their rays differ not more in intensity than in kind. One shines with a white silvery light, while another has a ruddy glow. Some are red, others green, or yellow, or blue. These varieties of color are, perhaps, not intrinsic to the star, but are the result of optical illusion. Al- OUTLINES OF ASTRONOMY. 73 though it is customary to speak of the stars as fixed^ yet this is not strictly correct ; for, though they have no perceptible motion, they are supposed to have a progressive motion through space. 4g. Binary Stars. These form a curious and numerous class of heavenly bodies. They are called binary or double, not merely because they are are found lying close to each other, but trom their mutually revolving about one another, in regular orbits . and determinate periods. Their nature is, at present, involved in obscurity. Above four thousand have already been catalogued, and of these, several have been subjected to obser- vation for the purpose of ascertaining their periods and orbits. Some of those stars which appear as one to the naked eye, are resolved by the telescope into two distinct stars. At first, they were supposed to be in close proximity, or that one was far be- hind the other, almost in a right line. These opinions were soon dispelled by the application of telescopes of sufficient power, which showed that they revolved round each other. Their orbits appear to be similar to those prevailing in our system, namely, the ecliptic. 50. The Constellation. When prosecuting researches among the stars, great difficulty and perplexity were frequently oc- casioned by the want of recognized points to guide in the search. At an early period, astronomers learned this from experience, and were led to remove these sources of error, by conferring names upon certain clusters or groups of stars, and by delineat- ing them upon maps, or artificial globes. These names were generally applied from a fancied resemblance which the clusters bore to some well-known object. Thus, a number of stars are found grouped together in such a manner as to suggest the out- line of a bear. This cluster has, therefore, been denominated the Bear, and so in other cases. These fanciful groupings are what are termed constellations. Their chief use is the facility they afford for correct and speedy reference to any particular part of the heavens. It is, therefore, customary among as- tronomers, when referring to the locality of a star, to say that it is in such and such a constellation. 51. The Milky Way. As a relief to the general deep blue which the sky presents, may be traced a whitish lustrous belt, 74 OL'l 'LINES OF AS TRONOM Y. arching the whole firmament, about eight degrees in breadth, and inclined at an angle of about sixty degrees to the ecliptic. This broad belt has been called the Milky Way, from its milk- white appearance. It passes in the northern hemisphere, between the horns of the Bull and the feet of the Twins ; and winds round, in the southern hemisphere, between the Archer and the Scorpion. Taking a hasty glance at it, nothing is perceived but a luminous haze, with here and there a star interspersed ; but on close observation it appears studded with small luminous points. The real nature of the Milky Way greatly puzzled the ancient philosophers, some ot whom imagined it was celestial fire beam- ing through the clefts of the solid universe. Modern researches have set the matter at rest by demonstrating, with the aid of . strong magnifying power, that it is composed of an innumerable host of individual stars. So thickly are they crowded together as to give the appearance of glittering dust. This star-dust, each grain of which, it must be remembered, is a separate and individual star, lies at an immeasurable distance. No mode of measurement hitherto adopted, can determine its remoteness. To give some idea of the distance of the stars composing the Milky Way, it may be stated that the distance of some of the fixed stars has been ascertained to be at least eighty billion (that is, eighty million million) miles; a space which light, the swiftest traveler with which we are acquainted, would occupy thirteen years in traversing, at a speed of 200,000 miles per second ; and that these stars are much nearer to us than those of the Milky Way. The brightest stars are at approximately measurable distances, but those in the Milky Way are at im- measurable distances. 52. The Nebula. Who that has looked out attentively at the clear blue sky, at night, has not observed a number of cloud-like patches of a rather faint or misty light. They form a pleasing contrast to the dark ground of the firmament, and appear as so many radiant spots, illuminated by some far distant bodies. These patches, which are of every variety of figure, and of different degree of intensity, have been named Nebulae, a word signifying clouds. Those which the telescope has succeeded in resolving, have been found to consist principally of clusters of U TUNE S OF AS TR ONOM Y. 75 countless stars, densely packed in the center, and gradually di- minishing in number towards the circumference of the nebulae. Besides the well-defined stars, a vast number of brilliant points have been observed interspersed, which, from their general ap- pearance, have also been termed light-mist. Great interest is manifested in the observation of these nebulae, in the present day. They were, for some time, supposed to consist of light vapory matter, and were regarded as embryo suns, or solar systems in a state of formation, This opinion is now nearly dispelled by the application of extraordinary telescopic power. Judging from what has been with certainty discovered, it is sup- posed that every speck of the light mist is a distinct star a solar luminary, the independent center of a number of worlds. What a vast conception of the universe does this idea present? How boundless appear the realms of space, when masses of matter so immense in size as those distant stars must be, are found so near to each other as to appear in contact, like grains of sand upon the sea shore, while the spaces between them must exceed, by thousands, if not millions of times, the actual bulk of each. And yet those which are included in our universe, with its myriads of suns, and attendant worlds, may be but a small portion of the wide creation of God. What lies beyond all that we can discern on every side, we, of course, cannot conceive. That what we at present witness, is all that exists, it would be presumptuous to affirm ; and much more so to assert that the inhabitants of our globe will ever behold all that exists in the wide extended range of creation. At most, we can enjoy but one aspect of the Creator's works, can view only that portion of the universe which is visible from the stand-point of our own orbital path round our own sun or star. We know that we are surrounded by "hosts" of sun-worlds the "hosts of heaven" that support still more numerous hosts of earth-worlds, but how far we are from even the nearest, the highest powers of astronomical science cannot reveal to us. We only know that they are all placed at such immense distances from us in the depths of space, that though we are 200 million miles nearer to some particular stars, at any given period of the year than we are six months later, not the slightest difference in the distance is discovered on 76 OU T LINES OF AS TRONOM Y. the application of the highest telescopic power we possess. We know that we are encircled by the Milky Zone, but we know not what is going on on the other side of it, and beyond that portion of the universe which lies within the range of our observation. Imagine for a moment that we were placed as far distant from the Milky Way, on its outside, as we are at present within, and what new views would be presented to our sight. \Ve might then discern as great a variety of new celestial objects, as far as the telescope-assisted eye could reach, as those with which we are familiar here. The thought is elevating, and should lead us upward to the contemplation of an Infinite Creator. In this department of his creation we have vividly presented us an i.v.age of his infinity and eternity. We recognize in his works a sphere of operations as boundless as Himself, the Source of all. In contemplating these effects of his omnipotence, we should view Him as a perpetual Creator. As a Creator he is infinite, and an infinite Creator cannot be other than a perpetual producer. There can be no cessation to his operations. The same almighty power which, in the beginning, produced one world, or system of worlds, is, doubtless, ever bringing forth more. An all-perfect Being is also an ever-active one. Let man humble himself before this great and good " Father of all" worlds and men, and receive with meekness those soul-elevating lessons which nature, in this her grandest aspect teaches, respecting the character and destiny of humanity. 53. In reference to the stellar orbs that compose the nebulae, we would ask, in the eloquent language of the late Dr. Chalmers, "Shall we say, of these vast luminaries, that they were created in vain. Were they called into existence for no other purpose than to throw a fide of useless splendor over the solitudes of immensity. Our sun is only one of those luminaries, and we know he has worlds in his train. Why should we strip the rest of these princely attendants. Why may not each of them be the center of his own system, and give light to his own worlds. It is true that we see them not ; but, could the eye of man take its flight into those distant regions, it would lose sight of our little world before it reached the outer limits of our system. the greater planets would disappear in their turn, and before it had OUTLINES OF ASTRONOMY. 77 descried a small portion of that abyss which separates us from the fixed stars, the sun would decline into a little spot, and all its splendid retinue of worlds be lost in the obscurity of distance-; he would at last shrink into a small invisible atom, and all that could be seen of this vast magnificent system, would be reduced to the glimmering of a little star. Why resist any longer the grand and interesting conclusion? Each of those stars may be the token of a system as vast and as splendid as the one which we inhabit. Worlds roll on in those distant regions, and these worlds must be the mansions of life and intelligence. In yon gilded canopy of heaven, we see the bro.id aspect of the universe, where each shining point presents us with a sun, and each sun with a system of worlds, where the Divinity reigns in all the grandeur of his attributes, where He peoples immensity with his wonders, and travels in the greatness of his strength through the dominions of one vast unlimited monarchy. The contemplation has no limits. If we ask the number of suns and of systems; the unassisted eye of man can take in a thousand, and the best telescope which the genius of man has constructed can take in 80 millions. But why subject the do- minions of the universe to the eye of man, or to the powers of his genius. Fancy may take its flight far beyond the ken of eye or of telescope. It may expatiate in the outer regions of all that is visible. And shall we have the boldness to say that there is nothing there? that the wonders of the Almighty are at an end because we can no longer trace his footsteps? that his omnip- otence is exhausted because human art can no longer follow Him ? that the creative energy of God has sunk into repose, because the imagination is enfeebled by the magnitude of its efforts, and can keep no longer on the wing through those misty tracks which shoot far beyond what eye hath seen, or the heart of man hath conceived, which sweep endlessly along, and merge into an awful and mysterious infinity ?" . THE END. >. UNIVERSITY of AT LOS ANGELES LIBRARY 4024 UNIVERSITY OF CALIFORNIA LIBRARY Los Angeles This book is DUE on the last date stamped below. Form L9-25m-9,'47(A5618)444 THE 1 T BBARY .IFORNU G9U