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ON THE PERPETUATION OF PLANTS. The essential protection which the calyx affords, THE care which the Creator has bestowed on the by enveloping everything while yet in a tender state, perpetuation of plants offers a wide field of inquiry. must not be forgotten; apt as we are to look on it as The collateral as well as the direct means of propa- a superfluous part, from attending only to the exgation are very numerous, and the results very ex-panded flower. It would be endless to point out the tensive and valuable.

The circumstance which is, perhaps, most striking in the mode of propagation by seeds, is the apparent anxiety for their production, in the means adopted. This is less sensible to common observation, where the magnitude, the duration, and the uses of the plant itself, are conspicuous; but it becomes striking in the smaller and more perishable ones, and is often very remarkable in the lowest parts of the scale. Thus in the oak, we pay little attention to the production of seeds; or if noting it, we still know that there is before us a being, destined to a life of so many centuries, that we scarcely think of its death, or of the necessity of a system of perpetuation.

numerous forms and modes under which it guards the unopened flower, and above all from the access of water. The calyx of the rose, so useless when expanded, is a familiar instance of protection afforded by a structure which, compared to the purpose, is very inartificial; and yet in this, and all similar forms, that protection is complete. In the cistus, possessing a flower of unusual tenderness and delicacy, a varnish is superadded, for the purpose of warding off the rains. The monophyllous calyces present a structure more apparently efficacious, yet the protection is not more complete. And if the scale calyces of the grasses offer a much simpler contrivance, the security which they afford is not the less perfect. The calyx of the poppy is lax, and not very firmly closed; but as a counterbalance to this, the flower bud is bent down by a curvature of the stem, and erects itself only when the protection of this deciduous guard is no longer wanted. The obstinacy with which this bud refuses to flower till it ean erect itself, belongs to a still more interesting circumstance in the physiology of plants: but under the present view, the inverted position enables the back of the calyx to ward off that water which might have penetrated the less perfect junction at the summit.

It is in the biennial and the annual plants that this anxiety for the continuation of the races is most obvious to common observation. Millions of individuals seem to be utterly worthless and there are even species without end, for which we can discover no use, though desirous to find at least an insect attached to each. Amid the hundreds of lichens and mosses, a very few would, as far as we can see, have fulfilled the purpose which they appear solely to serve, in producing soils on naked surfaces. Yet in these we trace the same care and the same anxiety. The annual seems to grow for no other purpose than to produce seeds; and that being accomplished, it That provision may here be pointed out in the dies. For this it struggles against every difficulty: liliaceous flowers, which, as a sheath, forms the suband under every check, every accident, every mutila-stitute for the absent calyx, while the leaves also are tion, it still labours for this end, as if it were a conscious agent. We cut off its flowers, or cut down itself, obstruet, impede it, in every manner, but it | still resists, proceeding with an obstinacy of determination to effect this great object; while if, tired of opposing it, we cease, it recommences, and having at length gained its purpose, dies. We can often even prolong the annual life for another year, or more, by the same opposition; as if it was determined not to part with existence till it had obeyed its orders and fulfilled its destiny.

The first mark of care, if a remote one, is found in the contrivances for protecting the future flower through the Winter, wherever such protection is necessary. In the buds, the beautiful packing, the investing scales, the down or hairs in some cases, and the varnish in others, are familiar: and, by these contrivances, aided by that vital power, the action of which in resisting cold has not been explained, the most complete protection is afforded. In the bulbous-rooted plants, the bud is not less effectually protected beneath the ground, partly by the depth of earth, and partly by the singular chemical properties of the coverings, aided by the same resisting vitality. In other cases, the flower bud is not produced till the frosts are passed; and our attention may now be directed to the provisions within it for the formation and ripening of the seeds. In a certain sense, indeed, the flower is a superfuity, an example of gratuitous beauty, while it also contains provisions for the feeding of insects; yet with these are always combined some uses for the seed itself, as, in many cases, they are so numerous and remarkable that they cannot be overlooked. The reader need only be reminded of the various ways in which they protect the essential parts of the fructification, the stamina, and the pistils, on which the future seed depends; and of the contrivances for bringing the pollen into contact with the latter.

sometimes arranged to perform the needful function. Under many different modes, the tulip, the genus Allium, the grasses, and far more, will afford examples of protection, given either to supply the want of a calyx, or to add to the security which that affords. And thus the seeds of the mosses are so embosomed in the plant, at first, as almost to elude the botanist; while they escape the chance of injury; to be elevated for dispersation, only when all hazard of failure is past.

sees.

It is under all this care and concealment, that the essential parts, destined to produce the perfect seed, are growing within; free from all hazard, till the expanding flower opens to the light that the work may be completed. And then do we begin to perceive the utility of many other preparations towards this great end, the purposes of which we might not have understood before, and which he who looks on this interesting part of creation with a common eye, never The vanity of philosophy may smile, if it pleases, at what it may choose to term fanaticism, but it is he who seeks for the hand of the Creator in every one of His works, who has found the true clue of investigation; since the purpose is that clue, and, that to study the design and the Designer, are one, And if the care of a parent for its offspring, the articipations, the preparations, the watchfulness of a mother, are objects of our admiration, shall we not at least investigate the contrivances, the thougat, the anxiety, of the Great Parent of all, for the safety and the life of these, His beautiful, but His lowest children; not inquire of his care for their perpetuit y, that not one shall be lost? Could more have been done; and if He has not done it, by whom then was it effected? Who is it that contrived, who is it that watches over the lilies of the field, that vot one of them should perish from his land? Who is it that g aards to maturity, even the minutest moss, and ens ares it a posterity, that it shall not fail from the multitude

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of His children, who, even in the vegetable world, |
look to Him for their food, their life, and their enjoy-
ment? Was it He: and is it He who cares not for
man, provides not for him, governs him not, watches
him not? Be it so, if it can afford satisfaction to
think that so it is: but it will not be so to him who
will open his eyes on the world around him, and who
has learned, in everything, to look to the Cause, the
Parent, of the universe. Would that I could per-
suade him who has hitherto walked through creation
without eyes, without thought, without a heart, to
take into his hand the first flower that shall present
itself, and examine it as the work of some Being at
least who intended, and wrought, and cared. If elo-
quence has long done its worst for this unfortunate
cause, there must be one who can sit down with the
next flower that meets him in his Summer walk, and
ask himself, Whence came this, why is it here, why
all this beauty, why all this care? I have seen it
rise from a minute seed, I trace a series of cares and
contrivances that seed shall spring from it again, I
trace these under a thousand forms, I marvel at their
ingenuity and their wisdom, I am astonished at an
anxiety which has neglected nothing, I see that an
end was intended, and I find that end attained.
What more does man ever do to attain his objects,
when does he labour with more care and more know-
ledge, and when does he succeed with more certainty?
Does woman show more anxiety, more contrivance,
for her offspring, than the Parent of this little flower
has displayed? And who can that careful, that
affectionate parent be? No one! Even so was it
no one that reared me from helplessness to maturity,
I knew no parent's thought, no mother's care: there
is no God. Can such a conclusion ever have entered
the heart of man? We know not how to believe him
who has declared it.

[Abridged from MACCULLOCH's Proofs and Illustrations
of the Attributes of God.]

THE CAMERA LUCIDA. THE Camera Lucida, an invention of Dr. Wollaston, like the Camera Obscura, is an instrument employed in making copies of drawings, and in portraying distant objects; but it is of greater service than the Camera Obscura, being much more portable, and, if properly used, reflecting the image of the object with

out the least distortion.

If a piece of thin glass is held at an angle of fortyive degrees with the horizon, at a small distance from the table, and a sheet of white paper is placed immediately beneath it, the reflected image of an object before it will be visible, by looking downwards upon it; and as the glass is transparent, the hand and pencil can also be seen, and an outline of the image can be made upon the paper. In this case the image is inverted. Such an instrument as this can be made off-hand very easily. Let в be a piece of thin plate-glass, about an inch and a quarter long, and three-quarters of an inch wide; A a piece of wood in which the glass is fixed, and c a piece of pasteboard with a small hole in it, forming an eye-piece to keep the eye directed to one point. Let this little instrument

be fixed on the top of a

Fig. 1.

small stand, and you have a Camera Lucida of the

simplest construction, but possessing the disadvantage of reflecting an inverted image.

Fig. 2.

But the inversion can be corrected by taking a little more pains. Let A be a piece of looking-glass fixed in a wooden or brass frame, and connected with a piece of clear glass, B, so that the angle C B A shall be an angle of one hundred and thirty-five degrees, the image of an object placed at F will be reflected from the look. ing-glass at A, and proceed to the clear glass at B: from this it will be reflected upwards to the eye at G, and the glass being transparent, the image and the hand will be seen at the same time; in this case the image is erect. But, in general, neither of these plans are resorted to, for in both cases, as there are two reflecting surfaces from the glass, there will ne cessarily be two reflected images, one of them certainly much less vivid than the other, but still suffi ciently visible to distract the eye

Fig. 3. A

B

The optical portion of the Camera Lucida which is usually sold consists of a prism. D Fig. 3 is a section of the prism employed; the angle A is equal to 224 degrees, c to 135 degrees, D 22 degrees, and в is a right angle of 90 degrees. The solid nature of the prism will not allow the hand to be seen through its thickness, and the instrument is used in a different manner to the last contrivance. A is the prism, в a moveable piece of brass, having a small eye-hole in it at в ; the reflected ray from c is received near to this corner of the prism, and reflected upwards to the eye; the eye-hole is so adjusted that one-half only is over the prism,

A

Fig. 4.

the other half leaves a free space through which the hand and pencil can be seen. In using the instrument a vast deal depends on the proper adjustment of this eye-hole.

If the light is very powerful on the object, and much less so on the paper, the part of the prism exposed through the hole should be small, and the opening through which the paper is seen large in proportion. On the other hand, if the light on the drawing is weak, a larger part of the prism must be uncovered. In copying a print, great care must be taken that the print itself is perfectly flat and per pendicular to the horizon, and that the side of the prism at B A, fig. 3, which is opposite the print, shall be parallel to it. If this is not attended to, the print will be thrown into perspective and the copy be distorted.

If the object is to be copied of its natural size, its distance from the prism in front must be equal to the distance from the eye to the paper; if it is to be reduced it must be placed at a greater distance; if to be enlarged, it must be brought nearer.

The Camera Lucida has been fixed to the eye-hole of a telescope or a microscope, in such a manner as to allow the objects within the field of vision to be copied on paper.

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LONDON:

JOHN WILLIAM PARKER, WEST STRAND. PUBLISHED IN WEEKLY NUMBERS, PRICE ONE PENNY, AND IN MONTHLY PARTS;

PRICE SIXPENCE.

Sold by all Booksellers and Newsvenders in the Kingdom.

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INTRODUCTION.

THE SOLAR SYSTEM.

"WHEN I consider thy heavens, the work of thy fingers; the moon and the stars, which thou hast ordained;-what is man, that thou art mindful of him? and the son of man, that thou visitest him?"-Psalm viii., 3, 4.

When the inspired Psalmist gave utterance to these words, he was evidently under the influence of those feelings of awe, wonder, and admiration, which are sure to be excited in every intelligent mind, by the splendid and sublime phenomena presented to us by the heavenly bodies. When we consider the magnitude and the number of those bodies, the immense distances which separate them one from another, the almost inconceivable velocity with which they move, and that those which we can see form, probably, but a very small part of the whole number;-when we revolve these things in our minds, we are naturally brought to reflect on our own insignificance in the grand scheme of creation. If a man, after having applied to himself the vain and self-satisfying appellation of "lord of the creation," were to remember that the glorious sun, and the planets which revolve around it, form but one particular division, class, or system in the universe,-that the earth is but an humble member of that system, and that he, man himself, is but a moving particle on the surface of this earth,-he may well be expected to give utterance to the sentiments of David, and to wonder how the Great Deity can regard with parental care so humble a member of so magnificent a whole.

But this feeling, as Addison has beautifully shown, arises from the narrow powers of our own minds. We know that our perceptive faculties soon reach a boundary beyond which we cannot pass: we study the laws of Optics, but We know not the nature of Light:-we feel that we live and think, but we know not what constitutes life and thought. When, therefore, we judge of the Great Creator, by our own standard, we are lost in wonder at the vastness and at the minuteness, as also at the countless number of the objects which are under the Divine protection. But when we consider God as an Omnipresent and Omniscient we then admit, indeed, that nothing is too vast, VOL. XII.

Being,

nothing too minute, nothing too numerous, for his notice; that He who could create and arrange the whole, can also watch over and preserve the minutest parts of that whole. Our notions of great and small are derived from our own imperfect experience, and strikingly show the limited scope of our minds. The distance of the sun from the earth is a quantity so immense, as almost to perplex the mind which reflects on it; and yet that distance is small, compared with the distance of the fixed stars :-again, the minuteness of the nerves and smaller blood-vessels of the human body, is such as to require the microscope to aid us in an examination of their structure, and yet there are other entire animals, endowed with life and powers of motion, which are so minute that the eye cannot perceive them. The words great and small, then, are for man's use; to the Almighty nothing is great, nothing is small; the revolving planet, and the animalcule whose world is a drop of water, being equally objects of his ever-active care. This divinelysustaining power of Him, in whom we live, and move, and have our being," is so obvious, that we may exclaim with the poet Thomson

Were every falt'ring tongue of man,
Almighty Father! silent in thy praise,

Thy Works themselves would raise a general voice,
E'en in the depth of solitary woods

By human foot untrod;-proclaim thy power,
And to the choir celestial Thee resound,

Th' eternal cause, support, and end, of all! Nothing is more calculated to elevate the mind, and to display to us the wonders of Creation, than the study of Astronomy. We propose, therefore, to place before our readers a popular view of the elements, which serve for the basis of the astronomer's study. In doing this, we need not have recourse to the mathematical reasonings on which the various statements of the astronomer are founded; but we shall confine ourselves to such a simple explanation of the Mechanism of the Heavens as may pave the way for the study of a more systematic treatise. We trust, therefore, that both those who have, and those who have not, an opportunity of referring to more elaborate works, will not find the following pages devoid of instruction.

369

GENERAL APPEARANCE OF THE HEAVENS.

LET us suppose a man to be totally ignorant of Astronomy, and to turn his attention from events occurring upon earth, to those which are presented by the heavens. He sees a brilliant and glowing body, the Sun, rise in the east, at from four to eight o'clock in the morning, (according to the season of the year.) This body gradually attains a considerable altitude in the heavens, and continues to rise until noon; it then gradually descends, and in its descent, bends towards the west, where it sinks, (apparently below the earth,) some time between four and eight o'clock in the afternoon. The spectator now loses sight of the glorious orb, which does not again become visible for several hours; and when it does again appear, it is not at the point where it escaped from view, but at the opposite side of the heavens, namely, at the point where it first appeared on the preceding day. On watching the progress of the sun, he finds that the path, before noticed, is again travelled over by the luminary, which becomes lost to his view, as before, in the west. A third and a fourth day the same phenomenon occurs; and the question naturally suggests itself to the observer's mind, "Is it the same cheering and dazzling visiter which I see day after day, or are they different bodies, resembling one another, and following one after another?" Were he to confine his attention to the occurrences of only a few days, he would, perhaps, think the latter supposition to be correct, viz., that they were different bodies which thus appeared to him day after day. But if he were to continue his observations for weeks, months, years, or the greater part of his life, and to find that the daily appearance of such a body still continued, he could hardly fail to conclude that it was the same body which thus so frequently attracted his attention and admiration. "But how?" (he might say,) "do I not see this ruddy disc of light dip into the ground in the west, and appear to me again in the east on the following morning: what becomes of it in the meanwhile?" To answer this question, or to obtain the means of answering it, he would, perhaps, trace more particularly the path which the sun followed from morning to evening, which he would find to be a semicircle, or a curve not differing much from it. If, likewise, he were to take note of the time occupied in these occurrences, he would soon find the time that the sun is above the surface of the earth to be, on an average, equal to the time that it is invisible.

From these two facts, it would be by no means unreasonable to arrive at the conclusion, that the sun moves in a circle; and that, while he is invisible to us, he is passing round the earth, in a direction from west to east, at which latter point he arrives at the moment that the observer sees him rise in the morning.

Here a difficulty arises, which it may well be supposed, would perplex the uninitiated observer. What can be meant by going round the earth, if the earth be, as it seems to our eyes, a flat and extended surface of ground, or water, which seems to touch the sky at the farthest points which the eye can reach :-how then can the sun pass round this? There can scarcely be a more reasonable question, so long as we judge merely by what meets the eye; but, if we extend our observations to certain appearances on the ocean, we begin to see proof that the surface of the water is not quite flat. On land, we have not the means of making a similar observation, because of the intervention of mountains and valleys. The proof that the surface of water is not quite flat, is derived from the following circumstance. If we are at sea, on a clear day, and watch the approach of a vessel from a distance, we find that the masts are visible sooner than the hull: we first see the top of the masts: then the whole height of the masts gradually comes into view; and finally, we see the hull. These different appearances of the ship, as it approaches towards the observer, are represented in the following figure. This could not occur if the earth were perfectly flat, because then the hull and masts would come into view at the same time.

It matters not what part of the world be chosen as the place of experiment; the result is almost exactly the same every where, and the amount of the bending of the surface of the ocean may be illustrated thus:-If we had a piece of string four miles long, and were to apply both ends to the surface of still water, and could possibly draw the string into a perfectly straight line, the middle of the string would be about sixteen inches below the surface of the water; thus showing that the water is not quite flat.

the earth is round, like a ball; a fact which was clearly Thus might be supposed to arise the first conjecture that proved by Captain Cook, who was the first to perform a voyage completely round the earth, about the year 1769. He left a given spot, and arrived again at that spot by an opposite course. from other sources, that the earth is a globe; but those will There is an abundance of proof, derived open upon us more plainly, as we advance. We have hitherto endeavoured to trace what would probably be the feelings and opinions of one who, without previous instruction in Astronomy, should note the appearances presented by the sun. But that golden orb is not seen to be a solitary inhabitant of the sky: another luminous body about as large in apparent size as the sun, would soon attract the notice of the gazer. He would see it rise in the east, soar aloft, and then sink in the west. After attain a height from which the lapse of a few hours it would again appear in the east,

....... With a boundless tide

Of silver radiance, trembling round the world,

it would again descend, to sink as before in the west. The train of reasoning which would lead the observer to conclude that the sun revolved round the earth, would lead him to a similar conclusion regarding the moon. But here the re semblance terminates. The sun always presents a perfect circle to the eye of the observer day after day, and month after month; but a few evenings suffice to show that such is not the case with the moon: at one time a crescent only is seen, whose hollow side is towards the left of the observer; at another time the hollow side is towards the right: the crescent sometimes enlarges to a perfect circle; and at others it contracts from a circle to a crescent. If, then, the moon be a ball or globular body, shedding light upon the earth, there is great difficulty in conceiving what can occasion the change in its apparent shape; but, if we were to consider the moon to be an opaque or non-luminous body, we should find the means of explaining the change in its apparent figure, by supposing that the sun shines upon the moon, and that it is only by the reflection of the sun's light from the moon that the moon becomes visible to us. If we place a large round ball on a table, in a place where the sun is shining, we shall see the ball more or less illuminated, according to our position with regard to the ball and the sun: in one position, the ball will appear to be equally divided by a boundary line, into two semicircles, one illuminated and the other in the shade: in another position, the illuminated portion will be only a crescent, all the rest being shaded: from another point again it will all appear illuminated, except a small crescent of shade. If the observer watch the relative positions of the sun and moon, he will see that the shape of the bright part of the moon depends on its relative position in respect of the sun; just as the bright portion of the illuminated ball depended the position in which he viewed it.

on

We should in this way find the means of accounting for the change in the shape of the moon. We shall, by and bye, show that these suppositions are really true. But another point would attract the notice of the observer, independently of the change in apparent form. If the two brilliant bodies, certain day when the latter appeared as a thin crescent to the sun and moon, were observed to be near each other on a the left of the sun, they would be seen the next day further removed, and on the following day, at a still greater distance from each other: if, therefore, the motion of the moon round the earth be admitted, it is necessary to suppose that motion to be slower than the sun's motion round the

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that the stars, like the sun and moon, revolve round the earth. But, by a careful attention to different stars, he would find that the same remark does not apply to all. Those which rise exactly in the east, set exactly in the west; those which rise to the south of east, set south of west; and many which rise somewhat north of east, set somewhat north of west; but in looking northward he sees stars which appear neither to rise nor to set, but which perform a complete circle round a particular point of the heavens. For example, there are seven stars, which, to most persons who pay any attention to the appearance of the heavens, are known under the name of the Great Bear. These stars never rise or set to an inhabitant of London. If they become invisible, it is either because clouds obscure them, or the superior brilliancy of the sun drowns their comparatively feeble light. The same may be said of five conspicuous stars known by the name of Cassiopeia's Chair.

If we watch the progress of these stars, and others in their vicinity, we shall find that they describe a circle round a star called the Pole-star. The position of this star we shall find to be nearly this: if we suppose the distance from the north point of our horizon (which is the line in which the surface of the earth appears to touch the sky) to the zenith (which is the point immediately over our heads) to be divided into five equal parts, then at about the height of three of those parts from the earth, will be seen the Pole

star.

All this would seem to show to an observer, that the Pole-star is the end of an axis round which all the stars revolve, and that the reason why we cannot see the whole circular path of any stars except of those in the vicinity of the Pole-star, is, that they pass round under the earth during a part of their journey, and are therefore concealed from our view. Those stars which are further removed from the Pole-star describe a larger circle than those which are nearer, while the Pole-star is almost stationary. This is exactly what takes place when we see a wheel turn round; the axle remains in one spot, but any particular point on the outer edge of the wheel describes a larger circle than that which is described by any point between the axle and the circumference.

If we consider the Pole-star to form one end of the axle or axis round which the stars revolve, then it is obvious that there must be an opposite end of the same axis, in the contrary direction. If then we turn towards the south, with the expectation of seeing such a point, we shall find that it will not be realized; for none of the stars in that quarter are seen to describe circles; for they all rise and set. Still, however, the semicircles or portions of semicircles, commonly called arcs, which they describe, appear to have a common centre, which is some distance below the horizon; and this centre may be considered as the southern end of the axis before spoken of.

If we suppose the observer to have arrived at this amount of information respecting the stars, he will be prepared to notice the uniformity of the positions of the stars with respect to one another. The Great Bear, for instance, whether it be under or over the Pole-star, or at the right or the left of it, will always have its seven principal stars at the same relative distances from each other. The changes which take place in the distance of the sun from the moon, would lead to the opinion that these revolve round the earth in unequal times; and by similar reasoning, the constant maintenance of the same distance between any two stars, would seem to imply that the stars revolve in equal times.

The seeming myriads of stars which present themselves to the notice of the observer all appear to follow this rule, of remaining at the same relative distances from one another, with very few exceptions. These exceptions, are, indeed, so few, that a constant watching of the same part of the heavens for a considerable period, would be necessary to determine that a star had actually changed its place relatively to other stars. There have, however, been discovered at different times ten stars, more or less brilliant, which change their relative distances from one another, and from other stars. These we know by the name of Planets; and by a careful attention to their movements, it is seen that each one travels in a curved path among the other stars, and returns again nearly to the point from whence it set out.

At intervals, again, star-like bodies of another order present themselves, whose progress among the other stars is more rapid than that of the planets; and which at a period more or less brief, vanish altogether from the view

of the observer, and do not return till after a long absence. To such bodies we give the name of Comets.

Such then are the equally sublime and facinating ap pearances which present themselves to the eye of an observer, when that eye is directed towards the heavens. That the invigorating and fructifying warmth and light shed by the sun,-the serene, quiet light of the moon,and the diamond-like glittering of the stars,-should invite men to a study of the laws which, under their Divine Creator, govern the motions of such exquisite globes of light, is what we are not only prepared to expect, but fancy that we should feel disappointment in finding it otherwise. Man is not, by nature, the cold heartless being who can let such beauties pass unheeded; and if he approach the study with the humility which true self-knowledge is calculated to engender, he becomes more and more able to appreciate the surpassing grandeur and power of the great Being who made and who rules all. Well, indeed, may we direct our attention to the phenomena which we have briefly described, and to which Milton so exquisitely alludes in the following lines:

First in his East the glorious lamp was seen,
Regent of day, and all th' horizon round
Invested with bright rays, jocund to run

His longitude through Heaven's high road; the gray
Dawn, and the Pleiades before him danced,
Shedding sweet influence: less bright the moon,
But opposite in levell'd West was set
His mirror, with full face borrowing her light
From him; for other light she needed none
In that aspect, and still that distance keeps
Till night; then in the East her turn she shines,
Revolved on Heaven's great axle, and her reign
With thousand lesser lights dividual holds,
With thousand thousand stars, that then appear'd
Spangling the hemisphere: then first adorn'd
With their bright luminaries that set and rose,
Glad evening and glad morn crown'd the fourth day.
Par. Lost, b. vii.

THEORIES TO EXPLAIN THE MOTIONS OF THE HEAVENLY

BODIES.

IN very early ages, before Europe occupied a page in the history of nations, the phenomena of the heavens were studied with great attention by several nations of the East. The Chaldeans, the Indians, the Chinese, and the Egyptians, have all left evidences of the industry and ingenuity with which their observations were conducted. They constructed observatories,-invented instruments for observing and measuring with accuracy,-separated the stars into different groups, called Constellations, for the facility of finding any particular star, gave particular names to most of the moving stars or planets, and noted the period which each took to move through its apparent path in the heavens; and, in many other ways, the ancients helped to lay the foundation of that mass of astronomical knowledge which the men of later ages have brought to more maturity.

Various opinions were formed respecting the motions of the sun, moon, and stars of all kinds, both with reference to one another, and also to the earth; but the first theory which had attained a name and an importance in the early ages of the world, was that of Ptolemy, a distinguished Egyptian astronomer, who lived about one hundred and thirty years after the birth of Christ. He conceived that the various bodies which had been distinguished by the appellation of "the heavenly host," were disposed in the order represented in the annexed diagram.

He supposed, according to the popular opinion, that the Earth was fixed as the centre of the universe, and that the Sun, Moon, Planets, and Stars, revolved round it in the following order; namely-the Moon, Mercury, Venus, Sun, Mars, Jupiter, and Saturn; the Moon being the nearest, and so on; exterior to all of which, he supposed that a great concave sphere in which all the stars were fixed, kept on revolving round the earth. From the early history of Astronomy, we learn that before the time of Ptolemy, it had been conjectured by some, that the earth passed round the sun, and not the sun round the earth; but the difficulty of believing a statement so contrary to appearances and to the evidence of one's physical senses, led to the rejection of this opinion; and although it was afterwards found to be

Seven small stars clustered together in the constellation Taurus. These stars rise with the sun about the time of Spring, and our poet, in this passage, intimates the old and common opinion that the Creation took place in the Spring.

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