Eighth Reader Part 20

Strange forests these are to us. No oaks, no elms, no beeches, no birches, no palms, nor many colored wild flowers are there. The deciduous plants so common in our modern forests are nowhere found; but enormous club mosses are seen, as well as splendid pines and an abundance of ancient trees with waving, frondlike leaves. Here also are graceful tree ferns and countless ferns of lower growth filling up all gaps.

[Ill.u.s.tration]

No wild quadrupeds are yet in existence, and the silent forests are enlivened only by the stirring of the breeze among the trees or the occasional hum of monstrous insects. But upon the margin of yonder stream a huge four-footed creature creeps slowly along. He looks much like a gigantic salamander, and his broad, soft feet make deep impressions in the yielding mud.

No sunshine but only a gleam of light can creep through the misty atmosphere. The earth seems clothed in a garment of clouds, and the air is positively reeking with damp warmth, like the air of a hothouse. This explains the luxuriant growth of foliage.

Could we thus stand upon the hilltops and keep watch through the long coal building ages, we should see generation after generation of forest trees and underwoods living, withering, dying, falling to earth. Slowly a layer of dead and decaying vegetation thus collects, over which the forest flourishes still--tree for tree, and shrub for shrub, springing up in the place of each one that dies.

Then, after a very long time, through the working of mighty underground forces, the broad lands sink a little way--perhaps only a few feet--and the ocean tide rushes in, overwhelming the forests, trees and plants and living creatures, in one dire desolation.--No, not dire, for the ruin is not objectless or needless. It is all a part of the wonderful preparation for the life of man on earth.

Under the waves lie the overwhelmed forests--prostrate trunks and broken stumps in countless numbers overspreading the gathered vegetable remains of centuries before. Upon these the sea builds a protective covering of sand or mud, more or less thick. Here sea creatures come to live, fishes swim hungrily to and fro, and sh.e.l.lfishes die in the mud which, by and by, is to become firm rock with stony animal remains embedded in it.

After a while the land rises again to its former position. There are bare, sandy flats as before, but they do not remain bare. Lichens and hardier plants find a home. The light spores of the ancient forest trees take root and grow, and luxuriant forests, like those of old, spring again into being. Upon river and lake bottoms, and over the low damp lands, rich layers of decaying vegetation again collect. Then once more the land sinks and the ocean tide pours in; and another sandy or muddy stratum is built up on the overflowed lands. Thus the second layer of forest growth is buried like the first, and both lie quietly through the long ages following, hidden from sight, slowly changing in their substance from wood to shining coal.

Thus time after time, the land rose and sank, rose and sank, again and again. Not the whole continent is believed to have risen or sunk at the same time; but here at one period, there at another period, the movements probably went on.

The greater part of the vegetable ma.s.s decayed slowly; but when the final ruin of the forest came, whole trunks were snapped off close to the roots and flung down. These are now found in numbers on the tops of the coal layers, the barks being flattened and changed to shining black coal.

How wonderful the tale of those ancient days told to us by these buried forests!

FOOTNOTE:

[Footnote 45: By Agnes Giberne, an English writer on scientific subjects.]

SOMETHING ABOUT THE MOON[46]

I am going to say a few words about the moon; but there are many matters relating to her of great interest which I must leave untouched, for the simple reason that there is not room to speak of them in a single paper.

Thus the moon's changes of shape from the horned moon to the half, and thence to the full moon, with the following changes from full to half, and so to the horned form again, are well worth studying; but I should want all the s.p.a.ce I am going to occupy, merely to explain properly those changes alone.

So a study of the way in which the moon rules the tides would, I am sure, interest every thoughtful reader; but there is not room for it here.

Let us now turn to consider the moon; not as the light which makes our nights beautiful, nor as the body which governs the mighty ocean in its tidal sway, but as another world,--the companion planet of the earth.

It has always been a matter not only of the deepest curiosity, but of the greatest scientific import, whether other planets, and particularly our own satellite, are inhabited or exhibit any traces whatever of animal or vegetable life.

One or two astronomers have claimed the discovery of vegetation on the moon's surface by reason of the periodic appearance of a greenish tint; but as the power of the telescope can bring the moon to within only about a hundred and twenty miles of us, these alleged appearances cannot be satisfactorily verified.

The moon is a globe, two thousand one hundred and sixty-five miles in diameter; very much less, therefore, than our earth, which has a diameter of about seven thousand nine hundred and twenty miles.

Thus the moon's surface is less than one thirteenth of the earth's.

Instead of two hundred millions of square miles as the earth has, the moon has only about fourteen millions of square miles, or about the same surface as North and South America together, without the great American Islands of the Arctic regions.

The volume of the earth exceeds that of the moon more than forty-nine times. But the moon's substance is somewhat lighter. Thus the ma.s.s, or quant.i.ty of matter in the moon, instead of being a forty-ninth part of the earth's, is about an eighty-first part.

This small companion world travels like our own earth around the sun, at a distance of ninety-three millions of miles. The path of the moon around the sun is, in fact, so nearly the same as that of the earth that it would be almost impossible to distinguish one from the other, if they were both drawn on a sheet of paper a foot or so in diameter.

You may perhaps be surprised to find me thus saying that the moon travels round the sun, when you have been accustomed to hear that the moon travels round the earth. In reality, however, it is round the sun the moon travels, though certainly the moon and the earth circle around each other.

The distance of the moon from the earth is not always the same; but the average, or mean distance, amounts to about two hundred and thirty-eight thousand eight hundred and twenty-eight miles. This is the distance between the centers of the two globes. With this distance separating them, the companion worlds--the earth and the moon--circle round each other, as they both travel round the central sun.

But now you will be curious to learn whether our companion planet, the moon, really presents the appearance of a world, when studied with a powerful telescope.

If we judged the moon in this way, we should say that she is not only not inhabited by living creatures, but that she could not possibly be inhabited. What is it that makes our earth a fit abode for us who live upon it? Her surface is divided into land and water. We live on the land; but without the water we should perish.

Were there no water, there would be no clouds, no rain, no snow, no rivers, brooks, or other streams. Without these, there could be no vegetable life; and without vegetable life, there could be no animal life, even if animals themselves could live without water.

Yet again, the earth's globe is enwrapped in an atmosphere,--the air we breathe. Without this air, neither animals nor vegetables could live. I might go further and show other features of the earth, which we are at present justified in regarding as essential to the mere existence, and still more to the comfort, of creatures living upon the earth.

Now, before the telescope was invented, many astronomers believed that there was water on the moon, and probably air also. But as soon as Galileo examined the moon with his largest telescope (and a very weak telescope it was), he found that whatever the dark parts of the moon may be, they certainly are not seas.

More and more powerful telescopes have since been turned on the moon. It has been shown that there are not only no seas, but no rivers, pools, lakes, or other water surfaces. No clouds are ever seen to gather over any part of the moon's surface. In fact, nothing has ever yet been seen on the moon which suggests in the slightest degree the existence of water on her surface, or even that water could at present possibly exist; and, of course, without water it is safe to infer there could be neither vegetable nor animal existence.

It would seem, then, that apart from the absence of air on the moon, there is such an entire absence of water that no creatures now living on the earth could possibly exist upon the moon. Certainly man could not exist there, nor could animals belonging to any except the lowest orders of animal life.

FOOTNOTE:

[Footnote 46: By Richard A. Proctor, a noted English astronomer (1837-1888).]

THE COMING OF THE BIRDS[47]

I know the trusty almanac Of the punctual coming-back, On their due days, of the birds.

I marked them yestermorn, A flock of finches darting Beneath the crystal arch, Piping, as they flew, a march,-- Belike the one they used in parting Last year from yon oak or larch; Dusky sparrows in a crowd, Diving, darting northward free, Suddenly betook them all, Every one to his hole in the wall, Or to his niche in the apple tree.

I greet with joy the choral trains Fresh from palms and Cuba's canes.

Best gems of Nature's cabinet, With dews of tropic morning wet, Beloved of children, bards and Spring, O birds, your perfect virtues bring, Your song, your forms, your rhythmic flight, Your manners for the heart's delight; Nestle in hedge, or barn, or roof, Here weave your chamber weather-proof, Forgive our harms, and condescend To man, as to a lubber friend, And, generous, teach his awkward race Courage and probity and grace!

FOOTNOTE:

[Footnote 47: By Ralph Waldo Emerson, an American poet and philosopher (1803-1882).]

THE RETURN OF THE BIRDS[48]

The coming and going of the birds is more or less a mystery and a surprise. We go out in the morning, and no thrush or finch is to be heard; we go out again, and every tree and grove is musical; yet again, and all is silent. Who saw them come? Who saw them depart?