gunners will tell you at a glance the exact height of any machine flying over their position." 1 These men had used to good purpose their natural powers.

In finding out the sizes—the diameters—of heavenly bodies, the Sun, the Moon, the planets, variations on the method above described are followed. The general principles underlying are the same.

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I will fear you, O Stars, never more.

I have felt it! Go on, while the world is asleep,

Golden islands, fast moored in God's infinite deep.

Hark, hark, to the words of sweet fashion, the harpings of yore! How they sang to Him, seer and saint, in the far-away lands; 'The Heavens are the work of Thy Hands;

They shall perish, but Thou shalt endure;

Yea, they all shall wax old—

But Thy throne is established, O God, and Thy years are made

sure,

They shall perish, but Thou shalt endure

They shall pass like a tale that is told.'"

JEAN INGELOW.

1 Four Years in the Royal Flying Corps, by J. T. B. McCudden, V.C

PART X

OUR OWN GREAT SUN

I. ONE AMONG MANY

FROM worlds we pass now to STARS-to bodies so intensely heated as to shine by their own intrinsic brilliance, not merely with reflected light.

Some years ago, in a certain address given in public by a well-read man-only, not well-read on astronomical subjects—a very curious assertion was made. "Put out the Sun," the speaker said, Iand all the stars will cease to shine."

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It was difficult to believe that he really meant what he said. But again and again, with added emphasis, he made the same statement, till it became impossible to question his intention.

If he had said, "Put out the Sun and all the planets of the Solar System will cease to shine," he would have been quite right. For the planets depend, entirely or mainly, on the Sun for their shining; but the stars do not so depend. If you could, by any possibility, "put out the Sun," his worlds and moons would sink into darkness, becoming invisible, except perhaps for a very faint light from the big twins, visible at no great distance. But the stars would not vanish from our sky. They would remain just as bright as they were before.

Many people, as I have had to say earlier, find an odd difficulty in distinguishing between stars and planets. Again and again they are told that stars are suns, and that planets are worlds; and still their confusion of mind goes on.

Yet really the distinction is not so very hard to grasp, and the seeing of it is needful to any sort of understanding of the heavens.

Another speaker I can recall, who made a no less. astounding remark. "When you see a lovely Moon, and all its stars circling round it," he said, and how he carried on the sentence I have forgotten. That was enough.

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We may kindly hope that by "circling round" he really meant " encircling." encircling." In a sense one may suggest that the stars seen round about in the neighbourhood of the Moon at any particular time do perhaps seem to 99 encircle it, though in no sense can they be said to "circle round" it. But, its stars" is a phrase absolutely without sense. No stars in all the heavens can be said to belong to our tiny Moon.

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Our Sun is a star, brother to all those twinkling points which lie scattered over the sky; and each separate star, so far as we can tell, is in its measure a sun, larger or smaller, brighter or dimmer, than our Sun. True, some suns may gradually, in the course of centuries or millenniums, change into worlds, parting slowly with their heat, becoming cool and dim, but perhaps still warmed and lighted by some other near and more powerful sun. But so does a boy change into a man; so does a sapling change into a tree; yet we do not