Читать книгу The Boy with the U. S. Weather Men - Rolt-Wheeler Francis - Страница 10

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The gray morning broke over the desolate scene, and Anton, hollow-eyed and exhausted, looked at the muddy waters rushing savagely over the place where his home had stood. By the tops of the trees, only, was he able to trace the outline of the fields he had known all his boyhood.

"Do you suppose it'll ever dry up, Ross?" he asked.

"Of course it will, Anton," the older lad said, reassuringly, "you'll see. In a week or two all this water'll run off and you'll forget that the old place ever looked like this."

The crippled lad shook his head, as though in doubt.

"My books have gone," he said mournfully.

The tones were quiet, but a tragedy lay beneath the words, and no one knew better than Ross how largely his chum's life lay in the world revealed in his tiny library. The flood would pass away and the fertility of summer would hide every trace of the disaster, but for Anton's loss there was no such swift remedy. His books were his closest friends, and now, at one stroke, he was bereft of all of them.

"Come," said Ross, to change the current of his chum's thoughts, "we'll have to make a start. Where do you suppose your folks are?"

The younger lad turned to his friend with the quick responsiveness and willing resignation often found among those who have suffered a great deal or who are handicapped in Life's race.

"I haven't the least idea," he said, "they might have gone over to the other shore."

"Yes," agreed Ross, thoughtfully, "that's likely. They'd certainly have more chance of finding help and grub over there. And, talking of grub, Anton, aren't you hungry?"

"Starving," admitted the younger lad.

"Then I tell you what, we'd better go and hunt up Levin."

"The chap who used to be with the Weather Bureau, you mean?" Anton asked.

"Yes."

"Don't you think that I ought to try to find Father first?" queried the younger lad, hesitatingly. "He might be worrying."

"It's because of your folks that I think we ought to go first to the camp," explained Ross. "We couldn't possibly row right across the flood to the other shore. We've had trouble enough getting as far as this. Besides, Anton, even if we did get over, we wouldn't know where to look for your people. There's a chance that Levin may have heard from them, and if he hasn't, he might send some one with a message. We couldn't do much searching, anyway."

In truth, the boys were utterly exhausted. The only member of the party who seemed in high spirits was Rex. He frisked about and jumped on the two boys, his tail sticking straight up in the air, as though he were convinced that it was solely through his exertions that Lassie and the puppies had been rescued.

Ross slung the basket, with its living freight, across his shoulders and started off. Lassie watched this elevation of her children with manifest uneasiness, but as her master seemed satisfied, there was nothing for her to do but to follow behind, which she did with her nose as close to the basket as possible.

Nerve-frazzled and tired out, Anton pegged away behind. The heavy downpour of rain, which had not ceased for a day and a night, and which had followed upon the heavy rains of the week before, had made the ground as soft as a bog. The crippled lad's crutch sank in so deeply at every step that it was only with great pain that he could keep up at all. Still, he struggled along bravely.

Ross, turning to see how his chum was faring, caught the boy's tense and haggard look, and understood.

"Look here, Anton," he said, at once, "we'll never get anywhere this way. You get into the boat and I'll tow you."

"But you can't, you're just about all in," protested the younger boy. "You can't tow the boat with me in it, all the way."

"Got to!" declared Ross abruptly. "It's a sure thing that you're not able to walk there with the ground in this sodden condition. Anyway, I won't have to carry the puppies."

Thankful but still protesting, Anton got into the boat and the journey began anew.

It was a weary way. Ross staggered forward, half-blind with sleep, wading knee-deep, sometimes waist-deep, in the water. The rain had stopped, but the sky was heavy and the clouds hung low. Twice Anton had to jerk on the tow-rope to jolt Ross awake, for, unnoticing, he was heading for deep water. Even near the shore the torrent was full of floating debris. The bodies of horses and cattle drifting down the stream told of many impoverished farms and the flotsam was eloquent of wrecked and demolished houses and indicative of suffering.

The Edge of a Tornado's Whirl.

Note the house in the background unharmed, and the house next to it spun around like a top.

Courtesy of U. S. Weather Bureau.

When, after an hour's toil, rescuer and rescued reached the drier land that sloped up to the levee, it was hard to tell which was the more exhausted. To the last, however, Ross refused to let his chum bear the burden of the puppies, and he lurched up the road to the place where he had left the gang at work on the cave-in, not so many hours before. It seemed weeks ago.

The Weather Man was still at work. He had been up all night, also, but he greeted the lad cheerily as he came in sight.

"Hello, Boss!" he called, then, as the boy's exhausted state became more evident, "what have you been doing? Has anything happened?"

"Anton was marooned," answered Ross in the dull, listless voice of extreme fatigue.

"Marooned? You mean he was caught by the flood?"

As though in answer, Anton, toiling heavily and wearily on his crutch, came in sight.

"Yes," said Ross, in the same tone, "he was left behind."

"How was that?" the Weather Man asked sharply.

"It wasn't anybody's fault, Mr. Levin," replied Anton, who had heard the last two sentences as he came up, "Father thought I'd gone with Uncle Jack, and Uncle Jack thought I'd gone with Father."

"You're not hurt?"

"No, sir," the crippled lad answered, "not a bit. Ross is, though. He cut his arm diving through the window."

The Forecaster turned swiftly to the older boy and began examining the injury.

"Is the house still standing?" he asked.

"No, sir," the boy answered, "it's all in bits down by Jackson's Gully."

The weather expert nodded. He knew the lay of the land and had expected the water from the flooded hollow to pour down towards the entrance to the gully.

"How did you get out, then?" he asked.

Anton burst into a glowing account of his rescue in the little boat which the boys had made for their pirate adventures of two years before. Even the excitement of the story, however, was not strong enough to keep his overtaxed frame from showing signs of a breakdown and the Weather Man cut the story short.

"I'm going to breakfast later," he said curtly, "but not for a couple of hours. You two had better take a rest now. Here, Sam," he called to one of the negroes, "bring me a bucket of coffee from your camp-kettle, and fetch some corn-pone. Quick now, these boys are famished."

"Yas, suh! Yas, suh!" came the reply, and, a moment later, a bucket of coffee and some corn-bread and molasses were brought.

Despite their hunger, neither Ross nor Anton could eat more than a few mouthfuls, and the hot drink was the last straw to their sleepiness. Ross fell asleep with an unfinished piece of corn-pone in his hand, and Anton's head was nodding.

"Ain' no more weight than a babby, Mister Levin," said the laborer, as he picked up the little crippled lad and carried him to a tiny open shed near by, which was the only dry spot to be found in the neighborhood.

Very tenderly he laid the boy down on a pile of clothes that had been salvaged while the Forecaster put his overcoat over Ross and laid him beside his chum.

"There," said the Weather Man, "let them sleep a while. They'll be ready for a real breakfast in a couple of hours."

Though hungry himself, the Forecaster waited for three hours before awakening the lads. Anton, by nature a light sleeper, awoke easily and was refreshed, but the awakening of Ross was a real task. He had been on a severe strain for twenty-seven hours and Nature demanded sleep. At last, however, he was roused and after he had plunged his head in a pail of cold water, he felt as full of ginger as ever and ready to start on rescue work all over again.

"I'm just going to breakfast," the Forecaster announced. "Do you want to go along?"

"Do I? I should say I did! But I'm afraid, sir, that Anton and I will eat up everything in sight."

"You don't need to worry about that," the Forecaster replied, "my men have been hauling supplies all night. Why, Ross, there are over two thousand people homeless this morning, right around this district. They've all got to eat breakfast, too, so you see even your best efforts won't seriously decrease the supply."

"I'm not so sure about that, sir," Ross said laughing, "right now I feel as though I could eat all you've gathered for the entire two thousand."

"Come and try, then," the Weather Man said, smiling. Then, turning to Anton, he continued, "Likely enough, some of your people will be at the big tent that's been put up. If they're not there, I'll send out a couple of the boys on horseback to cover both sides of the flooded area and pass the word that you're safe." He turned to the older boy. "I've already sent word to your father, Ross."

The boys thanked him and started down the levee. Owing to the continuous work of the night, the cave-in had gradually been filled up, averting a break at this point. The river, turbid and swollen, was swirling by, not more than three feet below the top of the levee.

"Is the water going down yet, Mr. Levin?" asked Ross. "It looks as though the rain were over."

"Yes," answered the Forecaster, "the rain is over, but the water's not going down yet. It's rising. I'm fairly sure that there won't be any more rain for a few days, fortunately, but I heard from Greenville this morning that the river was still rising. We can stand another nine or ten inches, but a foot would be serious. Of course, the break that flooded out Jackson's Hollow, where your place was, Anton, is relieving the pressure a little. We've been lucky here. I haven't heard of any loss of life so far. It's a nasty flood, but when the rainfall last week was reported as being so heavy, I knew we couldn't escape trouble."

"Is it just the rain that makes floods?" Anton asked.

"Just rain," was the laconic answer.

"Why is it," asked the younger boy, "that there's more rain one year than another?"

"If I could tell you that," the old Weather Forecaster replied, "I'd be the cleverest meteorologist in the world."

"But doesn't anybody know why it rains?"

"Certainly, we know why it rains."

"Why, Mr. Levin?"

The Forecaster pushed back his hat from his forehead and looked quizzically at the white-faced lad.

"You really want to know why rain comes? Very well, Anton, I'll try to tell you. Stop me, though, if you don't quite understand.

"The Earth goes whirling about in space, revolving around the Sun, as you know, and it has, like a sort of skin around it, an envelope of air. This air is kept from flying off by the force of gravity. You know what that is?"

"Yes, sir," the cripple answered, "it's what makes a stone fall to the ground."

"Exactly. Now the air is made up of little particles or molecules, like the stone, only, of course, not so heavy. They're heavy enough, though. How much weight of air do you suppose you're carrying, Anton?"

The boy looked puzzled.

"I don't quite see what you mean, sir," he answered.

"Suppose you had a pea on your head, it wouldn't be heavy to carry, would it?"

"Why, no," answered the lad, laughing.

"Supposing you had a basket of peas, the basket being only about as big round as your head, but six feet high, that would make quite a load, wouldn't it?"

"I don't believe I could carry it," was the answer.

"And if the basket were sixty feet high, as high as a barn?"

"I'd be squashed under it."

"And if it were six miles high!"

"Why," answered Anton, "a basket six miles high, even if you filled it up with cotton fluff, would weigh tons and tons!"

"Well, my boy," said the Weather Forecaster, "you're carrying on the top of your head a column of air, not only six, but sixty miles high, yes, and more than that! You don't notice it, of course, because you're used to it, and your body is made to accommodate itself to that weight by your tissues being full of air at the same pressure. Just the same, not counting the weight which presses on your whole body, amounting to about seventeen tons, you're carrying on your head, at this minute, a weight of over six hundred pounds."

"Six hundred pounds! As much as if I were carrying three heavy men sitting on my head!"

"Every bit of it, and more, under certain conditions of the atmosphere. This depends mainly on the circulation of the winds, especially those great movements a thousand miles in diameter known as 'lows' and 'highs' or cyclones and anti-cyclones. In the United States, an anti-cyclone generally means fair weather, and in an anti-cyclone the barometric column rises. That's why a barometer helps to foretell weather some time in advance; it responds to the vast movements of the atmosphere rather than to local conditions.

"Of course, Anton, at sixty miles up, the air is so thin that it has hardly any weight. Indeed, we wouldn't know there was any air at that height but for the trail that shooting stars leave. A meteor glows because of friction, and in a vacuum there is no friction. Therefore there must be air at the vast heights where shooting stars are first seen."

"Could an aeroplane get up there?"

The Forecaster shook his head.

"Never," he answered. "Even six miles up, the air would be too thin to sustain the weight of an aeroplane unless the machine were flying at terrific velocity, and besides, at that height, there wouldn't be enough air for an aviator to breathe. At that, Anton, you can see for yourself that if the air is saturated with water vapor—and the cloud-bearing atmosphere is eight or ten miles thick—there is room for a lot of water."

"It's evaporation that puts water into the air, isn't it, sir?" asked Ross.

In the Path of the Lightning.

Courtesy of U.S. Weather Bureau.

In the Path of the Tornado.

A farm-house, with farm buildings in a copse of trees stood here; the buggy, after a flight through the air, was dropped, little injured.

Courtesy of T. B. Jennings, U. S. Weather Bureau, Topeka, Kans.

"Exactly. The sun is shining on some part of the earth all the time. There's never a second, day or night, that water is not being evaporated from the seas, from lakes, from rivers and from the earth itself. All the water that is taken up must fall somewhere, and all the rain that falls means that the atmosphere must fill itself with water vapor again. It's a continuous performance, and the water which is being evaporated into the air falls to the earth, sooner or later, as rain, hail, or snow."

"If it's all so regular," said Anton thoughtfully, "I don't see why we don't get the same amount of rain every day, or at least every season."

"It isn't regular at all," the Weather Forecaster explained. "If climatic conditions were regular, we could forecast the weather several years in advance, instead of only a few days. There are a thousand complicating factors. Land and sea are irregularly divided, and as there is more evaporation from the sea than the land, every little curve in a coast line means a disturbance of regularity. Then, Anton, remember, while the earth is almost a globe it is not perfectly round, so that every variation from the regular curve disturbs the air currents. Moreover, the motions of the earth are very complicated. Sometimes it is nearer the sun than at other times. It wobbles slightly on its axis. It is inclined to the plane of the ecliptic, causing the seasons, and that brings a new set of factors into the problem. A mountain range or a desert will modify the atmosphere, even the difference between a forest and a prairie is noticeable."

"Suppose you could figure all those things out, couldn't you foretell the weather, then?"

The Forecaster shook his head.

"Suppose you had a thousand marbles of different colors," he said, "and you dropped them from the top of a house to the hard ground below, a rough and rocky piece of ground, could you ever figure out what kind of a pattern they would make? You might measure the size of the marbles and compute how many times they would strike against each other in falling, meantime figuring the angles of direction that each collision would produce. You might measure the resistance of the ground and the elasticity of the marbles and estimate the manner in which they would bounce after striking the ground and the distance to which they would roll. After you had done all that, you might have the right to expect that you would know the pattern that the marbles would make as they lay scattered on the ground. But you would be wrong, for if you dropped those marbles a thousand, yes, a million times, the pattern would be different each time. After tens of billions of experiments you might be able to find the proportion of patterns, but the result would never be of practical use.

"It's the same way with the weather. We know well enough how to do the things that would enable us to prophesy a long time in advance what the weather is going to be, but the problem approaches impossibility because there are too many factors that enter into the calculation. We're learning all the time, but it's a big piece of work and needs big men to do it. That's why, Anton, I can't tell you why this particular district had more rain this year than it has had for several seasons past."

Anton, pegging away on his crutch beside the Forecaster, looked up at him with an added eagerness in his eyes.

"And yet all those things are going on, right where I can see them!" he exclaimed.

"Yes," the Weather Man answered. "Some men can explore distant countries, and we envy them; some men can explore the greatest and the smallest things in the world with marvellous scientific instruments and we envy them, too; but every day and all day, and every night and all night, we are surrounded by the World of the Weather, less explored, less known than even the most remote corner of the earth. Why, Anton, if you could simply follow all the various causes that brought about this flood that made you homeless, you would have a story of adventure that would make the most daring explorer green with envy."

"But you do predict floods and rains, Mr. Levin," Ross put in. "Father told me, a week ago, that warnings for this flood had been sent out by the Weather Bureau."

"Yes, indeed," the Weather Man answered. "I should say that weather warnings issued by the Bureau save half a billion dollars to the country every year and prevent the loss of hundreds of lives. All those are short-range predictions. Very few of them cover much more than a week in advance, except, perhaps, a West Indian Hurricane which has been reported from the Antilles, or a flood on the Mississippi which is caused by heavy rains in the upper reaches of the streams flowing into it."

"Well, that's prophesying, isn't it?"

"Yes, and no," was the reply. "It's predicting, and it's due to observation. If a storm is moving eastward, with a heavy rainfall, and we've had telegraphic dispatches from all the towns in the west through which it has passed, it's not hard to figure the speed at which the storm is traveling, and it's a sure prediction to tell a city to the eastward of that storm that rain can be expected at about a certain date. Or, if there's a high flood wave at St. Louis, and we know the speed of the Mississippi current, we can notify Greenville, Vicksburg, and New Orleans at what time the trouble is likely to come to them. If no more rain is falling at Greenville and the river is going down there, we can notify Vicksburg that the flood danger is passing away. That's the observational end of the work, and in that line, the Weather Bureau of the United States is the best in the world."

The weather expert was proceeding to explain in detail the manner of collecting these observations, when suddenly Anton clutched him by the arm.

"What's that, Mr. Levin?" he cried.

The Forecaster looked ahead, then glanced down at the boy with a smile.

"What does it look like?" he asked.

"Why," said Anton, "it looks like a circus tent; you know, the one that was here the week before last."

"It is the circus tent," the Forecaster replied. "When I found that there were a couple of thousand people to be fed and looked after, the only shelter I could think of, that was big enough, was the circus tent. So, late last night, I sent a wagon up there, asking for the loan of the tent for a day or two. And what do you suppose the circus folk did?"

"Sent it?"

"They sent it, with two of their wagons, a lot of food, their cooking kit, and the two cooks who travel with the circus. What's more, Anton, you remember those two clowns in the show who were so funny?"

"You bet I do!" exclaimed the lad, his eyes shining.

"They volunteered to come down and help as waiters. They're doing it, too, and it's a right good thing, for every one around in the place is roaring with laughter half the time. Folks work a lot better when they're cheerful."

A perfect gale of merriment, which greeted the boys as they neared the tent, showed the truth of the Forecaster's statement. He had greatly understated the work of the circus. Nearly all the performers were there, busily helping the distressed.

"They're a right kindly folk, the circus people, as a rule," remarked the Forecaster.

"Are they all here?" queried Anton. "Goliath, the strong man, the Flying Squirrel Brothers, Androcles, the lion tamer, Princess Tiny and the rest?"

"Yes, most of them," the Forecaster answered. "Goliath is in charge of one of the gangs I've got at work on the river front, and the darkies are so proud of being under him that they're working like fury. The Flying Squirrel Brothers—cracker-jack mechanics, both of them—have been fixing up some tackle and machinery that we needed, but I think Androcles stayed back with his lions. I suppose he thought the lions wouldn't do us any good. But if you're not too hungry to wait just for a second—"

He paused.

"What?" queried Anton excitedly.

"Yes, there they are!" the Forecaster answered, gazing along the levee.

Both boys followed his glance.

Vast, bulky shadows stood outlined against the distant Arkansas shore and the clearing sky. Unreal they seemed, until it was evident that they were moving.

There, shuffling along with that heavy rolling gait which is unlike that of any other animal in the world, came two colossal elephants.

Anton shrieked with delight.

"Elephants! Real elephants!" he cried. "Oh, Mr. Levin, I haven't ever seen an elephant quite close."

He started off up the levee, but the Forecaster called him back.

"Have your breakfast first, Anton," he said; "you've got all day to look at the elephants. They're the best workers I've got. I'd like to have a gang of them at work on the levee all the time."

This sentiment was not shared by Rex. At the first sight of the huge creatures, Lassie had given a low growl. Rex stood silent, with a stillness that Ross knew to be ominous, and just as the Forecaster finished speaking, with an angry growl, he started off to do battle against the elephants. It was a sight to see him, with his hair bristling, rushing forward to dispute the passage of these huge brutes who dared to approach the vicinity of Lassie and the puppies. Only the sharp commands of Ross availed to bring him back, and throughout breakfast he lay well in advance of the tent, watching, and growling loudly every time the elephants passed, dragging the flat sleds loaded with sand bags to the cave-in a few hundred yards beyond.

"I've been wondering," began Anton, using the expression most often on his lips, "why there are so many floods on the Mississippi. Why is it? Lots of rivers I know don't have these awful floods every year."

"I've wondered, too," said Ross.

The Weather Man looked at the two boys, then took a cigar out of his pocket.

"I can't stay away from the levee very long," he said, "but I need a cigar after breakfast, anyway, and I'll tell you why the Mississippi is one of the worst flood rivers in the world and why the safeguarding of the Mississippi is the biggest piece of work to be done in the United States. It's a bigger piece of work than the Panama Canal, and a more difficult piece of work. It means millions of dollars every year to the people of the United States."

"Why is it such a hard job?"

"The Mississippi River," the Forecaster began, "is two and a half thousand miles in length; the longest river in the world."

"Longer than the Amazon?" asked Anton.

"Yes, a great deal. Besides, it is navigable for nearly two thousand miles, clear from St. Paul, Minnesota, to the Gulf. It drains two-fifths of the area of the United States. To put it another way, all the rain and snow that falls between New York State and Montana sooner or later makes its way into the Mississippi River, except for the rain that is used up by plants and animals or that is evaporated before it reaches the river or that drains by underground seepage to the ocean. So you see what a vast amount of water it must carry. Now, boys," he continued, "what kind of banks has the river around here, rock or earth?"

"Mud!" answered Ross, tersely.

"Right," the Forecaster agreed, "and it is mud nearly all the way along. But do you know what mud is?"

FACING A CLIMB ON SHOW-SHOES.	TWENTY-FIVE FOOT DRIFT A MILE LONG.
FOREST RANGER IN IDAHO.	OBSERVER AMONG THE QUAKING ASPENS.
Snow Survey work. Courtesy of U. S. Weather Bureau and of J. Cecil Alter.

This was rather a poser, but finally Anton said slowly,

"It's a mixture of earth and water, isn't it?"

The Forecaster looked shrewdly at the boy.

"You've hit it just right," he said, "mud is earth or soil that has been washed down by the river. That's what makes the bottom of the river so irregular and why it's always shifting. You can see for yourselves, boys, that if the bottom of the Mississippi is just made of light mud, light enough to be carried down as muddy water for hundreds of miles, any little change in the current of the river will stir up that mud again and scoop out a hole. If it happens to be near a bank, the bank will be eaten away and, naturally, will cave right in."

"About how much mud does the Mississippi carry down, Mr. Levin?" Anton asked.

"In flood time, as much as a thousand tons a minute will be carried past here."

Ross whistled.

"A thousand tons a minute!" he exclaimed. "Why, I should think that would fill up the river in no time."

"It would," the Weather Man answered, "if the river stood still. In flood time, however, the water is flowing rapidly and takes the mud clear down to the delta. That's why there is always so much new land being made at the mouth of the river. You could buy a piece of land under water now, Ross, if you wanted, and be quite sure that in twenty years' time there would be land there for a farm."

"But a thousand tons a minute!" the boy repeated, "that seems huge!"

"It is pretty big," the Forecaster agreed, "but I'll show you where it comes from. You know, boys, generally the land slopes down in the direction of the river, doesn't it?"

"Yes," assented the two boys, "it's supposed to. But it doesn't here. The lie of the land is away from the river."

"That's just exactly the point," the Forecaster declared. "The banks of the Mississippi range in height from about twenty to forty feet above extreme low water. As the river, in times of flood, rises as high as forty to fifty feet above low water, unless there were levees, the river would overflow its banks every spring or flood time."

"It does, quite often, even yet," commented Ross, looking on the flooded scene around him.

"Well," said the Weather Man, "the present levee system only dates back to the end of the Civil War, although there were levees built during the first settlement of New Orleans, two centuries ago. Remember, though, that the Mississippi has been flowing down its present bed for several hundred thousand years, with a flood every spring, so that the overflow has had its effect. Of course, before the land was broken up by farming, there wasn't as much earth carried down into the river to make mud as there is now.

"When the Mississippi River, with its heavy sediment, overflows the banks into the swamps, it's easy to see that the current will be slower in the flooded area than in the main bed of the river."

"Of course," agreed Ross, "but what has that got to do with it?"

"A great deal," the Forecaster replied succinctly. "The faster a river flows, the more sediment it can carry without allowing it to drop to the bottom; the slower it flows, the more readily is the sediment dropped. If you put some mud in a glass of water and keep stirring it with a spoon, the mud will never sink to the bottom. Even if you let it stand perfectly still, it will take several days before the finest particles sink to the bottom of the glass and the water becomes clear."

"Yes," agreed Anton, "I've often wondered why."

"Well," the Weather Man continued, "if you look closely at the mud in the bottom of the glass, you'll see that the bigger particles are at the bottom and then those a little smaller and so on up, until your top layer is made of a mud composed of particles so fine that you'd have to get a microscope to see them."

"I don't quite see why," said Ross. "I know bigger things are heavier, but why should a big bit of earth sink more quickly than a small bit, when they're both made of just exactly the same stuff?"

The Weather Man looked at him.

"Some of these days," he said, "remind me to talk to you about sunlight and dust, and I'll tell you a heap of things you don't know. Right now, get this idea in your head. The larger a piece of matter is, the smaller is the surface in proportion to the bulk. A feather of swan's down will float in a high wind, but if you roll that feather into a ball, it will fall. Why? You haven't made it any heavier. You've only reduced the amount of surface which was borne up by the air. It's the same way with mud, the bigger pieces sink first because they have less surface in proportion to their weight."

"Yes," answered Ross, "I can see that now."

"Very good, then," the Forecaster continued, "when the Mississippi overflowed its banks and the water got out of the current of the main stream, so that it flowed more gently, the sediment began to fall, the larger pieces first and those that were finer until it was only at the most distant point from the river that the finest mud settled. This has gone on, year after year, for thousands of years.

"Therefore, you see, the lands nearest the river are higher than those farther away. In two big basins, the St. Francis and the Yazoo basins, the slope and the drainage is away from the river, instead of towards it."

"In that case, then," said Anton thoughtfully, "the Mississippi runs in a groove on the top of a hill."

"That's it exactly," the Forecaster said, "and some of the most fertile fields lie in the lowlands made of the fine mud at the bottom of this hill. It's just like that hollow where your house was, Anton. The flood hasn't done much damage south of here because all the waters poured down into that fine plantation land where your place was located."

"What I don't see," said Ross, "is why the Government doesn't build a really high levee all the way along the river. I don't mean just a few feet higher, but a regular wall 'way higher than the river ever goes. I mean a regular stone wall, twice as high as any levee that we've got now. I should think that would make the river behave."

"It would and it wouldn't," replied the Weather Man. "What are you going to build that wall on? On the ground?"

"I suppose so," said Ross. "I hadn't thought much about that."

"Indeed you hadn't," his friend replied. "You've got to remember, Ross, that the Mississippi doesn't run in a straight line; it bends and twists like a snake. In the bends the current strikes on the outwardly curving bank, and, as you know, the water is always deep there. This causes a rapid caving and erosion of the bank. At the foot of each bend, the main flow crosses to the other side, where it strikes the bank which has become concave there, and eats into that bank just as, a few hundred yards higher, it has been eating into the opposite one."

"I know you've always got to pilot a boat first on one side of the river and then on the other," said Ross thoughtfully.

"You have. And, if you remember, you'll see that it is generally on the side nearest to the concave shore that the boats pass."

"Yes," agreed Ross thoughtfully, "I guess it is."

"Now, you can easily see," the Forecaster continued, "that the river might keep its own channel clean if it flowed straight down with a current of equal strength. But, as the current crosses from side to side, it slackens speed at each of these crossings. Therefore, as the current becomes slower, it drops some of the heavier particles of sand or mud, forming a bar at every bend, sometimes so high as to prevent navigation."

"That's what the dredges are for, isn't it?" asked Ross.

"Yes. The Government has twelve large dredges at work all the time, keeping the navigation channel open."

"I don't see, yet, why the stone wall idea wouldn't work," protested Ross.

"I'm just showing you," was the reply. "If you built your heavy wall on the bank, the water would strike the concave bank at one of these crossings, eat away the earth under the wall and your wall would topple in. Then the current would cross the stream, undermine the bank on the other side and your masonry would crumble there, too. So much for the wall."

"Suppose you sunk that wall, away down deep, below the level of the bottom of the river?" suggested Ross.

"That might work," the expert replied, "but it would cost more money than the United States could afford to spend. Besides, Ross, where would you build this wall? Right on the bank?"

"Of course."

"But the Mississippi is half a mile wide at some places and three miles wide at others. If the river were absolutely walled in, you'd have swift currents at one place and slow in another. Then your channel would fill up in the wide places and you'd be as badly off as before."

"Make it all the same width, then," said Ross.

"Build two-thirds of the whole two thousand miles by some underwater system, constructing the wall under water? If you had ever read of the difficulty of building one lighthouse foundation, my boy, you wouldn't talk so glibly about building huge retaining masses of masonry under water."

"Suppose it were done, that way, Mr. Levin," put in Anton, "would that settle it all?"

"You mean—suppose there was a high masonry wall, making a canal equal in width and height from St. Louis to the Gulf, would that turn the Mississippi into a permanent ship channel? Is that what you mean?"

"Yes."

"No, it wouldn't," the expert replied. "What are you going to do with all the little streams that flow into the Mississippi? Think for a minute, boys. You can see that wherever you narrow the banks, the river channel has got to be made deeper to accommodate the water, hasn't it?"

"Yes," both boys agreed, "it has."

"In other words, suppose that before you put up this huge masonry wall, the flood crest was fifty feet at Memphis, then, after the wall was built, the flood crest would be seventy-five or a hundred."

"Suppose it were," said Ross, "the wall would hold it in."

"So you think. There are the tributaries to consider. Take the Yazoo, for example. It flows into the main river until the Mississippi reaches the fifty-foot flood level. If you raise the flood level of the Mississippi to seventy-five feet, the water in the main river will be twenty-five feet higher than the water which used to run into it at the fifty-foot level, won't it?"

Ross whistled.

"I see where you're coming to," he said; "I'd never have thought of that. Go ahead, Mr. Levin."

"With the water in the main stream twenty-five feet higher than in the tributary, due to your retaining wall, boy, instead of the water in the Yazoo River flowing into the Mississippi, all the water above the fifty-foot level in the Mississippi would flow into the Yazoo. The Yazoo couldn't hold the water, and as the stream backed up, it would overflow its banks. All the low valleys would be flooded in exactly the same way that they were before, only, instead of the floods coming directly through a break in the levee or over the banks of the Mississippi, they would come over the banks of the Yazoo. That would be true of every small river that flows into the Mississippi, and there are scores of them."

"What can be done, Mr. Levin?"

"There's only one thing to do," the Weather Man answered, "and that's to build up the levee system, year after year, steadily and without pause, making allowances for the tributaries flowing into the Mississippi and paying especial heed to the rainfall that may be expected in the basin. Wherever possible, forestry must be undertaken to keep the slopes from erosion. Reservoirs might be built with great profit, from which water could be let down during the low water periods.

"When the river channels are accurately adjusted to the amount of rainfall in the river basin, destructive floods will be averted. We can never expect that the Mississippi will be absolutely put in harness. The basin is too huge, the amount of water that has to be carried down is too great. Permanent dredging and permanent levee construction and repair will always be necessary, and a close co-ordination between the Weather Bureau and the government and state engineers is a first need in the problem."

"Just how does the Weather Bureau come in," asked Ross, "the rainfall?"

"It isn't only the rainfall of the few days in advance," the Forecaster answered, "it's the rain that has fallen before and the rain that's going to fall. If there should be twelve inches of rainfall after a long drought throughout the Mississippi basin, it would make comparatively little difference, for all the rain that fell on the dry ground would be sucked up by it and only a very little would flow into the rivers and streams that feed the Mississippi.

"On the other hand, if there had been slight but frequent rains for weeks and weeks, those twelve inches of water would make an entirely different story. No one, except the Weather Bureau, would have kept track of the amount of rain that had fallen.

"If the ground has been steadily soaked, even by light occasional showers, twelve inches more of rain cannot soak in. Therefore, the entire amount of rain will flow directly into the stream channels and thus into the Mississippi. Flood warnings will be sent out, the height of the flood crest can be estimated, the length of the period of the danger will be known in advance and the proper preparations can be made. If further rain is threatened, that information can be sent out, also, and the entire Mississippi valley is completely prepared. That's the true preparedness, my boy, being ready for the foe that you know will come. Stupidity or cowardice are the only causes for not being willing and ready to help in time of danger."