Madam How and Lady Why; Or, First Lessons in Earth Lore for Children. Charles Kingsley

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СКАЧАТЬ there is a law for every sort of motion) it is that the earthquake shock sometimes hurls great rocks off a cliff into the valley below.  The shock runs through the mountain till it comes to the cliff at the end of it; and then the face of the cliff, if it be at all loose, flies off into the air.  You may see the very same thing happen, if you will put marbles or billiard-balls in a row touching each other, and strike the one nearest you smartly in the line of the row.  All the balls stand still, except the last one, and that flies off.  The shock, like the earthquake shock, has run through them all; but only the end one, which had nothing beyond it but soft air, has been moved; and when you grow old, and learn mathematics, you will know the law of motion according to which that happens, and learn to apply what the billiard-balls have taught you, to explain the wonders of an earthquake.  For in this case, as in so many more, you must watch Madam How at work on little and common things, to find out how she works in great and rare ones.  That is why Solomon says that “a fool’s eyes are in the ends of the earth,” because he is always looking out for strange things which he has not seen, and which he could not understand if he saw; instead of looking at the petty commonplace matters which are about his feet all day long, and getting from them sound knowledge, and the art of getting more sound knowledge still.

      Another terrible destruction which the earthquake brings, when it is close to the seaside, is the wash of a great sea wave, such as swept in last year upon the island of St. Thomas, in the West Indies; such as swept in upon the coast of Peru this year.  The sea moans, and sinks back, leaving the shore dry; and then comes in from the offing a mighty wall of water, as high as, or higher than, many a tall house; sweeps far inland, washing away quays and houses, and carrying great ships in with it; and then sweeps back again, leaving the ships high and dry, as ships were left in Peru this year.

      Now, how is that wave made?  Let us think.  Perhaps in many ways.  But two of them I will tell you as simply as I can, because they seem the most likely, and probably the most common.

      Suppose, as the earthquake shock ran on, making the earth under the sea heave and fall in long earth-waves, the sea-bottom sank down.  Then the water on it would sink down too, and leave the shore dry; till the sea-bottom rose again, and hurled the water up again against the land.  This is one way of explaining it, and it may be true.  For certain it is, that earthquakes do move the bottom of the sea; and certain, too, that they move the water of the sea also, and with tremendous force.  For ships at sea during an earthquake feel such a blow from it (though it does them no harm) that the sailors often rush upon deck fancying that they have struck upon a rock; and the force which could give a ship, floating in water, such a blow as that, would be strong enough to hurl thousands of tons of water up the beach, and on to the land.

      But there is another way of accounting for this great sea wave, which I fancy comes true sometimes.

      Suppose you put an empty india-rubber ball into water, and then blow into it through a pipe.  Of course, you know, as the ball filled, the upper side of it would rise out of the water.  Now, suppose there were a party of little ants moving about upon that ball, and fancying it a great island, or perhaps the whole world—what would they think of the ball’s filling and growing bigger?

      If they could see the sides of the basin or tub in which the ball was, and were sure that they did not move, then they would soon judge by them that they themselves were moving, and that the ball was rising out of the water.  But if the ants were so short-sighted that they could not see the sides of the basin, they would be apt to make a mistake, because they would then be like men on an island out of sight of any other land.  Then it would be impossible further to tell whether they were moving up, or whether the water was moving down; whether their ball was rising out of the water, or the water was sinking away from the ball.  They would probably say, “The water is sinking and leaving the ball dry.”

      Do you understand that?  Then think what would happen if you pricked a hole in the ball.  The air inside would come hissing out, and the ball would sink again into the water.  But the ants would probably fancy the very opposite.  Their little heads would be full of the notion that the ball was solid and could not move, just as our heads are full of the notion that the earth is solid and cannot move; and they would say, “Ah! here is the water rising again.”  Just so, I believe, when the sea seems to ebb away during the earthquake, the land is really being raised out of the sea, hundreds of miles of coast, perhaps, or a whole island, at once, by the force of the steam and gas imprisoned under the ground.  That steam stretches and strains the solid rocks below, till they can bear no more, and snap, and crack, with frightful roar and clang; then out of holes and chasms in the ground rush steam, gases—often foul and poisonous ones—hot water, mud, flame, strange stones—all signs that the great boiler down below has burst at last.

      Then the strain is eased.  The earth sinks together again, as the ball did when it was pricked; and sinks lower, perhaps, than it was before: and back rushes the sea, which the earth had thrust away while it rose, and sweeps in, destroying all before it.

      Of course, there is a great deal more to be said about all this: but I have no time to tell you now.  You will read it, I hope, for yourselves when you grow up, in the writings of far wiser men than I.  Or perhaps you may feel for yourselves in foreign lands the actual shock of a great earthquake, or see its work fresh done around you.  And if ever that happens, and you be preserved during the danger, you will learn for yourself, I trust, more about earthquakes than I can teach you, if you will only bear in mind the simple general rules for understanding the “how” of them which I have given you here.

      But you do not seem satisfied yet?  What is it that you want to know?

      Oh!  There was an earthquake here in England the other night, while you were asleep; and that seems to you too near to be pleasant.  Will there ever be earthquakes in England which will throw houses down, and bury people in the ruins?

      My dear child, I think you may set your heart at rest upon that point.  As far as the history of England goes back, and that is more than a thousand years, there is no account of any earthquake which has done any serious damage, or killed, I believe, a single human being.  The little earthquakes which are sometimes felt in England run generally up one line of country, from Devonshire through Wales, and up the Severn valley into Cheshire and Lancashire, and the south-west of Scotland; and they are felt more smartly there, I believe, because the rocks are harder there than here, and more tossed about by earthquakes which happened ages and ages ago, long before man lived on the earth.  I will show you the work of these earthquakes some day, in the tilting and twisting of the layers of rock, and in the cracks (faults, as they are called) which run through them in different directions.  I showed you some once, if you recollect, in the chalk cliff at Ramsgate—two set of cracks, sloping opposite ways, which I told you were made by two separate sets of earthquakes, long, long ago, perhaps while the chalk was still at the bottom of a deep sea.  But even in the rocky parts of England the earthquake-force seems to have all but died out.  Perhaps the crust of the earth has become too thick and solid there to be much shaken by the gases and steam below.  In this eastern part of England, meanwhile, there is but little chance that an earthquake will ever do much harm, because the ground here, for thousands of feet down, is not hard and rocky, but soft—sands, clays, chalk, and sands again; clays, soft limestones, and clays again—which all act as buffers to deaden the earthquake shocks, and deaden too the earthquake noise.

      And how?

      Put your ear to one end of a soft bolster, and let some one hit the other end.  You will hear hardly any noise, and will not feel the blow at all.  Put your ear to one end of a hard piece of wood, and let some one hit the other.  You will hear a smart tap; and perhaps feel a smart tap, too.  When you are older, and learn the laws of sound, and of motion among the particles of bodies, you will know why.  Meanwhile you may comfort yourself with the thought that Madam How has (doubtless by command of Lady Why) prepared a safe soft bed for this good people of Britain—not that they may lie and sleep on it, but work and till, plant and build and manufacture, and thrive in peace and comfort, we will trust СКАЧАТЬ