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And yet degraded past the meanest slave.
Such tricks doth fickle Fortune interpose
Between the infant's cradle and the grave.
The Flower of Florence' blasted with the wind
Of sad misfortune! She around whose path
The angels seemed to walk and bring her joy:
She whose rich dowry far outshone the wealth
Of many kings; she who espoused the arts,
With Malesherbes took counsel, and who urged
The matchless Rubens on to excellence :
She who endowed a convent for the poor,
Yet had no pillow for her aching head:
Who built the palace of the Luxemburg,
And in a hovel died despised and spurned.

The mystery of suffering is here;

One is to pleasure, one to anguish born,
And who decides the share of happiness?

Yet will we mourn with those who aye must weep,
And trust, as we would trust for this great Queen,
That though the elements may dash their bark
Upon the rocks, and deeps upon them gape,
Some broken spar may bear them safe to land.

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THE EVER-WIDENING WORLD OF STARS.
BY RICHARD A. PROCTOR, B.A. F.R.A.S.,

Author of Saturn and its System,' &c. &c.
against the new theory.

S the science of astronomy has

6

formed respecting the extent of the universe have gradually become more and more enlarged. In far-off times, when astronomers were content to judge of the conformation of the universe by the appearances directly presented to their contemplation, the ideas formed respecting the celestial bodies were singularly homely. We read that Theophrastus looked upon the Milky Way as the fastening of the stellar hemispheres, which are so carelessly knitted together, that the fiery heavens beyond them can be seen through the spaces.' Anaximenes believed the heavens to be made of a kind of fine earthenware, and that the stars are the heads of nails driven through the domed vault formed of this material. And even Lucretius, whose views of nature were so noble, has referred without disapproval to the bizarre theory of Xenophanes that the stars are fiery clouds collected in the upper regions of air.

While the Ptolemaic system of astronomy was accepted there were no means of forming any trustworthy views respecting the extent of the stellar universe. If the earth were ever at rest we could never know how far the stars are from us; and therefore the old astronomers were free to invent whatever theories they pleased as to the scale on which the sidereal scheme is constructed. It was only when the earth was set free by Copernicus from the imaginary chains which had been conceived as holding it in the centre of the universe that it became possible to form any conception of the distances at which the stars lie from us. Indeed Tycho Brahé immediately pointed this out as an overwhelming objection

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Are we to

that the stars

are placed at such enormous distances from us as to seem wholly unchanged in position while the earth sweeps round the sun in an orbit millions of miles in diameter? If this amazing theory were true, the stars would be hundreds of millions of miles from us, a view which is utterly monstrous and incredible.'

But strange as this new view appeared, it gradually gained ground. It became presently so well established that when Cassini discovered that the earth travels in a much wider orbit than Tycho Brahé had supposed-so that the stars were at once thrown many hundreds of millions of miles farther from usastronomers still held to the new order of things. 'With Briarean arms,' as Humboldt has described their labours, the fellow-workers of Cassini thrust farther and farther away the 'heaven of the fixed stars,' until the immensity of the universe grew so great beneath their labours, that new modes of expressing its dimensions had to be adopted. They were not satisfied with the obvious circumstance that the stars seem to remain unchanged in position as the earth sweeps round the sun. They tested this apparent fixity of position with instruments of greater and greater power, yet always with the same result. They made obversations ten, twenty, even fifty times more exact than Tycho Brahé's, and the fact that they still detected no change of position signified nothing less than that the universe of the fixed stars is ten, twenty, even fifty times farther from us than Tycho Brahé had imagined.

Thus when Sir W. Herschel began the noble series of researches amid the stellar depths which has

rendered his name illustrious, the world of stars was already one of inconceivably enormous extent. Yet so widely did he increase our appreciation of the vastness of the universe, that it has been thought no exaggeration to say of him, that he broke through the barriers of the heavens.' 'Cælorum perrupit claustra,' says his monument at Upton, and every student of astronomy who has carefully examined Herschel's labours, understands the justice of the expression. For consider what Herschel did. When he began his survey of the heavens, astronomers had proved indeed that the nearest of the fixed stars lie at enormous distances from us, and some of the more advanced thinkers had begun to form noble speculations respecting the relations of the stars which lie beyond the sphere of those visible to us. But

it was reserved for Sir W. Herschel to apply exact observations to the unseen star-systems. He literally gauged the celestial depths. With a telescope whose light-gathering power probably extended the range of vision to about eight hundred times its natural limit, he swept every part of the northern heavens. He estimated the depth of the system of stars in every direction by a simple and natural process. For, like all great thinkers, he struck out modes of inquiry which, the moment they were presented to the world, seemed so obvious, that the wonder was how they could have remained so long undetected. He said that precisely as the quantity of water passed through by the sailor's lead-line marks the depth of the sea, so the number of stars which can be seen when a telescope of given power is turned towards any part of the heavens is a measure of the depth of the sidereal system in that direction. In individual cases, indeed, the law may not be true, just as the sailor's lead-line may light on the peak of some sunken rock, and so give no true

measure of the general depth of the sea in the neighbourhood. But when the average of a great number of such 'star-gaugings' is taken, then we may feel tolerably certain that on applying the simple rule devised by Herschel we shall form no inaccurate estimates of our system's extent in any direction.

Thence arose his great theory of the stellar system. He showed that our sun is but one of an immense number of suns, distributed in a region of space resembling a cloven disc in figure. When we look along the thickness of the disc we see the enormous beds of stars, which lie round us in that direction as a cloud of milky light, which so comes to form a cloven ring round the heavens. But when we look out towards the sides of the disc, where the stars are less profusely scattered, we see between them the black background of the sky.

Then Herschel extended his researches to those strange objects called the nebula. He showed that where astronomers had reckoned tens of these objects there were in reality thousands. And he found that a large proportion of the nebula can be resolved into stars. He held that these, therefore, may be looked upon as external universes, resembling that great system of stars of which our sun is a member. We need not, at this point, dwell upon the distinction which Herschel drew between nebule of this sort, and those objects which he held (and as we now know, justly) to be true clouds, formed of some vaporous substance, of the actual nature of which he forbore to express an opinion. Let it suffice to remark that in whatever mode those vaporous nebulæ might be supposed to be formed, it was clear to Herschel that they cannot be held to lie necessarily beyond the system of the fixed stars, as he held to be certainly the case with the stellar nebulæ.

Since Herschel's day a multitude

of important discoveries have been made. His son, the present Sir John Herschel, carried the system of star-gaugings over the southern heavens, having first trained himself for the work by verifying Sir William's northern star-gaugings. The eminent astronomer Struve and others have applied a series of tests to the basis of Herschel's theory of the universe. Increased telescopic power has been applied to the examination of the nebula. And lastly, a mode of research more wonderful than the boldest pioneers of science had ventured to hope for has been applied to determine what the stars and nebulæ really are, nay even the very elements of which they are constituted.

Therefore we stand in a position so far in advance of that to which it was in Herschel's power to attain, that the attempt to modify his theories need no longer be thought to savour of undue boldness. Half

a century does not pass without bringing a vast extension of knowledge, and certainly the last halfcentury has been no exception to this rule; insomuch that could the great astronomer take his place again among us, and become cognisant of the vast strides which his favourite science has made since he left us, he would be the first to point out that many of his views required to be modified or even to be wholly abandoned.

For instance, let us consider the meaning of the following observation made by the younger Herschel. While 'sweeping' the southern heavens, this eminent astronomer noticed occasionally the existence of faint outlying streamers belonging to the Milky Way, yet not only irresolvable into stars, but so exceedingly distant that he could scarcely speak of them as really visible. He was sensible of their existence, but when the eye was turned directly upon them they vanished, insomuch that, he says, 'the

idea of illusion has repeatedly arisen subsequently,' yet when he came to map down the places where these phantom star-streams had been detected, he found that they formed regular branches of the galactic system.

Now these outlying star-streams prove first of all that the star-system is not disc-shaped, but spiral in figure. Between the stars which form the ordinary streams of the Milky Way, and those which form the phantom streams there must lie regions in which stars are either altogether wanting or strewn with much less profusion than in either the nearer or the farther stream.

But this is not the only nor the chief conclusion which may be drawn from the existence of the almost evanescent star-streams. According to Herschel's views the stars which compose those streams are only faint through enormity of distance. They may be as large as our sun, many of them perhaps far larger. And between them there may yawn distances as large as those which separate us from Arcturus or Aldebaran. Now this being so, the outlying parts of our own sidereal system being removed so far from us as to be all but evanescent in Herschel's splendid reflector-how much greater ought to be the faintness of the sidereal systems which lie outside ours! If the nebulæ are really such systems, and made up of suns like our own, then not only ought Herschel's great reflector to fail in rendering them visible, but even Lord Rosse's noble mirror would require to be increased a hundredfold in power before we could see them. For clearly the nebulæ, which appear as mere tiny specks upon the vault of heaven, must be very much farther away than the confines of our system, if they are comparable with it in size.

Therefore we must have 'of two things one.' Either the confines of our sidereal system are constituted

very differently from the parts in our neighbourhood; or the nebulæ are constituted very differently from the sidereal system. We say, of two things one, meaning that one of the two views must be true; but it is plain that there is nothing to prevent both being true.

We may next come to the inquiry whether these views are severally supported by any special evidence. Now as to the first, it happens that the southern heavens surveyed by the younger Herschel afford evidence such as Sir William Herschel was not possessed of. The former has seen places in the southern skies where the outline of the Milky Way is so sharply defined, that even in the telescope the sudden change from a background of black sky to the sprinkled light of the galaxy is not lost. One half of the field of view will exhibit the former aspect, the other the latter. Now if we consider a cloud, or a dense flight of birds, or any cluster of objects exhibiting a well defined outline, we see at once what that well defined outline means. It signifies that the eye is directed along the edge or surface of a distinct cluster of objects -in one case globules of water, in another birds, and so on-and the idea is at once precluded that the eye is within the cluster of whatever sort that cluster may be. Therefore the theory that the sun forms one of a system of stars spread pretty uniformly over a disc-shaped space must be given up; for were it true, the approach to the Milky Way would always be gradual.

When we add that in the southern skies the Milky Way presents the most fantastic configuration, here expanding into fan-shaped masses, there winding about in a multitude of strange convolutions, here suddenly narrowing into a bright neck or isthmus, there exhibiting a nearly circular vacancy, it becomes clear that the galaxy cannot have the figure assigned to it by Sir W. Herschel.

It must consist of streams and sprays of stars at different distances. Such streams by their fantastic convolutions serve to explain all the pecularities of the galaxy's structure.

And next, have we any evidence that the nebulæ are not really beyond the galaxy, but are mixed up with the sidereal system? It appears to me that we have.

Sir William Herschel noticed that there are places where the nebulæ are much more densely crowded than elsewhere, and he was disposed to suspect that precisely as the stars by their aggregation form the zone of the Milky Way, so there is a zone of nebulæ. But when Sir John Herschel had completed the survey of the heavens it was found that a very different law of distribution made its appearance. Instead of being collected in a zone or band around the heavens, the nebulæ are arranged in two distinct but irregular clusters, separated by a well marked zone almost entirely free from nebulæ. And this zone coincides almost exactly with the Milky Way.

What are we to understand by so special an arrangement as this? A modern astronomer says it clearly proves that the nebulæ do not belong to the star-world; but I can see no escape from an exactly opposite view. A simple illustration will serve to exhibit the nature of the case. Suppose a person found a space of ground on which gravel was arranged in the form of a ring, and that rough stones were thickly spread over the whole space except the gravel ring, would he conclude that there was no association be

tween the arrangement of the gravel and the arrangement of the stones, because few stones were to be found on or near the gravel? Would he not rather find in this peculiarity distinct evidence that there was some association? He would, we think, argue that the gravel had been collected into one place and

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