CHAPTER XV.
THE BOYS ARE DRIVEN OUT OF THE ROOT FORTRESS.
Sam was only partially conscious during the battle around hishabitation. The fever, which now rose and fell at intervals, was usuallyhighest during the forenoon, abating somewhat later in the day. When itwas highest he was always in either an unconscious stupor, or a wilddelirium. When the fever abated, however, his consciousness returned,and he was capable of talking and of understanding all that was said. Inthese lucid intervals, he insisted upon knowing all that had happened,so that he might tell the boys what was best to do. On this day Tom hada story of more than ordinary interest to tell him, about the battle andthe chance of rescue which had so narrowly passed them. Sam wasinterested in it all as a matter of course, but he was still moredeeply interested, it seemed, in the condition of the sand near theplace where he was lying. He had dug a little hole with his hand, andfeeling of the sand found it decidedly wet. Turning to Tom, he said:
"The river is rising rapidly, isn't it?"
"Yes; but how did you find it out?"
"By the sand. I've been watching it a good deal since the fall rains setin, as I'm afraid the river will drive us out of here. You see, thewater works easily through the sand, and you can always tell what thelevel of the river is, if its banks are sandy, by digging down to wherethe sand is wet."
"Yes," said Tom, "but the river isn't within a hundred feet of us yet."
"You are mistaken. It is within six inches of us," said Sam.
"How's that?"
"Well, this bank is almost exactly level, and when the river gets aboveits edge it spreads at once all over it. Now the sand is wet within sixinches of the top, and the river is within six inches of the edge of thebank. When it rises six or eight inches more, it'll be in here, and I'mafraid it will rise that much before morning. At any rate we must beready for it."
"What can we do?" asked Tom in alarm. "There's no place to hide on theupper bank."
"We mustn't quit this bank, and we mustn't quit the drift-pile either,"replied Sam. "You must find a good place, high up in the drift where, bypulling out sticks, you and Joe can make a place for us to stay in."
"But, Sam, what if the water gets to us there?"
"It won't get to us there."
"How do you know?"
"Because the biggest freshets always come in the spring, and the top ofthis drift-pile was put where it is by the biggest freshets, so theriver won't go near the top in November. You see, as the drift _floated_on top of the water to its present place, the top of the pile must bethe highest point, or very nearly the highest, that the water everreaches. If you can find a good place therefore in the upper part of thedrift-pile, we shall be safe there. But you'd better see about it atonce, as the water may be in here before morning, and at any rate wemustn't allow ourselves to be taken by surprise. You'd better go to theriver and set a stake first so you can tell how fast the water rises andknow when to move into the new place."
Tom set his stake at the water's edge and then selected the mostavailable place he could find for the new abode. He and Joe wentdiligently to work, rearranging the loose sticks of drift-wood and evencarrying many of them clear out of the pile, so as to enlarge the holethey had found and make it as habitable as possible.
"The trouble is," said Tom when they had nearly completed their task,"that we can't make a smooth floor, and it's going to be ratheruncomfortable lying on loose logs and big round sticks that run everywhich way."
"That's my business," said Judie looking in at the entrance. "I'm thehousekeeper, you know, and I've thought of all that."
And sure enough the little woman had brought a great pile of small,leafy, tree branches and bush tops, with which she speedily filled upthe low places between the timbers, and covered the timbers themselvesto a depth of three or four inches, making a soft as well as a levelfloor. She had foreseen the difficulty, and borrowing Sam's knife, hadworked with all her might to provide in advance against it. But thebushes and leaves were not all that she had brought. She had collectedalso a large quantity of gray moss with which to make a carpet for thespringy floor.
"Now please don't tell brother Sam," she said when the boys praised herthoughtfulness and ingenuity. "I want to surprise him when he comes."
Tom and Joe promised, and Tom said they would have to call her their"little housekeeper" hereafter.
The river was still rising, but more slowly, it appeared, than it haddone before. By Tom's calculations it was coming up at the rate of aninch in three hours, wherefore Sam thought they might safely remainwhere they were until morning at least, while if the water should cometo a stand during the night, they would have no occasion to move at all,as a fall would rapidly follow, if the weather should remain clear.
Joe had worked faithfully at the task of preparing the new place ofrefuge, but he was not at all satisfied with the arrangement.
"I tell you, Mas' Tom," he said, "wood'll float, 'thout 'tis live oak,an' dis here drif'-pile 'll jest raise up an' float away, you'll see ifit don't."
"Why hasn't it floated away long ago, then, Joe?" asked Tom.
"May be it has. How you know dis drif' didn't all on it come here las'time de river was up?"
"Well, there's too much of it for that, and besides, Sam says this placeis safe, and you know he is always right about things when he speakspositively about them."
"Mas' Tom, don' you know Mas' Sam done been a-talkin' nonsense for twoweeks now?"
"Yes; but that's only when he's out of his head."
"How you know when he's outen his head an' when he ain't?"
"We know he's out of his head when he talks nonsense."
"Well, maybe dis here 's nonsense. I jest knows it is, and dat's how Iknow Mas' Sam was outen his head when he said it."
Tom saw that Joe was not to be convinced, and so he contented himselfwith saying,
"Well, we'll see."
"Yes, dat's jest it. We _will_ see, and feel too, when we all getsdrownded in de water."
The water came to a stand about midnight, and was falling slowly thenext morning. But when morning came it was raining hard, and the rainwas evidently not a local but a general one, wherefore, Tom feared thatthe fall would shortly be changed into a rise, and that the bank wouldsoon be covered. He watched his stake carefully, visiting it every halfhour. At nine o'clock the river had fallen three inches, and was abouteight inches below the bank. From nine to ten it fell only about half aninch. Between ten and eleven the fall was not more than a quarter of aninch. Between eleven and twelve no fall at all was perceptible. Fromtwelve to one there was a slight rise. Between one and two it rosenearly an inch. The next hour brought with it a rise of two inches. Byfive o'clock the level of the water was barely two inches below theedge of the bank, and as it was rising at the rate of two or threeinches an hour, Sam thought it time to remove from their old to theirnew quarters. The change was of advantage to the sick boy, who was nowgetting somewhat better at any rate, and when he found himself in thenew place the interest he showed in examining all the details of itsarrangements, was the best possible evidence of improvement.
"Come here, little woman," he said to Judie, "and give an account ofyourself. You borrowed my knife yesterday, and somebody has been usingit in cutting bush tops to make a smooth floor with, and the idea was avery good one. Can you tell me who it was?"
"Maybe it was Tom," she replied mischievously.
"No, it was not Tom," Sam answered. "He's too much of a great awkwardboy to think of anything so comfortable. You must guess again."
"Joe, then," she said.
"No, it wasn't Joe, either," said Sam. "Joe can sleep on the edge of afence rail as well as anywhere else, and he never would have thought ofmaking our floor soft and smooth. Guess again."
"Maybe it was brother Sam," said Judie.
"Oh, certainly. It must have been I," replied Sam. "I must have done it.I'm so strong and active now-a-days. Yes, on reflection, I presume I didit, and the man in the moon hel
ped me. Now I think it was a verythoughtful and helpful thing for anybody to do, so you ought to kiss mefor doing it, and when the weather gets clear you must throw a kiss tothe man in the moon, too, for his share." And with that he kissed thelittle housekeeper, and she felt herself abundantly repaid for her workand for the thoughtfulness she had shown. She was never so happy as whenSam praised her, "because he's such a splendid big brother," she wouldexplain.
Tom, seeing that Sam was getting better at last, began to hope for hiscomplete recovery, and the hope made him buoyant of spirit again. Judie,too, who watched and weighed every symptom in Sam's case, discovered toher delight that he was decidedly better, and the discovery made her ashappy as a healthy girl well can be. Poor Joe seemed to be the onlymiserable one in the party. He said almost nothing, answering questionswith a simple "yes" or "no," and sitting moodily in his corner, when hestayed inside the "drift cavern"--which was Sam's name for the newabode--at all. He spent most of his time, however, on top of the pile,where he watched the water and the clouds. The rain had ceased, but theriver, which was now creeping over the broad bank, continued to rise.
"What is the matter with Joe?" asked Sam after the boy had gone out forthe twentieth time.
"I think he's afraid we're all going to be drowned," said Tom.
"Drowned? How?"
"Well, he says wood will float, and so he thinks when the water comes upunder the drift-pile, it will all float away."
"What nonsense!" exclaimed Sam. "Why didn't you tell him better, Tom?"
"I did; but he sticks to it, and--"
"Well, couldn't you explain it so that he would understand it and nothave to trust to your judgment for it?"
"No, I couldn't. The fact is, I don't quite understand it myself. Thereisn't a stick in this whole pile that won't float, and I don't quiteunderstand why the pile won't. But I don't doubt you're right about it,Sam. You always are right whether I understand how things are or not."
"Let me explain it to you, then. Do you know why some things float andothers don't?"
"Yes, of course. Because the things that float are lighter than thethings that sink."
"Not exactly. That log there is too heavy for you to lift, while you cancarry a bullet between your thumb and finger. The log is many hundredtimes heavier than a bullet, but the log will float while the bulletwill sink always."
"That's so," said Tom, "and I don't know what does make some thingsfloat and other things sink."
"Did you ever set a teacup in the water and see it float?"
"Yes, many a time."
"But if you fill it with water it will sink, won't it?"
"Yes, of course."
"Well, now I can explain the thing to you, I think. If a thing isheavier,--the whole thing I mean, than the amount of water itdisplaces,--that is, if it is heavier than exactly its own bulk ofwater, it will sink; but if it is lighter than its own bulk of water itwill float."
"Oh, yes, I see."
"Now a bullet weighs a good deal more than its own bulk of water, and soit sinks. A log weighs less than its own bulk of water, and so itfloats. An empty teacup weighs less than a solid body of water equal toit in size, and it therefore floats. If you fill it with water, however,you increase its weight without adding anything to the amount of waterit displaces,--or rather, as you let water into all the hollow space,you lessen by that much the amount of water it must displace in sinkingwithout taking away anything from its weight, and so it sinks; or, ifyou break the teacup you lessen the amount of water it must displacewithout lessening its weight, and so it sinks in that case, too. Do youunderstand that?"
"Yes, I think I do," said Tom; "but I don't exactly see how it appliesto the drift-pile."
"I'll explain that presently. I want to make it plain first that theability of a thing to float depends not on its weight, but on its weightas compared with that of a like bulk of water. This comparative orrelative weight is called _specific gravity_, and in measuring thespecific gravity of substances water is taken as the standard usually,though sometimes gold is used for that purpose. Now to come to thedrift-pile. When the water rises say two or three feet, it will be abovethe level of the lower logs, and these would float away, if they werefree, because their specific gravity is less than that of water. Butthere is twenty feet of other timber on top of them, and its weight mustbe added to theirs. The water displaced is exactly equal to their bulk,while the weight is many hundred times greater than theirs. Do youunderstand?"
"Yes, I think I do. You mean that the water must come high enough topretty nearly cover the whole drift-pile before any of it can float."
"Yes. The pile must be considered as a whole, and it won't float untilthere is water enough to float the whole. The bottom logs can't floatwhile those above them are clear out of water, if their weight rests onthe bottom logs, as it does in the drift-pile. You see when you putanything into the water, it sinks until it has displaced a bulk of waterequal to its own weight, and then stops sinking. In other words, thatpart of the floating thing which goes under the water is exactly thesize of a body of water equal in weight to the whole thing. If a logfloats with just half of itself above water, you know that the logweighs exactly the same as half its own bulk of water, or, in otherwords, that its specific gravity is just half that of water. Water twoinches deep won't float a great saw-log, because a great saw-log weighsmore than the amount of water it takes to cover its lower part two orthree inches deep; and water two or three feet deep won't float adrift-pile twenty feet high, because such a drift-pile weighs a gooddeal more than a body of water two or three feet deep, of its own lengthand width. But even if the water were to rise to the top of the hammock,the pile wouldn't float away. It would float, of course, and some of thewood near its edges would be carried away, but the main pile wouldremain here, because it is all tangled together and can't go away exceptin one great mass. It is so firmly lodged against the trees as toprevent that, and as a freshet big enough to cover, or nearly cover it,would bring down a great quantity of new drift and deposit it here, thepile would grow bigger rather than smaller. But the river won't get veryhigh at this season, or at any rate it won't rise to anywhere near thetop of the hammock, as I have already explained to you, because it isevidently only the biggest freshets that ever come near the top, and thebiggest freshets never come in the fall, but always in the spring. Itisn't rising fast enough either. It isn't rising nearly so fast now asit was before it got over the bank."
"Why, how do you know that, Sam? You haven't been to look."
"No, but I know it, nevertheless, simply because I know that water, leftto itself, will find its level."
"I don't see what that's got to do with it," said Tom.
"Perhaps not, but it has something to do with it for all that," repliedSam; "and I can make you see how, too."
He paused, to think the matter over and determine how to present it toTom's comprehension.
"You see," he then resumed, "that the river inside its banks is aboutfour hundred yards wide. When it rises above the banks, however, itspreads out over the level ground, and becomes, in some places, manymiles wide, averaging a mile at least in width. Now there is only acertain amount of water coming into the river every hour. The rain hasstopped, but the soil is full of water, and so there is about as muchrunning into the river now as there was while the rain lasted. But thesurface of the stream is now many times greater than it was, and aswater finds its level, all that comes into the river spreads out overits whole surface, and of course doesn't raise its level nearly so muchas the same quantity did while the stream was still within its banks. Doyou understand now?"
"What a great big brother you are, Sam, anyhow!" was all the reply Tommade.
Big Brother: A Story of Indian War Page 15