The Strange Adventures of a Pebble

by Hallam Hawksworth

CHAPTER IV

(APRIL)

Now the noisy winds are still;

April's coming up the hill!

All the spring is in her train,

Led by shining ranks of rain.

—Mary Mapes Dodge.

THE APRIL RAINS AND THE WORK OF THE RIVERS

I always liked the little boy's definition of a river system. "Rivers that empty into other rivers that empty into other rivers that empty into the sea."

What is still more interesting, the sea at the same time is emptying into the rivers; for the waters of all the lands and the waters of all the seas, are one, and what the rivers give to the sea the sea returns in the rain clouds that are blown landward by the winds. The Earth's waters are thus always in circulation like the blood in our bodies. In making this endless circuit they do an immense amount of useful and beautiful work, and have many strange and curious ways of doing it. It's a great family affair of the Waters people. Everybody has a hand in it, from the baby rill that toddles across the country road, the brook it meets in the meadow, the creek that runs through the wood, and the river into which it flows, to the greater river which carries forward these mingled waters to the sea.

THE MISSISSIPPI RIVER SYSTEM

I. What I Brought Back from the Creek

I met a rain-drop once that had followed the thing through, starting where a little creek began, and got such a load of information I could hardly carry it, about the wonderful part the rivers take and have taken in the making and remaking of the world.

We see the April rains carve fairy canyons in the soft clay of the roadside or the creek, but it is hard to realize, as we stand on some pinnacle of the Alps and look out over the deep and wide valleys, the gorges, the cliffs, and mountains cut in two, that all are but the handiwork of the rain-drops banded together as flowing waters. For a long time this was questioned by scientific men, because the idea so upset the old theory that great changes in this world of ours came about all of a sudden and from causes not at work in these days. Now, however, nobody doubts that the big things are done by the little people, working together over long periods of time; little snowflakes, little rain-drops, little cells in plants. As a result, the Alps, so far as the expression of their faces is concerned, are as little like the Alps of the past as the face of the old farm of to-day is like the farm of those ancient yesterdays, when the brontosaurus browsed where old Dobbin is nipping the meadow grass and the mammoth ate the leaves of trees that stood where White Face is thoughtfully chewing her cud in the shade.

HOW THEY STUDY GEOGRAPHY IN BOSTON

This is what, in the Boston schools, they call an "umbrella party." "Umbrella party" sounds much more attractive than "geography lesson," but as a matter of fact it is a geography lesson and a fine one. As soon as they get off that brick pavement the boys and girls will see those rain-drops cutting out little Mississippi River systems, filling little Great Lakes, plunging over Niagaras two inches high!

Right where you sit reading, perhaps, the land used to be buried two miles deep beneath rocks which have been worn away by wind and rain and by rivers which vanished long ago. Everything has been so changed that if the old scenery should be put back you would be lost right on the home farm.

WHERE YOU CAN JUMP ACROSS THE MISSISSIPPI

Wrinkles in the earth and in the mountainsides make the first troughs for the streamlets and the rivers, and then the running water itself digs these natural channels deeper. Many rivers begin as streamlets flowing out of springs. The great Mississippi began as a baby, just like the rest of us. You can jump across it still if you go up to its source. Springs not only start rivers in life but go on feeding them. Most large river systems get secret gifts in this way, as they flow along, from thousands of springs that empty into them or their tributaries.

So springs start and feed the rivers. Now what do you suppose starts the springs? Rain-drops stored away in big stone "safes," much as a small boy stores away pennies in his tin bank! The water of rains and melting snows, passing down through the soil, soaks into the little chambers or pores in such rocks as sandstone and limestone, and keeps going on down until it comes to a bed of hard stone, such as slate or granite, into which it cannot soak.

THE SPRING WHEN EMPTY

THE SPRING WHEN FULL

THIS SPRING PLAYS IT'S A TOWN PUMP

These two pictures show an intermittent spring about five miles from Singer Glenn, Virginia, and there called the "Tide Spring." You can see where the idea of the tide comes in, but can you think why the spring seems to have a tide system all its own? You know what a siphon is. Well, think how a kind of siphon might be formed in rock, dissolved out by water flowing underground. Then look at the picture on the next page.

Now rock-beds, as you know, have a slope—some more, some less—owing to the wrinkling of the earth's crust. So the water, slowly trickling through the porous rock, forms a steady stream which runs down along the hard rock, as rain runs down a roof, and finally gushes out at some lower level.

HOW THE LITTLE SPRING WORKS ITS PUMP

This is how the pump of an intermittent spring is worked. Some portions of rock are dissolved by underground waters more readily than others and so cavities are sometimes formed, as shown. As long as the water in the reservoir is below the arch of the siphon-shaped outlet no water escapes, but as soon as it rises to the level of the arch the whole of the water is drawn off. Then the spring ceases to flow until the reservoir fills up again. You can empty water in the same way by using a bent tube of any kind. Can you tell why the water flows up-hill in this way? Remember what you know about air-pressure and then look up "siphon" in your encyclopædia.

You can be sure these companies of rain-drops, hurrying back to the light, don't fail to notice any cracks in the rocks along the way, and at such places they come gushing up with sparkle and dance; and the greater the dip of the rock beds the higher they dance, of course.

But it takes any one rain-drop so long to get back into the sunshine after it starts on its underground journey that you'd think it would forget how to dance at all! It isn't just the same rain-drop, to be sure, that goes into the ground and comes out again, because the rain-drops get all mixed up with each other as they move along, but just imagine some one rain-drop that fell, say, on a hilltop on the day a baby was born in a valley five miles away, where there was a spring in a shady hollow near the baby's home. By the time that rain-drop got down to the spring the baby would be old enough to vote!

Yet this is a very good thing for the rivers and the rest of us—this slow travel of the underground water, whether it comes out in springs or simply seeps through the soil as most of that which supplies the rivers does. Otherwise, if all the water of the rains went directly into the rivers we would have floods after every wet spell and empty river beds between times.

Here's another river rebus. How do rivers grow longer at the top? All rivers grow at their source because their headwaters eat back into the rocks and the soil, just as the rain wears away the head of any gully. Where the rock is soft they eat back faster. The Mohawk River in New York State probably wouldn't have amounted to anything if it hadn't done this very thing. From Albany westward past Utica runs a belt of shale, a weak stone, but here so soft that the surface of it crumbles back to clay in every winter's frost. Into this the Mohawk, which in past ages was only a little stream, has eaten back its way until now it is over a hundred miles long.

But sometimes rivers are so big the very first day they come into the world that you may say they are born half grown. You find them, among other places, in the mountains of California. Nearly all the water from the melting snows on Mount Shasta sinks at once into the porous lava fields of the mountain slopes, and after wandering about in the hidden veins comes out, filtered and cool, in the form of large springs which make rivers that set out on their life journeys without ever having been babies at all so far as you can see. The Shasta River is one of these. The McCloud is another. It gushes forth suddenly from a lava bluff in a roaring spring seventy-five yards across, two-thirds of the width of the river in its widest part. The River Jordan in the Holy Land begins in one of these great springs at the foot of Mount Hermon.

From Norton's "Elements of Geology." By permission of Ginn and Company

HOW MOST OF EUROPE'S RIVERS GET THEIR START

Most of the important rivers of Europe start as streams of ice-water, flowing out of glaciers. Notice the boulders along the side of the stream. They also came out of the body of the glacier, where, as we shall see when we take up "The Stones of the Field" in [Chagter VII], the boulders that rode south with the glaciers got most of their roundness.

We know already what a hand the glaciers had in the Ice Age in shaping the course and conduct of rivers, and you may be sure they have something to do with the making of rivers to-day. The under side of a glacier gets warmed from three sources: (1) its own pressure; (2) the friction as it moves; and (3) the heat from the inside of the earth which, on account of this thick ice blanket, can't get away into the air as it does elsewhere. This heat melts the ice and, as we know, there is water melting also on the surface of glaciers and in the crevasses. Beside all this the water of rains falls upon the glacier so that there is plenty of water to make rivers, and we always find streams of water running from a glacier's front. Most of the rivers of Central Europe start in this way.

THE BEAUTY OF THE BRIDAL VEIL

And, although they didn't make the rivers themselves, the Ice Age Glaciers are held responsible for the fact that many little rivers always have to jump to catch the train. That is to say, they come tumbling over falls to join the larger streams into which they empty. The reason of this is that when, in the Ice Age, the glaciers filled the river valleys the larger glaciers in a main valley dug below the tributary valleys and so left the mouths of the tributary rivers high up on the main valley's walls. The famous "Bridal Veil" in the Yosemite is one of these side valley falls. The fall—900 feet—is so great that the water widens to a fleecy foam and waves back and forth in the wind like a gauzy veil and, instead of a roar like Niagara, it makes a rustling sound like silk.

While some rivers come hurrying down like that—as if they really were afraid the larger river would go off and leave them—others, like the Amazon, roll on as stately as a Lord Mayor's procession. But the waters of all are on their way to the sea. The rock layers, owing to the wrinkling of the earth as it shrinks, are nowhere level, so flowing water is always on a down grade, sloping toward the sea or toward other land that does slope toward the sea. Then remember too as the sea bottom keeps sinking the continents keep rising, which increases the pitch of the land.

JUMPING TO CATCH THE TRAIN

See the famous Bridal Veil Falls in the Yosemite Valley hurrying down to reach the river below. As the stream descends, it broadens into a beautiful, filmy veil.

All very simple, but none the less grand and impressive. Ruskin, in one of the noblest of his passages, says:

"[All water courses], from the inch-deep streamlet that crosses the village land in trembling clearness to the massy and silent march of the Amazon and the Ganges, owe their play and power to the ordained elevations of the earth; [to] paths prepared for them by which at some appointed rate of journey they must evermore descend, sometimes slow and sometimes swift, but never pausing, the gateways of guarding mountains opened for them in cleft and chasm, and from afar off the great heart of the sea calling them to itself."

That's a poetic way of putting it, but it's a fact nevertheless.

II. The Human Nature in Rivers

There's a lot of human nature in rivers. To begin with, as we might suppose, they do the most playing and the least work when they are young. Brooks will be brooks, you know!

What pretty ways they have in babyhood! Kissing the pebbles, crooning, bubbling, chattering, playing, they are big Mississippis or great oceans that, like Homer's ocean river, flow around the world. Their bubbles are ships, sometimes wrecked on dreadful headlands along the shores.

THE CHANT OF THE WATERFALLS

Waterfalls are found only in young streams and more often as you near the source. Older streams have worn down their beds more nearly to a level and, as we all know, more rivers begin among the mountains and highlands than in the lower lands. In the mountain regions there are plenty of rocks and cliffs to jump from, and the rivers, you may be sure, make the most of their opportunities. At such falls as the Bridal Veil they jump so far they are turned into white cascades, and as you climb the cliff beside them and feel the wind wafting spray in your face you hear the music of their songs. The more or less regular dash of the water as it swings back and forth in the wind gives that chanting sound described in waterfall poetry.

"BROOKS WILL BE BROOKS, YOU KNOW!"

Our baby river of the meadow seems to be playing it has a Niagara Falls of its own, "Rock of Ages" and all! See the "huge mass" of rock at the foot of the falls; and the rapids?

Like children these dancing, singing rivers love pictures and color. You see that in the rainbow tints of the spray as the sunlight strikes the air bubbles the waterfall "blows"; in the green of its waters turned to gray in the foam; in the reflections of mountain, sky, and cloud in the smooth stretches below the falls.

And, like pebbles and other little people, rivers love to play in the rain. My! What a time! In a storm, with a gray flood pouring from the sky, you hear, mingled with the voice of wind and rain, the swash and gurgle of the eddies as the river goes along in its dance, wild with the joy of it all. In a mountain stream during a heavy rain, with wind, you can also hear the waves dashing against the rocks along the shore or in the stream, and the smothered, bumping, rumbling made by the boulders on the bottom knocking against each other.

STORM CHORUS OF THE MOUNTAIN TORRENTS

From any high place during a mountain storm you can see twenty, yes, often a hundred torrents, and the noise of the water and the moving stones makes a wonderful storm chorus. Reclus compares the sound made by the stones to dull thunder.

WHERE TO LOOK FOR HIDING RIVERS

Rivers, both young and old, play hide and seek. Possibly the older rivers get to dreaming of their infancy when they were springs, and want to play they are springs again; anyhow, they disappear in the ground in one place and then come out laughing in another as if they really were springs! And how they must chuckle to themselves when they fool people into thinking they are brand new rivers! This happens sometimes, and so the river gets a different name at the place where it comes out from the name it bears up to the point where it disappears. Such hide-and-seek rivers are found in regions where it doesn't often rain. The Tujunga, which you cross in going from Los Angeles to San Francisco, is such a river. At one place in its course it comes out of a canyon, looks around a minute, and then disappears in the pebbles, sand and gravel of the plain. Down it goes until it reaches a bed of hard rock. Along this underground bed it runs until it gets to a place north of Cahuenga Peak, where it comes up in springs and flows into the Los Angeles River.

THE LOST RIVERS AND THE THOUSAND SPRINGS

These are the waters of some hidden tributaries of the Snake River gushing out as springs from its beautiful banks. The group is called "The Thousand Springs," and is supposed to be the reappearance of two "Lost Rivers" that disappeared back in the sand wastes.

Mountain lakes are where the lively little torrents stop to sleep. "The sea," says Ruskin, "seems only to pause; the mountain lake to sleep and to dream."

But after this sleep how they laugh and play—those baby rivers—as they go dancing over the pebbles and down the falls; for in these lakes they gather themselves together into a larger volume of water, and so, of course, flow on with increased energy.

"As soon as a stream is fairly over the lake lip it breaks into cascades, never for a moment halting, and scarce abating one jot of its glad energy until it reaches the next basin. Then swirling and curving drowsily (dropping off to sleep again!) through meadow and grove it breaks forth anew into gray rapids and falls, leaping and gliding in glorious exuberance of wild bound and dance down into another and yet another lake basin."[12]

[12] Muir, "The Sierra Nevada Mountains."

Just as it is with human beings, a river seems to grow more thoughtful and thrifty as it grows older; and, best of all, this thought and thrift is for others—for the people of the plant world along its banks and for its old parent, the sea. With the help of pebbles it puts money in its savings bank and pays it out from time to time.

In seasons of flood it carries loads and loads of pebbles along. As the flood goes down these pebbles are dropped and covered with the sediment that settles along its banks. Then these pebbles begin to decay and so enrich the soil. Later along comes another flood, takes the pebbles out of the bank, carries them farther along, and, as the waters go down, puts them back in the bank again. In course of time this kind of fresh food from the decaying pebbles gets carried into the sea, where it helps to furnish food and shell material for the shell-fish and raw material to be worked up by the sea's rock mills.

WAYS OF A WANDERING RIVER

III. The Machinery of the Rivers

To do all their great part in the world's work the rivers need only time, enthusiasm, patience, machinery, and tools. All these the rivers have, and the machinery they use and the engineering methods they follow are much more modern than we would suppose. Take, for example, the way in which rivers widen their banks. The current cuts with the greatest force on the outside of bends, and the motion and effect is practically that of a circular saw. This sawing is done on the largest scale where the current meanders. Swinging from side to side it cuts away both banks.

And what it cuts away it spreads over the valley by its back-and-forth motion, much as men spread dirt with scrapers when they are grading a road.

That's how crooked rivers make broad valleys. But they have to have the help of us pebbles, too. We're hard to get along without! Notice, the next time the river or the creek is up, the rolling, hopping motion of the pebbles as they are carried along by the rushing water. It is these pebbles grinding on the bottom and sides of the river's bed that help most in this kind of valley deepening and widening. In the same way we pebbles helped dig those grand affairs, the gorges and the canyons in the mountains. The Grand Canyon of the Colorado is a part of our work.

In the widening of valleys the circular saws of crooked streams are very useful, but there are other things at work. The rains dissolve the soil and wash the banks away and slope them down; Jack Frost, with his wedges, pries out both soil and rock; the little farmers with many feet—the burrowing animals and insects—and the famous farmer with no feet at all—the angleworm—loosen soil, and so help the river to carry it away; and the ice, when the river breaks up in the spring, chisels off the banks as it passes.

HOW RIVERS BUILD STONE BRIDGES

Natural bridges are made by the same agency that forms the intermittent springs—the dissolving power of water—and, like the springs, are characteristic of limestone regions because limestone is readily dissolved in water. In the little model of a limestone region "a" and "a" are "sink-holes"—saucer-shaped hollows dissolved and washed into funnels through which the surface water joins underground streams such as you see flowing beneath the two "bs," which are natural bridges in the making.

The lower picture shows just how one of the bridge-builders looks while at work, dissolving and wearing down the rock. The next two pictures will help tell you two other ways in which rivers make their own bridges.

If you have ever been in a machine-shop you must have noticed how a planing-mill works away on a job it has been set to do, without anybody watching it at all; and when it gets done with its job it stops, all by itself. Such machinery is called "automatic," because, to a certain extent, it runs its own affairs. A river, in planing down and reshaping valley scenery, has an automatic stop. When it has cut its valley down to sea level it stops, because, being then no higher than the sea, it can no longer flow toward it.

AFTER A FEW CUPS OF TEA

When winding rivers get a few cups of tea—that is, are in flood—they rush straight ahead and, while much of the water may for a time still go on around the bend, some of it is forced through openings in the rock and in time carves out a bridge. How they do this is shown in the upper diagram on [page 83].

But before this automatic stop shuts off their machinery the work that rivers do is immense. The Mississippi River carries enough solid matter to the Gulf every year to make a mountain a mile square and 268 feet high.

YOU KNOW THIS BRIDGE, OF COURSE

The Natural Bridge of Virginia is an example of still another style of river bridge-building. This bridge used to be part of the roof of a cave and remained after the rest of the roof fell in.

When ordinary people want to cross a mountain they have to climb over it. But do you know what a river does? It cuts its way right through and makes what is called a water-gap—a great gate of stone that is always open and through which the stream forever flows. All the river used was tools and time. The tools were the sand and pebbles it swept along. So in the course of ages, running like a band saw, the Potomac made the water-gap at Harper's Ferry, the Delaware River the Delaware Water-Gap.

HOW MOUNTAINS HELP MAKE THE WATER GATES

But how could a river do this? It couldn't flow up one side of the mountain and down the other, could it? No, certainly not. What then? Wherever you find a river cutting through a mountain range you may be sure the river was there before the mountains rose, and that the mountains rose so slowly the river kept right on in its old channel and wore down the rock under that channel as fast as the mountains rose; while, on either side, they could rise as high as they wanted to for all the river cared!

GROWING MOUNTAINS AND THE EARTHQUAKES

But suppose, before I had explained how water-gaps are made I had told you I could show you a mountain growing. You wouldn't have believed it. Regions in which mountains are still rising, as on our Pacific Coast, are liable to earthquakes. The reason is that as mountains rise the rock layers of which they are made are strained dreadfully. Every once in a while they crack and the rocks on either side of this crack grind against each other. This makes the earth shake, much as the house shakes when a heavy table is pushed across a bare floor.

If you want to see a job of river engineering that will make you catch your breath, look over into some of the river canyons and gorges of the West.

THE GREAT CUMBERLAND WATER-GAP

Here is the famous Cumberland Gap that the river cut through the mountains; so cutting a great figure in United States history, also, you remember. The picture shows the region as it looked in early days.

A mile isn't much straight ahead, but a mile straight down and you on your stomach, with your eyes just over the edge—it's an awful long way! Imagine yourself looking down a wall of rock like that, and the bottom of the abyss so far off that it looks blue—that's a canyon!

AND YET THAT LITTLE RIVER DID IT ALL!

And now we are going down into the vastest canyon in the world, a canyon so vast that it has already swallowed practically all the words in the dictionary suitable to such scenery and still remains undescribed—so all the skilled writers say who have tried their hands at it. This is the Grand Canyon of the Colorado. Do you remember how in "Alice in Wonderland" the cat disappeared and left nothing but its smile? Well, the first time you see the Grand Canyon you feel as if it had swallowed you and left nothing but your eyes! And when they tell you that it was all done by that little river that you can just make out threading its way along the bottom, you can't believe it! The total length of the river's gorge—a canyon is just a long gorge—is some 400 miles. The part of it known as the Grand Canyon is a yawning abyss of stone into which the river walls widen for a distance of 42 miles. The Lower Colorado River, that dug this chasm in the rock, flows through a vast table-land where rain seldom falls. But the river, which rises in the Rocky Mountains, has a constant supply of water from the mountain rains and the melting snow. The canyons you see branching from the main gorge in our picture were cut by the Colorado's tributaries. Working together on different sides, they carved out those rock masses that look like oriental temples and have been named accordingly—the temples of Brahma, Osiris, Zoroaster, and so on.

And here in this canyon is a splendid example of how the rivers, in addition to all their other labors, write history. They helped to lay down on the borders of the ancient sea the material out of which the rocks were made. It is in the leaves in such books of stone that the geologist reads the great events of world-making history. Moreover, the rivers may be said to cut the leaves of the book when they dig down through them, as in this immense library of the Grand Canyon.

From a photograph copyrighted by Fred Harvey

AND WE PEBBLES HELPED DIG THE GRAND CANYON, TOO!

River water alone couldn't cut those canyons—the Grand Canyon and the rest. The Colorado and its tributaries had to have grinding tools and the tools were the pebbles they dragged over their rock-beds; and thus, in the course of ages, wore them down and down and down.

Busy, busy all the time—these rivers. But although they are always at work they not only never forget to look beautiful but they beautify everything they touch. At the outset the lines of a river valley are rather straight and angular, as if the scenery were just being blocked out by an artist, but as the valley grows older its slopes become more gentle, the angles disappear into rounded forms, and the river itself winds along in graceful lines, exactly reproducing what the great English artist Hogarth called "the line of beauty."

THAT MIGHTY RIVER IN THE MEADOWS

Yon stream, whose sources run,

Turned by a pebble's edge,

Is Athabasca, rolling towards the sun,

Through the cleft mountain ledge.

The slender rill had strayed,

But for the slanting stone,

To evening's ocean, with the tangled braid

Of foam-flecked Oregon.

—Holmes.

Back of all the work of the rivers from year to year and age to age, there seems always the thought of beauty as well as the thought of use. They are evidently under an eternal law of service, of beauty, and of change.

"The hills are shadows, and they flow

From form to form and nothing stands.

They melt like mists the solid lands;

Like clouds they shape themselves and go."

HIDE AND SEEK IN THE LIBRARY

Isn't Tennyson's "Brook" a beautiful title picture of a baby river and its ways?

Speaking of human nature in rivers and apparent differences in disposition, why is it that some of the rivers of California run right through the mountain ranges from east to west—have evidently cut their way—while others run along, meekly enough, between the ranges? I'm sure from what we have learned about rivers that you can tell how this happened as well as if you had been there when the rivers were made; but if you can't think—after trying real hard—you will find the answer in the Hide and Seek at the end of the next chapter.

Beside being so prominent in the literature of the Bible and so famous in history, the River Jordan is a most curious and interesting stream, and every child should know about it. Here are some of the things you will find: Why it is born partly grown, and doesn't begin as a little stream, like the Mississippi; why it may be said to be in both the tropical and temperate zones[13]; about its two valleys, both of which it uses at the same time.[14]

[13] Britannica.

[14] International.

Another famous river over in that part of the world—it's the biggest river in Western Asia, in fact—was born twins. See if you can find such a river on the map. (The name of it is at the end of the next chapter.) In the days of Alexander the Great these twin rivers, which now unite in one after travelling along independently for a while, were a good day's journey apart clear to the end. In the article on this river in the Britannica, and in books of travel you will find how, by a quaint and ingenious device, the river is made to pump itself up hill and irrigate the fields; how history, clear back to the beginning of civilization, is written in the ruins of cities along its banks; how it used to put in part of its time bounding the Roman empire, and how nowadays it is forced to help support Arab river pirates and wild pigs.

Now let's go over into Africa with Doctor Livingstone and see how a river can grind out a big, deep stone jar in solid rock.[15] Rivers grind out these pot-holes much as Indian women and the American pioneers used to grind wheat and corn. (The river, you'll find, uses pebbles for millstones.)

[15] "The Expedition to the Zambesi," page 63. One of these natural water-jars that Doctor Livingstone found was as wide as a well and so deep it kept the water cool even under the broiling African sun.

And what do you think of a waterfall big enough to swallow two Niagaras? (It's the greatest waterfall in the world; so you must have learned its name in your geography.) It's described on page 268 of Doctor Livingstone's book referred to in the foot-note. The natives call it "The Fall of the Thundering Smoke." They wonder how water can smoke, and so that you can see the "smoke" twenty miles away. You'll wonder, too, until you learn the reason.