contemplate drawings which show how the planet looks under telescopic scrutiny. This will at once appear when we consider that Saturn never lies at a less distance than 732,000,000 miles from the earth. With the most powerful telescope we see him no better (taking atmospheric effects into account) than we should if this distance were reduced to about a million miles. It is manifest that at this enormous distance all save the general features of his globe and of his rings must be indistinguishable. Where we seem to see a smooth, solid globe striped with belts, there may be an orb no part of which is solid,

girt round by masses of matter lying many miles above its seeming surface. Where we seem to see solid, flat rings, neatly divided one from the other either by dark spaces or by difference of tint, there may be no continuous rings at all; the apparent spaces may be no real gaps; the difference of tint may imply no difference of material. On these and other points, the known facts afford important evidence, and, by reasoning upon them, we are carried far beyond the results directly conveyed to us by telescopic researches.

Saturn is distinguished, in the first place, by the enormous range of his orbit, not merely in distance from the sun, but in the distances which separate it from the orbits of his neighbor planets. His mean distance from the sun is about 872,000,000 miles, his actual range of distance lying between 921,000,000 and 823,000,000. These figures are imposing, but they are, in fact, meaningless save by comparison with

other distances of the same class. Let it be noticed, then, that Saturn's mean distance from the sun exceeds the earth's more than nine and a half times. Now, Jupiter's distance exceeds the earth's rather more than five times (five and a fifth is very nearly the true proportion); so that between Jupiter's path and Saturn's there lies everywhere a span fully equal to four times the earth's distance from the sun. So much for Saturn's nearest neighbor on that side. But on the farthest side lies Uranus, more than nineteen times as far away from the sun as our earth is; so that between the paths of Saturn and Uranus there lies everywhere a span equal to Saturn's own distance from the sun. Now, all this is not intended as a mere display of wonderful distances. So far as mere dimensions are concerned, these arrays of figures are more imposing than impressive. But, so soon as we take into account the circumstance that a planet is in some sense ruler over the spaces through which its course carries it, those spaces being by no means tenantless, we see that, cæteris paribus, the dignity of a planet is enhanced by the extent of the space separating its orbit from the orbits of its neighbors on either side. Now, the space between the paths of Saturn and Jupiter exceeds the space inclosed by the earth's orbit no less than 63 times, while the space between the paths of Saturn and Uranus exceeds the space inclosed by the earth's orbit 270 times! Assuming (as we seem compelled to do by continually-growing evidence) that Saturn and his system were formed by the gathering in of matter from the region over which Saturn now bears sway, we cannot wonder that the planet is a giant, and his system wonderful in extent and complexity of structure. It is true that Jupiter on one side, and Uranus on the other, share Saturn's rule over the vast space, 330 times the whole space circled round by the earth, which lies between the orbits of his neighbor planets. But Saturn's rule is almost supreme over the greater part of that enormous space. Combining the vastness of the space with its position-not so near to the sun that solar influence can greatly interfere with Saturn's, nor so far away as to approach the relatively-barren outskirts of the solar system-we seem to find a sufficient explanation of Saturn's high position in the scheme of the planets as respects volume and mass, and his foremost position as respects the complexity of the system over which he bears sway.

Briefly, then, to indicate his proportions, and the dimensions of his system:

Saturn has a globe considerably flattened, his equatorial diameter being about 70,000 miles, while his polar axis is nearly 7,000 miles shorter. Thus in volume he exceeds the earth nearly 700 times, and all the four terrestrial planets-Mercury, Venus, the Earth, and Mars -taken together, more than 336 times. In mass he does not exceed the earth and these other smaller planets so enormously, because his density (regarding him as a whole) is much less than the earth's. In fact, his density is less than that of any other known body (comets,

of course, excepted) in the solar system. The reader is doubtless aware that the sun's mean density is almost exactly one-fourth of the earth's; Jupiter's is almost exactly the same as the sun's; but Saturn's is little more than half the sun's, being represented by the number 13 only, where 100 represents the earth's. Thus, instead of exceeding the earth nearly 700 times in mass, as he would if he were of the same density, he exceeds her but about 90 times. But this disproportion must still be regarded as enormous, especially when it is added that the combined mass of the four terrestrial planets amounts to little more than the forty-fourth part of Saturn's mass. The combined mass of Uranus and Neptune, though these are members of the family of major planets, falls short of one-third of Saturn's mass; yet, by comparison with Jupiter, whose mass exceeds his more than threefold, Saturn appears almost dwarfed. And it may be noted as a striking circumstance-one that is not sufficiently recognized in our astronomical treatises-that, while Jupiter's mass exceeds the combined mass of all the other planets (including Saturn) about two and a half times, Saturn exceeds all the remaining planets in mass about two and three-quarter times. So unequally is the material of the planetary system distributed.

The mighty globe of Saturn rotates on its axis in about nine hours and a half, the most rapid rotation in the solar system so far as is yet known.

But what shall we say to indicate adequately the dimensions of that enormous ring-system which circles around Saturn? Here we have no unit of comparison, and scarcely any mode of presenting the facts except the mere statement of numerical relations. Thus the full span of the rings, measured across the centre of the planet, amounts to 167,000 miles; the full breadth of the ring-system amounts to 35,600 miles. But these numbers convey only imperfect ideas. Perhaps the best way of indicating the enormous extent of the ring-system is to mention that circumnavigation of the world by a ship sailing from England to New Zealand by the Cape of Good Hope, and from New Zealand to England by Cape Horn, would have to be repeated 21 times to give a distance equaling the outer circumference of

the ring-system. The same double journey amounts in distance to but about two-thirds the breadth of the ring-system.

As to the scale on which Saturn's system of satellites is constructed, we shall merely remark that the span of the outermost satellite's orbit exceeds nearly twofold the complete span of the Jovian system of satellites, and exceeds the span of our moon's orbit nearly tenfold.

And now let us consider what is the probable nature of the vast orb which travels-girt round always by its mighty ring-system-at so enormous a distance from the sun that his disk has but the ninetieth part of the size of the solar disk we see. Have we in Saturn, as has been so long the ordinary teaching of astronomy, a world like our own, though larger-the abode of millions on millions of living creatures—or must we adopt a totally different view of the planet, regarding it as differing as much from our earth as our earth differs from the moon, or as Saturn and Jupiter differ from the sun?

We must confess that, if we set on one side altogether the ideas received from books on astronomy, endeavoring to view these questions independently of all preconceived opinions, it appears antecedently improbable that Saturn or Jupiter can resemble the earth either in attributes or purpose. We conceive that, if a being capable of traversing at will the interstellar spaces were to approach the neighborhood of our solar system, and to form his opinion respecting it from what he had observed in other parts of the sidereal universe, he would regard Jupiter and Saturn, the brother giants of our system, as resembling rather those companion orbs which are seen in the case of certain unequal double stars, than small dependent worlds like our earth and Venus. There are, perhaps, no instances known to our telescopists in which the disparity of light, as distinguished from real magnitude, is quite so great as that which exists in the case of the sun and the two chief planets of the solar system.' But we see in the heaven of the fixed stars all orders of disproportion between double stars, from the closest approach to equality down to such extreme inequality, that, while the larger star of the pair is one of the leading brilliants of the heavens, the smaller can only just be discerned with the largest telescopes yet made, used on the darkest and clearest nights. We have no

1 Even this is not certain. Jupiter, seen in full illumination from a stand-point so distant that both Jupiter and the sun might be regarded as equally distant from it, would appear to shine with rather more than the 3,000th part of the sun's light. This would correspond to the difference of apparent brightness between two stars of equal real magnitude and splendor, whereof one was about 54 times as far away as the other. There can be no doubt that the larger reflectors of the Herschels, Rosse, and Lassell, and the great refractors of Greenwich, Pulkowa, and Cambridge (United States), would bring the farther of two such stars into view if the nearer were of the first or second magnitude; and it is not at all unlikely that some of the exceedingly minute companions to bright stars, disclosed by these instruments, may be planets shining with reflected, not with inherent lustre.

reason to believe that the series stops just where our power of tracing it ceases; on the contrary, since the series is continuous as far as it goes, and since our own solar system is constituted as if it belonged to the series prolonged far beyond the limits which telescopic scrutiny has reached, we have reason for believing that such is indeed the interpretation of the observed facts. In other words, we may not unreasonably regard our solar system as a multiple system, a double star at certain ranges of distance, whence only the sun and Jupiter could be seen; a triple star at distances whence Saturn could be seen; and a quintuple star where Uranus and Neptune would come into view. To show what excellent reason exists for regarding Mercury, Venus, the Earth, and Mars, as not to be included in this view, it is only necessary to remark that not one of these planets could be seen until the limits of the solar system had been crossed. To eyesight such as ours, not one of the four terrestrial planets could be seen from Saturn, and still less, of course, from Uranus or Neptune. It would be as unreasonable to hold the ring of asteroids, or even the myriads of systems of meteorolites and aërolites, to be bodies resembling the earth and her fellow-terrestrial planets, as it is to hold these terrestrial planets to be bodies resembling Jupiter and his fellow-giants.

In all characteristics yet recognized by astronomers, Jupiter and Saturn differ most markedly from the earth and her fellow-planets. In bulk and mass they belong manifestly to a different order of created things; in density they differ more from the earth than the sun does; they rotate much more swiftly on their axes; they receive much less light and heat from the sun; the lengths of their year exceed the length of the earth's year as remarkably as their day falls short of hers; the atmospheric envelope of each is divided into variable belts, utterly unlike any thing existing in the earth's atmosphere; and, lastly, each is the centre of an important subsidiary scheme of bodies quite unlike the moon (the only secondary planet in the terrestrial family) as respects their relations to the primary around which they travel.

Notwithstanding all these circumstances in evidence of utter dissimilarity, and the fact that not one circumstance in the condition of the major planets suggests resemblance to the terrestrial planets, astronomy continues to treat of the planets of the solar system as though they formed a single family. It would appear as though the teachings of the astronomers who lived before the telescope was invented had so strong an inherent vitality, that more than two centuries and a half of discoveries adverse to those teachings are powerless to dispossess them of their authority. For no other reason can be suggested, as it appears to me, for the complete disregard with which the most striking characteristics of the major planets have been treated by modern astronomers.

If we consider one feature alone of those which have been just