drawn from the interstellar spaces. And so far as can be judged no other theory than these two can be imagined.

Now, whether we regard the giant planets as still engaged in the work of comet ejection or suppose that they have long since ceased to possess the powers necessary for that work, we have alike a curious subject of contemplation. In one case we see that a strange variety exists within the planetary system, where our earth and her fellow minor planets are fit abodes for life, while the giant planets are in a state of intense activity. In the other we see that a strange difference exists between the present condition of the outer planets and their condition in long past ages. I do not know which thought is the more suggestive; but I may note in passing that both thoughts may be admitted at the same time, and that in fact it is altogether more probable that both are just than that one must be rejected in favour of the other. Truly, when we view our solar system in the light of such considerations as these, we begin to see how much more wonderful the planetary scheme is than it has been represented in the text books of astronomy. We no longer are a uniform system, inert and lifeless, so far at least as life is measured by change, but a scheme full of variety, instinct with energy and vitality, changed in all parts from the condition it once had, changing in all parts towards new conditions-a living, growing, developing system, a fit world of life to be ruled over by the mighty,

ever active sun. As we contemplate these wonders, we seem to find a new meaning in the words of the Psalmist, 'The heavens declare the glory of God; and the firmament sheweth His handywork. There is neither speech nor language, but their voices are heard among them.'

THE EARTH'S JOURNEY THROUGH SHOWERS.

THERE are some facts in astronomy the real significance of which scarcely strikes us as they are ordinarily presented. We note with more or less interest, perhaps with wonder, a series of statements in which great distances and large masses are referred to with an imposing array of figures, but we fail to recognise adequately what the statements mean. This is particularly the case with some of the more recent discoveries made by astronomers. They are so pregnant with meaning, so stupendous, not only in their direct significance, but in the inferences which flow from them, that time is required even to view them aright, and much more time to realise their full significance.

Perhaps there is no department of astronomy to which these remarks are more strikingly applicable than to meteoric astronomy. I have already touched on some of the remarkable inferences, as to cosmical relations, which may be deduced from recent discoveries respecting meteors and meteor-systems. I propose now to touch on the subject in its terrestrial aspect: to show what is

actually taking place as our earth urges her way on her wide orbit round the sun, saluted on all sides by meteors— Pelted with star dust, stoned with meteor balls

though not always exposed to meteor showers of equal heaviness.

It is perhaps sufficiently startling to be told at the outset that nearly all shooting stars-nine hundred and ninety-nine out of every thousand, certainly—are missiles which rush towards the earth with a velocity far exceeding that of the swiftest cannon-ball. They are not missiles which miss their mark. They do not, as was once thought, merely graze our atmosphere. They come straight towards the earth, and many among them must make straight towards living creatures on the earth. And though they are for the most part small, they are by no means so small as to be unable to destroy life. Their swift motions make up for their smallness, and the actual momentum of some of the tiniest of these bodies is equivalent to the momentum of a cannon-ball.

We might afford to make little of the danger (for danger there would be but for a circumstance presently to be mentioned) were the number of these bodies small. If ten or twenty saluted the earth during the twenty-four hours, the chance that even in the course of a century any living creature would be struck would be small. For the earth is large, and living creatures occupy but a small portion of its surface. But, I think, many among my

readers have no adequate conception of the enormous number of meteors which each year fall upon the earth. A million a year would bring some degree of danger. But the actual number is far greater. It has been estimated by Professor Simon Newcombe, of America, on grounds which are perfectly reliable, that including telescopic meteors (that is, meteors so small as only to be visible when they happen to pass across the field of view of a telescope) no less than 146,000 millions of meteoric bodies fall each year upon the earth. If one in a thousand struck a human being the inhabitants of the earth would be decimated in a single year.

How then is it, it may be asked, that we never hear of even an accident from ordinary meteors, though accidents from aerolites have not been altogether unknown? Here is this great vessel, the earth, sailing through space, and saluted every twenty-four hours by 400 millions of missiles, each flying towards her with many times the velocity of the swiftest cannon-ball. This goes on by day and by night, when living creatures are far from shelter as well as when they are protected in their various abodes; and yet the inhabitants of earth are perfectly safe from all danger. It is not merely that they have been so far fortunate as to escape hitherto, but that they really are as safe as though the earth were protected by those three-feet armour plates which will one day, we are told, defend our floating batteries.

The real protection of the earth is the air which sur