Page images

269. Aquarius, or the Water Bearer, is represented by the figure of a man pouring out water from an urn, an emblem of the dreary and uncomfortable season of winter.

The last of the zodiacal constellations was Pisces, or a couple of fishes, tied back to back, representing the fishing season. The severity of winter is over; the flocks do not afford sustenance, but the seas and rivers are open and abound with fish.

"Thus monstrous forms, o'er heaven's nocturnal arch,
Seen by the sage, in pomp celestial march;
See Aries there his glittering bow unfold,
And raging Taurus toss his horns of gold;
With bended bow the sullen Archer lowers,

And there Aquarius comes with all his showers;
Lions and Centaurs, Gorgons, Hydras rise,
And gods and heroes blaze along the skies."

Whatever may have led to the adoption of these rude names at first, they are now retained to avoid confusion.

The early Greeks, however, displaced many of the Chaldean constellations, and substituted such images in their place as had a more special reference to their own history. The Romans also pursued the same course with regard to their history; and hence the contradictory accounts that have descended to later times.


270. Some, moreover, with a desire to divest the science of the stars of its pagan jargon and profanity, have been induced to alter both the names and figures of the constellations. doing this, they have committed the opposite fault; that of blending them with things sacred.

The venerable Bede," for example, instead of the profane names and figures of the twelve constellations of the Zodiac, substituted those of the twelve apostles. Julius Schillerius, following his example, completed the reformation in 1627, by giving Scripture names to all the constellations in the heavens.

Weigelius, too, a celebrated professor of mathematics in the University of Jena, made a new order of constellations, by converting the firmament into a cŒLUM HERALDICUM, in which he introduced the arms of all the princes of Europe. But astronomers, generally, never approved of these innovations; and for ourselves, we had as lief the sages and heroes of antiquity should continue to enjoy their fianced honors in the sky, as to see their places supplied by the princes of Europe.

271. The number of the old constellations, including those of the Zodiac, was only forty-eight. As men advanced in the knowledge of the stars, they discovered many, but chiefly in southern latitudes, which were not embraced in the old constellations, and hence arose that mixture of ancient and modern names which we meet with in modern catalogues.

272. Astronomers divide the heavens into three parts, called the Northern and Southern Hemispheres, and the Zodiac. In the

269. Of Aquarius and Pisces? Course of the Greeks and Romans, in displacing constellations? 270. What other reform attempted? What particular instances cited? Bede? Schillerius? Weigelius? How are these innovations regarded by astronomers? 871. Number of the old constellations? How others added? 272. How do astrono

northern hemisphere, astronomers usually reckon thirty-four constellations, in the Zodiac twelve, and in the southern hemisphere forty-seven; making in all ninety-three. Besides these, there are a few of inferior note, recently formed, which are not considered sufficiently important to be particularly described.

273. About the year 1603, John Bayer, a native of Germany, invented the convenient system of denoting the stars in each constellation by the letters of the Greek alphabet, applying to the largest star the first letter of the alphabet; to the next largest the second letter, and so on to the last. Where there are more stars in the constellation than there are Greek letters, the remainder are denoted by the letters of the Roman alphabet, and sometimes by figures.

By this system of notation, it is now as easy to refer to any particular star in the heavens, as to any particular house in a populous city, by its street and number. Before this practice was adopted, it was customary to denote the stars by referring them to their respective situations in the figure of the constellation to which they severally belonged, as the head, the arm, the foot, &c.

It is hardly necessary to remark that these figures, which are all very curiously depicted upon artificial globes and maps, are purely a fanciful invention-answering many convenient ends, however, for purposes of reference and classification, as they enable us to designate with facility any particular star, or cluster of stars; though these clusters very rarely, if ever, represent the real figures of the objects whose names they bear. And yet it is somewhat remarkable that the name of "Great Bear," for instance, should have been given to the very same constellation by a nation of American aborigines (the Iroquois), and by the most ancient Arabs of Asia, when there never had been any communication between them! Among other nations, also, between whom there exists no evidence of any intercourse, we find the Zodiac divided into the same number of constellations, and these distinguished by nearly the same names, representing the twelve months, or seasons of the year.

274. The constellations, or the uncouth figures by which they are represented, are a faithful picture of the ruder stages of civilization. They ascend to times of which no other record exists; and are destined to remain when all others shall be lost. Fragments of history, curious dates and documents relating to chronology, geography and languages, are here preserved in imperishable characters.

The adventures of the gods, and the inventions of men, the exploits of heroes, and the fancies of poets, are here spread out in the heavens, and perpetually celebrated before all nations. The Seven stars, and Orion, present themselves to us, as they appeared to Amos and Homer: as they appeared to Job, more than 3000 years ago, when the Almighty demanded of him-"Knowest thou the ordinances of heaven? Canst thou bind the sweet influences of the PLEIADES, or loose the bands of ORION? Canst thou bring forth MAZZAROTH in his season, or canst thou guide ARCTURUS with his sons?" Here, too, are consecrated the lyre of Orpheus and the ship of the Argonauts; and, in the same firmament, glitter the Mariner's Compass and the Telescope of Herschel.

mers divide the constellations? Number in each division? Total? What others? 278. John Bayer's invention? Utility of it? How before it was adopted? What remark respecting the figures on maps and globes, and their use? What remarkable facts stated? 274. Historical use of the constellations? Illustrations?



275. THE first conjecture in relation to the distance of the fixed stars is, that they are all placed at an equal distance from the observer, upon the visible surface of an immense concave vault, which rests upon the circular boundary of the world, and which we call the Firmament. We can, with the unassisted eye, form no estimate of their respective distances; nor has the telescope yet enabled us to arrive at any exact results on this subject, although it has revealed to us many millions of stars that are as far removed beyond those which are barely visible to the naked eye, as these are from us.

Viewed through the telescope, the heavens become quite another spectacle-not only to the understanding but to the senses. New worlds burst upon the sight, and old ones expand to a thousand times their former dimensions. Several of those little stars which but feebly twinkle on the unassisted eye, become immense globes, with land and water, mountains and valleys, encompassed by atmospheres, enlightened by moons, and diversified by day and night, summer and winter.

Beyond these are other suns, giving light and life to other systems, not a thousand, or two thousand merely, but multiplied without end, and ranged all around us, at immense distances from each other, attended by ten thousand times ten thousand worlds, all in rapid motion; yet calm, regular and harmonious-all space seems to be illuminated, and every particle of light a world.

276. It has been computed that one hundred millions of stars which cannot be discerned by the naked eye, are now visible through the telescope. And yet all this vast assemblage of suns and worlds may bear no greater proportion to what lies beyond the utmost boundaries of human vision, than a drop of water to the ocean; and, if stricken out of being, would be no more missed, to an eye that could take in the universe, than the fall of a single leaf from the forest.

We should therefore learn, says Dr. Chalmers, not to look on our earth as the universe of God, but as a single, insignificant atom of it; that it is only one of the many mansions which the Supreme Being has created for the accommodation of his worshipers; and that he may now be at work in regions more distant than geometry ever measured, creating worlds more manifold than numbers ever reckoned, displaying his goodness, and spreading over all the intimate visitations of his care.

277. The immense distance at which the nearest stars are known to be placed, proves that they are bodies of a prodigious size, not inferior to our sun, and that they shine, not by reflected rays, but by their own native light. It is therefore concluded,

275. What is the first conjecture as to the distance of the stars? Can we form no just estimate? What said of the heavens when seen through a telescope? 276. What computation as to the number of stars invisible to the naked eye, but visible through telescopes? Is this probably the whole universe? Remark of Chalmers? 277. What

with good reason, that every fixed star is a sun, no less spacious than ours, surrounded by a retinue of planetary worlds, which revolve around it as a center, and derive from it light and heat, and the agreeable vicissitudes of day and night.

These vast globes of light, then, could never have been designed merely to diversify the voids of infinite space, nor to shed a few glimmering rays on our far distant world, for the amusement of a few astronomers, who, but for the most powerful telescopes, had never seen the ten thousandth part of them. We may therefore rationally conclude, that wherever the All-wise Creator has exerted his creative power, there also he has placed intelligent beings to adore his goodness.

278. The greatest possible ingenuity and pains have been taken by astronomers to determine, at least, the approximate distance of the nearest fixed stars. If they have hitherto been unable to arrive at any satisfactory result, they have, at least, established a limit beyond which the stars must necessarily be placed. If they have failed to calculate their true distances from the earth, it is because they have not the requisite data. The solution of the problem, if they had the data, would not be more difficult than to compute the relative distances of the planets a thing which any schoolboy can do.

In estimating so great a distance as the nearest fixed star, it is necessary that we employ the longest measure which astronomy can use. Accordingly, we take the whole diameter of the earth's orbit, which, in round numbers, is 190 millions of miles, and endeavor, by a simple process in mathematics, to ascertain how many measures of this length are contained in the mighty interval which separates us from the stars.

The method of doing this can be explained to the apprehension of the pupil, if he does not shrink from the illustration, through an idle fear that it is beyond his capacity.

For example; suppose that, with an instrument constructed for the purpose, we should this night take the precise bearing or angular direction from us of some star in the northern hemisphere, and note it down with the most perfect exactness, and, having waited just six months, when the earth shall have arrived at the opposite point of its orbit, 190 millions of miles east of the place which we now occupy, we should then repeat our observation upon the same star, and see how much it had changed its position by our traveling so great a distance one side of it. Now, it is evident, that if it changes its apparent position at all, the quantity of the change will bear some proportion to the distance gone over; that is, the nearer the star, the greater the angle; and the more remote the star, the less the angle. It is to be observed, that the angle thus found, is called the star's Annual Parallax.

279. But it is found by the most eminent astronomers of the age, and the most perfect instruments ever made, that the parallax of the nearest stars does not exceed the four thousandth part of a degree, or a single second; so that, if the whole great orbit of the earth were lighted up into a globe of fire 600 millions of miles in circumference, it would be seen by the nearest star only as a twinkling atom; and to an observer placed at this distance,

proof that the stars are large bodies? What conclusion, therefore? What other inference? 278. What effort to determine the distances of the stars? What results? What necessary in estimating the distances of the stars? What measure taken? Describe the process of determining the distance of the stars by parallax. 279. What is the parallax of the stars found to be, and what follows as a consequence? What,

our sun, with its whole retinue of planetary worlds, would occupy a space scarcely exceeding the thickness of a spider's web.*

If the nearest of the fixed stars are placed at such inconceivable distances in the regions of space, with what line shall we measure the distance of those which are a thousand or a million of times as much farther from them, as these are from us?

280. If the annual parallax of a star were accurately known, it would be easy to compute its distance by the following rule : As the sine of the star's parallax:

Is to radius, or ninety degrees : :

So is the earth's distance from the sun :

To the star's distance from the sun.

If we allow the annual parallax of the nearest star to be 1′′, the calculation will be,

As 0.0000048481368-Nat. Sine of 1".

Is to 1.0000000000000=Nat. Sine of 90°.

So is 95,273,868.867748554=Earth's distance from the sun. To 19,651,627,683,449 Star's distance from the sun.

In this calculation we have supposed the earth to be placed at the mean distance of 84,047 of its own semi-diameters, or 95,273,868.867748554 miles from the sun, which makes the star's distance a very little less than twenty billions of miles. Dr. Herschel says that Sirius cannot be nearer than 100,000 times the diameter of the earth's orbit, or 19,007,788,800,000 of miles.

Biot, who either takes the earth's distance greater than he lays it down in his Traité Elementaire d'Astronomie Physique, or has made an error in figures, makes the distance 20,086,868,036,404. Dr. Brewster makes it 20,159,665,000,000 miles. A mean of these computations, is 20 billions; that is, 20 millions of millions of miles to a parallax

of 1".

Astronomers are generally agreed in the opinion that the annual parallax of the stars is less than 1', and consequently that the nearest of them is placed at a much greater distance from us, than these calculations make it. It was, however, announced in 1832, that M. d'Assas, a French astronomer, had satisfactorily established the annual parallax of Keid (a small star 8° N. of Gamma Eridani), to be 2", that of Rigel, in Orion, to be 1.43, and that of Sirius to be 1".24. If these results could be relied on, Keid would be but 10 billions, Rigel but 14 billions, and Sirius 16 billions of miles from the earth. This latter distance is, however, so great that, if Sirius were to fall toward the earth at the rate of a million of miles a day, it would take it forty-three thousand, three hundred years to reach the earth; or, if the Almighty were now to blot it out of the heavens, its brilliance would continue undiminished in our hemisphere for the space of three years to come.

* A just idea of the import of this term, will impart a force and sublimity to an expression of St. James, which no power of words could improve. It is said, chapter i. verse 17, of Him from whom cometh down every good and perfect gift, that there is " ουκ ενι παραλλαγη η τροπης αποσκιασμα.” Literally, there is “ neither paraliam nor shadow of change:" As if the apostle had said-Peradventure, that in traveling millions and millions of miles through the regions of immensity, there may be a sensible parallax to some of the fixed stars; yet, as to the Father of Lights, view him from whatever point of his empire we may, he is without parallax or shadow of change!

then, of the more distant stars? 280. How deduce the distance of a star from its parallax, if known? Computation laid down? Dr. Herschel's remark? Biot's estimate? Dr. Brewster's? The mean of these three estimates? Are astronomers agreed as to the parallax of the stars? M. d'Assas' computations and results?

« PreviousContinue »