Fig. 37.

round their common centre of gravity which will be the centre of the circle. From the centre of the circle, draw a line perpendicular to the plane of their orbit, extending to equal distances

and b, (fig. 37,) moving in a circular orbit apply to the almighty architect the language of the sacred writer-"How unsearchable are thine operations and thy ways past finding out!" When we consider that around each of these moving suns a retinue of planets must be supposed to wheel their courses, at different distances and in different periods of time, we cannot but feel astonished at the complexity of motions, perturbations, and other effects which must necessarily follow; yet we are bound to believe that every thing moves onward, not only without confusion, but in the most perfect order and harmony, for He who at first arranged the plan of the material world, and impressed upon matter the laws which now operate, is possessed of boundless intelligence, and foresees at one glance all the effects which those laws can possibly produce; and, so far as our observation extends, every object and movement in nature appears to be adjusted with the most perfect regularity.

a

bove and be low this centre. Let us now suppose a third star, c, to fall from one extremity of this perpendicular, from a state of rest; it will obviously descend with a gradually accelerated motion till it reaches the centre of gravity; and passing onwards with a motion gradually retarded, it will move to the other end of the perpendicular, where it will arrive at a state of rest, and again return and continue to oscillate between these two points. The two stars which move in a circular orbit may describe equal ellipses of any degree of eccentricity. In this case, how ever, the perturbations will affect not only the planes of their orbits, but also their figures; and the length of the oscillations of the third will be sometimes increased and diminished.

A sun oscillating in a line perpendicular to the orbit of other two suns, and continuing its motion for ages in that line, is certainly a very strange idea; and yet, from the variety we perceive in the arrangements of the universe, it is not at all improbable that such combinations may exist among treble stars. The idea here intended to be conveyed may be illustrated by suspending a ring, and placing a wire perpendicular to it in its centre. The ring will represent the plane of the orbit in which the two equal stars move, and the perpendicular wire the line or course of the third star moving backward and forward with different degrees of accelerated and retarded motion. The motions connected with quintuple and multiple stars must be still more complex than those to which we have adverted; but it is difficult in the mean time to form any distinct ideas on the subject, till actual observation in the course of succeeding ages shall pave the way for deducing definite conclusions. The discoveries already made open to view new scenes of celestial mechanisin, and new views of the diversified and admirable contrivances of Divine Wisdom, so that, in reference to such objects, we may

The solution of the "problem of three bodies" was considered as a work of so great nicety and difficulty that none but such profound mathematicians as Clairaut, D'Alembert, and Euler, could undertake such a delicate and laborious investigation. This problem was, "to determine the curves described by three bodies projected from three points given in position, and with velocities given in quantity and direction-the force with which they gravitate being directly as their quanti ties of matter, and inversely as the squares of their distance." If the resolution of such a problem required so great acuteness of intellect, and so eminent skill in the science of analysis, what perspicacity of intellect, and what profound knowledge of every thing connected with physical and mathematical investigations must be requisite to determine the courses described and the perturbations produced by the complex motions of five, six, or seven suns all connected together, yet moving in different curves and in different directions, along with hundreds of planets, cach connected with its own sun and pursuing its own distinct course, yet acted upon in succession with different degrees of force by the attractive influence of other suns! boasted powers of analysis are completely incompetent for such determinations. The faculties of an archangel, or of intelligences of a higher order than that of man, are alone adequate to such investigations; and this circumstance affords a presumptive evidence that such superior intelligences actually exist in the universe, and that man, in the present improvement of his powers, may be in the act of training for the employments and the society of such intellectual beings in a future scene of existence.

All our

6, or 41 Orion, the small telescopic trapezium in the nebula. Right ascension, 5 26'; south dec., 5° 37′. The stars composing this quadruple star are considerably unequal. The most southern star of the following side of the trapezium is the largest; and the star in the opposite corner is the smallest, the other two being nearly equal. The largest is pale red; the star preceding the largest inclined to garnet; and the star opposite the A large star 1° preceding towards 41 of largest dusky. Distance of the two stars in the Swan. The two nearest are extremely the preceding side, 8 seconds; in the southern unequal. The largest is white, and the side, 124 seconds; in the following side, 15 smallest pale red. Their distance with 460 seconds; and in the northern side, 20 seconds. is 2 diameters of the largest. The third and The first star (in right ascension) is of the the largest are extremely unequal, and belong seventh magnitude, the second of the eighth to the fifth or sixth class. magnitude, the third of the fifth magnitude, and the fourth of the sixth or seventh magni

equal, and both red. Distance, 29". In the preceding one consists are considerably the sextuple or south following set, the two unequal. The largest of these is larger than largest are pretty unequal, and both red. the single star, and the least of the two is less Their distance is 19.-The other stars are than the single star. The first and second as small as the smallest of the quadruple set. largest and pretty unequal, and the second and 3° north preceding H Gemini, (of the fifth third pretty unequal. The two nearest are magnitude,) in a line parallel to the 65 Orion, pale red. They are just separated with a (in the club, and of the fifth magnitude,) and power of 278, and with 460 their distance is ? Taurus, the middle of the three. The stars in this quintuple star are in the form of a cross. The two nearest, or the preceding of the five, are extremely unequal. Distance 20. There is a very obscure star of the third class near the last of the three, in the obscure star of the cross. Other five stars are dispersed

about the quintuple one.

Between 3 and Dolphin, but nearer to 3 All the three stars are whitish red, and nearly equal. Distance of the two nearest with a power of 278, 21".

Near 27 Cepheus, near S. The distance of the two nearest of this treble star is about 20′′. 3, or 10 Lyru, (of the third magnitude, and about 70 south-east of the bright star Vega.) The stars of this quadruple star are all white, the secon. 1, third, and fourth, inclining to red. The first and second are consider ably unequal; the first and third very unequal; and the first and fourth unequal. Distance of the first and second, 44′′.

B, or 78 Gemini, (Pollu v.) The stars of this multiple star are extremely unequal. The nearest distance is 1' 57"; the next distance is 3′ 17′′.

In the Unicorn's head. This multiple star consists of one star with about twelve around it. 16° west of Procyon.

3, or 16 Cancer. This very minute treble star requires very favourable circumstances to ne distinctly seen. The two stars of which

the diameter of the smaller one. Zeta Cancri is situated about 12 or 13 degrees south-east of Pollux, nearly in a line parallel to that which joins Castor and Pollux, and nearly the same distance north by east from Procyon. It appears as a star of the fifth or sixth magnitude, and is sometimes distinguished by the name Tegmine. As a double star it is easily distinguished by a power of 140, with a 3 feet achromatic telescope, whose aperture is 23 inches, and might perhaps be seen with a power of 100. But it requires a much higher power to distinguish it as a treble star.

Most of the above stars may be found by consulting large planispheres of the heavens, or a common celestial globe. To facilitate the finding out of their positions, I have inserted in the above list some special directions, which may perhaps be of use to the astronomical tyro who is furnished with a moderately good telescope. It is to be regretted that, even on some of our latest 18-inch celestial globes, several of the stars above referred to are not distinctly marked, either with their number or with the Greek letters by which they are generally distinguished, and some of them are altogether omitted; such, for instance, as the celebrated star 61 Cygni, which is a double star, and whose proper motion is greater than that of any other star yet dis covered in the heavens.

CHAPTER X
On the Milky Way.

As we advance in our survey of the distant regions of the universe, the astonishing grandeur and extent of the sidereal heavens gradually opens to our view. We have hitherto considered only a few objects on the outskirts of the heavens, in respect to their distance, magnitude, and the wonderful complication of systematic motions which prevails among them. Had we no other objects to engage our attention, ages might be spent in contemplating and admiring the economy and magnificence of those starry groups which appear to the unaided eye on the nearer boundary of our firmament. But all this is visible to man's unassisted vision is as nothing when

compared with the immensity of august and splendid objects which stretch themselves in boundless perspective towards infinity. The discoveries of modern astronomy have enlarged the sphere of our conceptions far beyond what could formerly have been surmised, and opened to view a universe boundless as its Creator, where human imagination is lost and confounded, and in which man appears like a mere microscopic animalculum, and his whole habitation as a particle of vapour when compared to the ocean. In contemplating the visible firmament with the unassisted eye, we behold only the mere portals, as it were, which lead to the interior recesses of the vast

ter of the heavens, at the head of Cepheus, or about 30° from the north pole, we may trace it through Cassiopeia, Perseus, Auriga, part of Orion, and the feet of Gemini. At this last point it crosses the Zodiac, and proceeding southward across the equinoctial into the southern hemisphere, it passes through the Unicorn and the middle of the ship Argo, where it is most luminous. It then passes through Charles's Oak, the feet of the Centaur, the Cross, the Altar, the tail of Scorpio, the bow of Sagittarius, and a part of Ophiuchus. Here it separates into two branches as it passes again over the Zodiac into the northern hemisphere. One branch runs through the tail of Scorpio, the bow of Sagittarius, the shield of Sobieski, the feet of Antinous, Aquila, Delphinus, the Arrow, and the Swan. The other branch passes through the upper part of the tail of Scorpio, the side of Serpentarius, Taurus Poniatowski, the Goose, and the neck of the Swan, where it again unites with the other branch, and passes on to the head of Cepheus, the place of its beginning. After sending off the two branches above mentioned, they unite again after remaining separate for the space of more than 100 degrees. There is another small separation of the Milky Stream between Cassiopeia and Perseus. streams appear to leave a blank about the head of Perseus, and a considerable space on each side of it, to the extent of about thirty degrees in length, and three in breadth, and are again joined into one stream in the sword of Perseus, adjacent to Cassiopeia.*

Temple of Creation. When we direct our This zone may be traced in the heavens as views beyond these outer portals, by means of follows:-Beginning near the northern quarthe most powerful telescopes, we obtain a view of some of its more magnificent porches, and a faint glimpse of those splendid apartments which we shall never be able to explore, but which lead us to form the most august conceptions of the extent and grandeur of what is concealed from our view. In entering this Temple "not made with hands," the splendour of its decorations, the amplitude of its scale, and the awfulness of infinitude, forcibly strike the imagination. There is sufficient to awaken into exercise all the powers and feelings of devotion, and to excite us to fall down into humility and adoration before Him whose word spoke into existence this astonishing fabric, and "whose kingdom ruleth over all." These reflections may not appear altogether unappropriate when entering on a description of the Milky Way, which contains objects calculated to excite our highest admiration. When we take a general view of the heavens about the months of August, September, and October, and during the winter months, we cannot fail observing a large, irregular, whitish zone stretching across the sky, with a few interruptions, from one end of the firmament to another. This mighty zone, thus stretching itself around us, is sometimes termed the galaxy, sometimes the Via Lactea, but more frequently, in plain English, the Milky Way, from its resemblance to the whiteness of milk. This luminous band is visible to every observer, and is the only real and sensible circle in the heavens. When traced throughout its different directions, it is found to encircle the whole sphere of the heavens, though in some parts of its course it is broader and more brilliant than in others It forms nearly a great circle of the sphere, but it coincides neither with our equator, ecliptic, nor colures, nor with any other artificial circles which we conceive as drawn around the firmament. In all ages, so far as we know, this wonderful zone has retained the same position among the constellations as at the present day, and is frequently alluded to both by the astronomers and the poets of antiquity. Thus Ovid, on account of its lustre, represents it as the high road to heaven, or the court of Jupiter:

The two

From the above description it will appear that the form, breadth, and general appearance of this zone are various in different parts of its circuit round the heavens. In some places it appears dense and luminous, in others faint and scattered; in certain points it appears broad, and in others narrow. Its breadth in some places, as between Auriga and Perseus, is only about four or five degrees; in other places, as in the southern parts of Scorpio, Ara, and the Cross, its breadth is from ten to fifteen or eighteen degrees. It assumes the appearance of a double path from the tail of the Scorpion, through the bow of Sagittarius, Antinous, Aquila, Taurus Poniatowski, the Goose, and part of the Swan. It is more or less visible at every season of the year; but in Britain and in other northern latitudes it is most conspicuous during the months part of July, and the beginning of November. of August, September, and October, the latter About the middle of August, at nine o'clock in the evening, it may be seen stretching in an

* See the direction of this zone in the map of the stars on Mercator's projection.

12

ɔblique direction over the heavens, from northeast to south-west, and its apparent motion along the heavens may be traced along with that of the other constellations. At other seasons of the year, and at other hours of the night, its position and form will appear somewhat different. It appears most brilliant in the southern hemisphere, particularly in the neighbourhood of Argo, Ara, and the splendid constellation of the Cross. Between the tropics, where the atmosphere is clear and serene, it appears most vivid and brilliant. Mr. Brydon informs us that, from the top of Etna, it appeared "like a pure flame that shot across the heavens."

and other firmaments rising to view, whose distances baffle the utmost stretch of imagination.

"O what a confluence of ethereal fire
From suns unnumbered down the steep of heaven
Streams to a point and centres on my sight."

The following contains a brief summary of Sir W. Herschel's observations on this region of the heavens, made with a Newtonian reflecting telescope of twenty feet focal length and an aperture of eighteen inches. He found that this instrument completely resolved all the whitish appearances into stars, which the telescopes he formerly used had not light enough to do. The portion he first observed was that about the hand and club of Orion, and he found in this space an astonishing number of stars, whose number he endeavoured to estimate by counting many fields; that is, the apparent space in the heavens he could see at once through his telescope, and computing from a mean of these how many may be contained in a given portion of the milky way. In the most vacant place to be met with in that neighbourhood he found 63 stars; other six fields contained 110, 60, 70, 90, 70, and 74 stars, a mean of all which gave 79 for the number of stars to each field; and then he found that, by allowing fifteen mi nutes for the diameter of his field of view, a belt of fifteen degrees long and two broad, which he had often seen pass through his telescope in an hour's time, could not contain less than 50,000 stars, large enough to be distinctly numbered; besides which he suspected twice as many more, which could be seen only now and then, by faint glimpses, for want of sufficient light. The reader may acquire some conceptions of this immense number of stars occupying so small a space, if he consider that it is fifty times more than all the stars which the naked eye can discern at one time throughout the whole heavens, and that the space they occupy is only the

The ancients seem to have conjectured that the whiteness of this zone was owing to a confluence of stars; for Ovid, in the lines above quoted, says, "Its groundwork is of stars." Soon after the invention of the telescope this conjecture was confirmed, and astronomers were astonished at the number of stars which appeared in this bright zone of the heavens; and their number appeared to be increased in proportion to the magnifying powers of their telescopes. But it was not before Sir W. Herschel applied his powerful instruments to this region of the heavens that its profundites were explored, and all its minute nebulous parts shown to consist of countless myraids of stars, of every apparent magnitude, stretching onward to the regions of infinity, till they appeared to be lost to the view, even when assisted by the largest telescopes. On first presenting telescopes of considerable power to this splendid zone, we are lost in amazement at the number, the variety, and the beautiful configurations of the stars of which it is composed. In certain parts of it every slight motion of the telescope presents new groups and new configurations, and the new and wondrous scene is continued over a space of many degrees in succession. In several fields of view, occupying a space not much more than twice the breadth of the moon, you perceive more of these twinklingth part of the visible canopy of the healuminaries than all the stars visible to the naked eye throughout the whole canopy of heaven. You seem to penetrate, as it were, to the remoter bounderies of creation, and feel bewildered and lost amidst the immensity of the universe. I have never been inspired with higher ideas of grandeur and sublimity, nor felt deeper emotions of humility and revcrence, than when occasionally contemplating this stupendous scene through telescopes of considerable brilliancy and power. There is not another scene in creation, open to the view of mortals, calculated to fill the soul with more august conceptions, or to inspire it with more profound admiration and awe. In such surveys we behold "new heavens"

vens; so that if every part of the firmament were equally rich in stars, there would be within the reach of such a telescope as Herschel's no less than 68,750,000, or sixty-eight millions, seven hundred and fifty thousand stars. And we are further to consider that it was only in the comparatively "vacant places" of this zone that the number of stars above stated were perceived.

In some of his observations of other parts of this zone, Sir W. Herschel informs us that he descried a much greater number of these "Im luminaries in a similar extent of space. the most crowded parts of the Milky Way," he says, "I have had fields of view that contained no fewer than 588 stars, and these