of the sky at a view. Now, if the two following methods were available for the enquiry (by combining the observations made by a great number of persons), is it not manifest which would be the most instructive? By one let the sky be assumed divided by a series of circles parallel to the horizon, and by a series of half-circles square to the horizon, and therefore all crossing at the point overhead; and let the enquirer be supplied with lists informing him of the number of clouds in these various sections of the sky. By the other let a picture be painted, in which all the features of the sky as ascertained by the different observers are combined artistically into a single view.

I think no one can doubt that while clear ideas would be formed from the study of the picture, not all the statisticians in the world could derive just views from the analysis of the lists of numbers.

I propose in my next chapter to tell the reader some of the facts which come into view, when pictures of the star depths are constructed on a certain plan devised to make them as instructive as possible, and then to indicate a scheme which I have devised for continuing and extending the enquiry. I think I shall be able to show not only that there are reasons for hoping that a true general theory of the stellar system may one day be formed, but that the facts which are already known, or may be inferred, are full of interest, and exhibit the universe of stars as far more wonderful in extent, in variety of structure, and in complexity of detail than had hitherto been supposed.

CHARTING THE STAR DEPTHS.

In my last chapter I pointed to the necessity of charting the heavens, even as they would be seen by means of a very powerful telescope, if we really hope to ascertain the laws of the sidereal universe.

But it is manifest that we must not begin by thus combining in a single picture all that such a telescope would reveal. For let it be considered how incomprehensible the scene so presented would appear to us. The dome of heaven, even as we see it with the naked eye, presents a perplexing display. Those suns seem as the sands on the sea-shore for multitude; the glorious streams of stars called the Milky Way lie in complex clouds before us. The problem even thus presented appears to lie beyond our powers. What, then, would be the scene when for every star we see thousands and tens of thousands would be revealed? How should we be perplexed when the clouds of the Milky Way, as now seen, appeared only as the brightest masses in a perfect sky of star clouds, in which every variety of form, of aggregation, and of constitution should be presented to our view!

Even more incomprehensible would be the streams of cloudlets which astronomers call nebulæ. Yet even there the wonders of the scene would not be at an end. For by our assumption the powers of the human observer would be so enhanced that he would perceive the motions of all the millions of stars, one group tending hither, another thither, one region instinct with diverse and seemingly random motions, another bearing onwards its wealth of stars in one compact body, if a system could be called compact whose several orbs were seen to be separated from each other by thousands of millions of miles. Even our solar system, if viewed under such conditions, would present a most perplexing scheme to one not already acquainted with the laws pervading it; but the orbs of the stellar universe are a million times more numerous, are arranged according to laws infinitely more complex, travel with motions infinitely more varied: and though we need not doubt that, if we could but perceive the real dependence of the various parts upon each other, a perfect harmony would be found to pervade every portion, yet that harmony can only be manifest to Him in whose eyes a thousand years are as one day.

We must approach the solution of the great problem, then-that is, such solution as we are likely to attain to -by gradual steps. We must not attempt to survey the whole domain of sidereal astronomy at once, but gradually open our eyes to its full extent. This expression is not. simply figurative. The conception of a gradually in

creasing telescopic power corresponds to the idea of a gradual opening of the eyes. Half closed at first, the eyes of our imaginary enquirer are veiled from the overpowering glories of the great star-multitude, they reach not very far beyond the range of ordinary human vision; but gradually they become better able to endure these wonderful glories, and to understand the full significance of the scene; then they are opened to fresh wonders: until at length all that the powers of the telescope can reveal to man is disclosed to their view.

In working, then, by the method of charting I began (for I may as well note that I have been practically alone in this work) by charting the stars that we can see, according to a plan by which the laws of distribution should be clearly recognised; for the charts I drew were so contrived that equal spaces on the celestial sphere should be represented by equal spaces in the chart. It quickly became clear that the stars are not scattered at all uniformly over the heavens. There are rich and poor regions; and these are so arranged that while the whole of the galactic region is exceedingly rich in naked-eye stars, two opposite rich regions, one in the northern and the other in the southern heavens, are separated from each other (except where the Milky Way on opposite sides passes from one to the other) by singularly barren regions. It appears a noteworthy circumstance that near the centre of the great southern rich region are found those two wonderful objects called the Magellanic Clouds, vast

globe-shaped conglomerations (scarcely any other word seems so suitable) in which are contained not only myriads of stars of all orders of magnitude after the seventh, but also every kind of star cloudlet.

This was only a first step; though I may remark that to this particular part of my work alone I was able to apply a somewhat novel but very effective method of research. It seemed desirable to ascertain how far the apparent aggregation of stars in the rich regions I have mentioned, and their segregation from other regions, was a real phenomenon-in other words, to test the eye's power of forming an opinion on this point. I therefore made separate copies of the northern and southern charts on the smoothest and most uniform paper I could obtain, and then cut out the poor and rich parts of the chart and weighed them in a very delicate balance. This process told me their relative extent better than any way of measurement applicable to such strangely shaped regions. I found that, as might have been expected, the eye had judged quite correctly, and that when comparison was made between the poorer and richer regions, the wealth of the star distribution was in some of the latter regions fully five times as great as in some of the former.

But already a remarkable and important feature of star distribution had come to light. It was manifest that the Milky Way is a region much more richly strewn with naked-eye stars than are other parts of the heavens. Now,