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teration in the visible diameters of the more distant planets will be far less, seeing that the diameter of the earth's orbit bears an increasingly diminishing ratio to that of the orbit of each exterior planet in succession.

Let us recapitulate in a few words the various facts by which mathematicians have deduced the planetary distances. First, the diameter of the earth is determined by measurements taken on her surface, this serves as a basis for determining the sun's distance, from which are deduced the distances from him of all the other bodies of the system; with the distance of the sun thus known, and his angular diameter, his diameter in miles is easily calculated, and in like manner the diameter of a planet from the angle it subtends, and its distance at that epoch from the earth. As these angles are all very small, it will be readily seen that a minute error in the measurement would incur a large one in the resulting distance. The diameter gives the volume by the usual process of solid mensuration, and the power of the planet's attraction on its satellites if it has any, or on a neighbouring planet if it has not, will supply data for determining the amount of matter due to it, which, divided by the volume, gives its density. Thus, step by step, we arrive at one beautiful development after another; but not without mastering the profoundest branches of mathematical science, can any one determine all these for himself. The calculator in his study takes the result of observatorial labour, the observer works from formulæ supplied by abstract science, and by this division of labour has been built up the science of astronomy, which distances all others in its advance towards perfection.

We will now enter upon the consideration of the physical constitution of the members of the solar system, as far as we are likely to be safely conducted by the revelations of the telescope. We fear that our readers will be disappointed, when they learn to what a small amount our knowledge on this head will be reduced, if we throw aside all speculative reasoning and confine ourselves to bare facts. Mercury from his nearness to the sun, Neptune and Uranus from their immense distance, and the asteroids or planetoids from their minuteness, may be passed by as contributing nothing at all to the common stock of information, and we must be content with the results of the scrutiny of Venus, Mars, Jupiter, Saturn, and the sun; giving expression, at the same time, to the profound regret and unsatisfied longings with which we contemplate them, in despair of ever arriving at more certain conclusions on matters which, if known, would be of the highest interest.

From the examination of the spots on the sun, which constantly vary both in number and size, the conclusion is that he is surrounded by two atmospheres, an opaque underlying a luminous one: the removal of the upper discloses the dark atmosphere underneath, and the body of the sun, still more opaque, in the centre of the spot; in the spots generally the central portion is darker than that which surrounds it, and the two shades are definitely marked, not blended into one another.

As Venus is the planet which approaches the nearest of all to the earth, we might have hoped to have made out her features distinctly; but, as any one who has once had a telescopic view of her can bear witness, she is difficult of definition from the amount of light she reflects-she appears equally bright throughout the portion of her disk which is seen illuminated, and although her diurnal period is stated to be 24 hours nearly, the conclusion has been questioned by many observers; that she is surrounded by a dense atmosphere, is however an established fact.

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Mars in opposition has been watched attentively, and here a resemblance to our globe is undoubted. Messrs. Beer and Mädler, the selenographists, have actually produced a map of the planet, from twelve years' observations. The outlines of continents and seas, the former of a reddish tint and the latter green, have been well established; they are observed to retain the same form when they are visible, which is not always, hence we imagine them to be obscured by clouds floating in the atmosphere with which he is surrounded, just as our continents would be obscured to a Martial observer when crossed by a terrific storm. Near its poles brilliant white spots may be distinguished, which vary in size from time to time, at epochs, and in positions of the axis of the planet, which favour the conclusion that they are reflections from the ice and snow there accumulated during the winter, that as they melt by the returning heat of summer so they are found to diminish in size. A 3-feet telescope will satisfactorily show the polar spot, and a few of the features besides.

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Jupiter presents a magnificent view; accompanied by his four satellites, and streaked by his belts, he wraps the observer in delighted amazement. These belts are atmospheric, for they constantly vary in number and size, and not yet, probably, has any portion of his surface been laid bare to telescopic view; the rotation on his axis being performed in about 10 hours (as has been concluded by marking dark spots on the planet's disk), combined with his immense size, would, à priori, lead us to conclude that the centrifugal force at his equator, arising from the rapid rotation, would be very great. Observation confirms this supposition, for so visible is the difference between his polar and equatorial diameters, that it is easily recognized by the eye without measurement. The outline of the disk of Jupiter, seen through a telescope, is in fact an ellipse, whose two diameters

are in the ratio of 100 to 107. An illustration this of the prevalence of the same laws of gravitation on the planet which obtain on the earth.

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The drawing immediately following will serve to introduce the planet Saturn, which stands alone distinguished by the wonderful accompaniment of a series of rings (in addition to eight satellites), on which of late much labour has been spent in observation, seeing that they have been presented more directly to the earth than for many years past. What can possibly be the composition of these rings? What object do they serve? Here we are tantalized by a glimpse of another order of things, and speculations are aroused which will probably never arrive at the truth.

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The drawing will indicate two distinct bright rings, which may be reached by a five-feet telescope. The Rev. W. R. Dawes in England, and Professor Bond in Boston, simultaneously in 1850 recognized within the illumined rings another ring, not bright, but dark, which after observations showed to be partially transparent, for it allows, as it crosses, the body of the planet to be seen through it. Has this opaque ring always existed, or is it a recent production? It is impossible to say; but certain it is that during the past winter, as the writer can testify, it has been perceived through a five-feet telescope; and, had it existed before, could it possibly have escaped those telescopes, far more powerful, by which Saturn has been scrutinized during the last hundred years?

In comparing the conditions of the other planets with that appointed for our abode, we are struck with three peculiarities in which they essentially differ, and which must affect the provision made for animated beings, if

such exist on them.

1. The difference in the supply of light and heat they receive from the

sun.

2. The intensity of gravity on their surface.

3. The density of the materials of which they are composed.

A tabular view will show these peculiarities to advantage, earth being 1

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The effect of the first would be a necessity for optical organs and physical constitutions widely different from those of animated beings on our globe.

The second-namely, the difference in the force of gravity on the surface -would cause animals such as we are acquainted with to be crushed on the planet Jupiter by their own weight; while on Mars they would be able to spring double the height, with equal exertion, attainable on the earth.

The varying density of the planets indicates materials differing so much from the formations on our globe, that new laws and combinations must prevail to render them suitable to the wants of the inhabitants, to which they are, no doubt, as well adapted as is the earth to the support of the great human family. Mercury is of such a density as it would be were it composed of zinc throughout; the sun, Jupiter, and Uranus are the density of boxwood; Saturn and Neptune are such as they would be if composed of deal.

The conclusion to which observation has led us is, that the planets are subject, like the earth, to the laws of gravitation, which produce their motions, and confine bodies to their surface; that their satellites, like ours, are retained in their orbits by the same laws; and, analogically, we conclude that their purpose is to supply light during the absence of the sun. The laws of light extend to the planets; the alternation of the seasons takes place in several, of day and night in all. We perceive that several are surrounded with an atmosphere, but whether formed by the union of oxygen and nitrogen it is impossible to say. Speculations on the form and mode of being in those distant worlds are futile: that they are the abode of corporeal intelligences can hardly admit of a doubt in the minds of those who believe that the Almighty maker of the universe has created nothing in vain.

Notices of Books.

The Journal of Classical and Sacred Philology. No 1. (Cambridge: J. Deighton. Macmillan & Co. London: G. Bell).

THIS new work is an attempt, which we trust, for the sake as well as the credit of English scholarship, may prove a successful one, to re-establish a periodical of high literary pretensions, which shall be devoted to philological investigation in the most general sense. Following the footsteps, and commencing under the prestige of the too-little appreciated Cambridge Philological Museum and the Classical Museum, it has enlisted as contributors some of the best names among the resident University Graduates. And the opening number unquestionably gives proofs that the Universities contain critical scholars of a very high order. Perhaps, indeed, it is the persevering industry, rather than either the genius or the aptitude for research of the German School, which is wanting in this country. Origin

ality, if it exists, as we think it does, among us, is seldom shown to the same advantage as in German works, partly from the comparatively little encouragement it meets with, partly from so few of us having at command that astonishing parade of learning which our neighbours can always bring into the field of dissertation. In fact, philological literature has never greatly thriven among us; and we have some apprehensions for the future, unless a more generally interesting, not to say popular, character can be imparted to such works as the present. Of course very learned books are apt to be dull in proportion as they are difficult; and it behoves the editors to bear this in mind, and to enliven and simplify as far as is consistent with their undertaking.

The first paper is perhaps the most readable in the volume. It is a pleasantly and brilliantly written refutation of Süvern's well-known theory respecting the political under-plot or "moralis intelligentia," of the Birds of Aristophanes. We heartily agree with the conclusions of the writer, that such under-plot never existed till it was conceived in the fertile brain of the learned theorist; and we say this, not because the arguments here set forth against it are in themselves irresistible, which they appear to be, but because we had long ago arrived at the very same conclusion from much more general considerations. That play is probably the wittiest composition ever penned in any language; it is just such a play as the Greeks, with their intense appreciation of fun, would delight in. But it would have ceased to be fun, and become as grave' as a Lenten sermon, if every line and every name had contained some deep political allusion, which not one in ten thousand would have suspected, much less understood, on hearing it recited. "Süvern's general views," says the writer," have been received with unqualified assent, certainly without protest, by English scholars; and the book is still recommended to students about to read the Birds, as supplying the master-key to the poet's meaning." Yet the theory itself is proved to be so flimsy that it falls to pieces in every part, when a searching criticism is applied to its details. This is a singular example of that willingness to take almost anything at second hand from the Germans, which has long characterised our scholarship. We are so deficient in independent research, that we scarcely dare to impeach the authority of any one who bears the reputation of a philologist.

The second paper, on Lucretius, is clever and scholar-like; but, being purely a discussion of MSS. readings and verbal corruptions, it is too long to interest general readers, however valuable to those who are engaged in a critical perusal of this too-much neglected author, whom the writer is quite justified in calling "the greatest of extant Latin poets." We are not so sure that we agree with the last words of the following sentence: "He displays a wonderful depth and fervour of thought, expressed in language of singular force and beauty; an admirable faculty of clear and vigorous and well-sustained philosophical reasoning; and a style equal in its purity and correctness to that of Terence, Cæsar, or Cicero, and superior to that of any writer of the Augustan age." We must demur to placing the Latinity of Lucretius, which is often quaint and eccentric, before that of Horace and Virgil. The standard of "purity and correctness" is only arbitrary, and Lucretius was now and then forced to succumb to the metrical difficulty of his subject. Indeed, the writer himself allows him "such slight idiomatic deviations from strict grammar, as all Greek and Roman writers allowed themselves;" though we think this statement

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