You must dig a sort of fireplace in the sand bank and build your fire in there. When it burns away until you have a good bank of coals, you must put down on them a layer of the corn, in the shuck, then a layer of mussels, then a layer of corn, and finally cover them all up with coals and hot ashes, and leave them there for an hour or two, when they will be cooked beautifully."

"But Mas' Sam," said Joe.

"Well, what is it, Joe?"

"How's we gwine to git de fire?"

"Well, how do you think, Joe?"

"I 'clare I dunno, Mas' Sam, 'thout you got some flints an' punk in your pockets."

"No, I have no flints and no punk, Joe, but I'm going to get you some fire when the sun gets straight overhead."

"Is you gwine to git it from de sun, Mas' Sam?"

"Yes."

"What wid, Mas' Sam?"

"With water, Joe."

"Wid water, Mas' Sam! You'se foolin'. How you gwine to git fire wid water, _I'd_ like to know."

"Well, wait and see. I'm not fooling."

To tell the truth, Tom was quite as much at a loss as Joe was, to know how Sam could get fire with water; but his confidence in his "big brother," as he called Sam, was too perfect to admit of a doubt or a question. As for Judie, she would hardly have raised her eyebrows if Sam had burned water, or whittled it into dolls' heads before her eyes. She believed in Sam absolutely, and supposed, as a matter of course, that he knew everything and could do anything he liked. But Joe was not yet satisfied that water could be made to a.s.sist in the kindling of a fire.

He said nothing more, however, but carefully watched all of Sam's preparations.

That young gentleman began by tearing a strip of cotton cloth from his shirt, and picking it to pieces. He then gathered from the drift-wood a number of dry sticks, and broke and split them up very fine.

"We must have a few splinters of light-wood," he said; "but after the fire is once started, we mustn't put any more pine on."

So saying, he split off a few splinters from a piece of rich heart-pine, which Southern people call "light-wood," because the negroes use it instead of lamps or candles.

"Come now," said Sam, "its nearly noon, and I think I can get fire for you. Go up on top of the drift-pile, Tom, and look out for Indians. If you don't see any we can all go down to the spring together long enough to start a fire. Then I must come back to Judie, and I'll keep a look-out for Indians while you and Joe get the corn on. When you get it on, come back here and wait until it has time to cook. Stop a minute, Tom. Let's understand each other. If the one on the look-out sees Indians, he must let the others know; but it won't do to holler. Let me see. Can you whistle like a kildee, Tom?"

"Yes, or like any other bird."

"Can you, Joe?"

"I reckon I _kin_, Mas' Sam," said Joe, who, to prove his powers straightway gave a shrill kildee whistle, which nearly deafened them all.

"There, that'll do, Joe. Well, let's understand then, that if anyone of us sees Indians, he must whistle like a kildee. If the Indians hear it they'll think nothing of it."

Tom went to the look-out, and seeing no savages anywhere, returned, and the whole party, little Judie excepted, proceeded to the spring. Sam then laid his sticks down in a pile, and taking out his watch removed the crystal. This he filled with clear water from the spring, and holding it over the cotton ravellings, moved it up and down until the sunlight, pa.s.sing through it, gathered itself into a small bright spot on the cotton. Joe, eager to see, thrust his head over Sam's shoulder, and directly between the gla.s.s and the sun.

"Take your head away, Joe, or I'll have to draw the fire right through it," said Sam, laughing.

"Mercy, Mas' Sam, don't do dat. I'se 'feard o' your witches' ways, anyhow," said Joe, drawing back. The gla.s.s was again put in position and the spot of bright sunlight reappeared. Presently a little cloud of smoke rose, and a moment afterwards, the cotton was fairly afire. It was not difficult now to get the light-wood and dry sticks to blazing, and a good fire was soon secured.

"Now boys," said Sam, "I'll go back to the drift-pile and keep a look-out. If you hear the kildee call, run in as quickly as you can.

When you get the corn and mussels on, and covered up, come back at once."

No Indians showing themselves anywhere in the neighborhood, the boys got their dinner on or rather _in_ the fire, and then returned to the root cavern to await the completion of the cooking process. When they were all safely stowed away in their places, Tom gave voice to the curiosity with which he was almost bursting.

"Sam," he said, "how did you do that?"

"How did I do what, Tom?"

"How did you make the sun set the cotton on fire?"

"I don't know whether I can make you understand it or not," said Sam, "but I'll try. You know light always goes in straight lines, if left to itself, don't you?"

"No, I didn't know that!

"Yes you did, only you never thought of it. If you want to keep light out of your eyes, you always put your hand between them and the light, because you know the light goes straight and so will not go around your hand."

"Yes, that's true, and when I want to make a shadow anywhere, I put something right before the light."

"Certainly. Well, the rays of the sun all come to us straight, and side by side. They are pretty hot, but not hot enough to set fire to anything that way. But if you can gather a good many of these rays together and make them all shine on one little spot, they will set fire to whatever they fall on. Now a piece of gla.s.s or any other thing that you can see through easily,--that is, any _transparent_ thing, lets the sunlight through it, and if it is flat on both sides, it doesn't change the directions of the rays. But if both sides are rounded out, or if one side is rounded out and the other side is flat, it turns all the rays a little, and brings them right together in a point not far from the gla.s.s. If the sides are hollowed _in_ instead of bulging out, the rays scatter, and if one side bulges out and the other bulges in, as they do in a watch crystal, one side scatters and the other side collects the rays, and so it is the same as if the gla.s.s had been perfectly flat, one side undoes the other's work. Now I have no gla.s.s which bulges out on both sides, and none that bulges out on one side and is flat on the other, but my watch crystal bulges out on one side and in on the other.

But when I filled it with water, the water being as clear as the gla.s.s, it made it flat on top and bulging underneath, and so it gathered the sun's rays together in the light spot you saw, and set fire to the cotton."

"Yes, but why did you have to wait till noon?" asked Tom.

"Because the gla.s.s must be held right across the rays of light, and as I couldn't turn the crystal to either side without spilling the water, I had to use it at noon, when the sun was almost exactly overhead, and its rays came nearly straight down. If I had had a gla.s.s rounded out on both sides I could have got fire any time after the sun was well up in the sky. Now let me tell you what they call all these different kinds of gla.s.ses. One that is flat on one side and bulges out on the other is called a _convex lens_; if it bulges out on both sides it is a _double convex lens_; if it is hollowed in on one side and flat on the other it is a _concave lens_; if hollowed in on both sides we call it a _double concave lens_; and when it is hollowed in on one side and bulged out on the other, as any watch crystal does, it is a _concave convex lens_."

"Where did you learn all that, Sam?" asked Tom.

"I learned part of it with father's spectacles, and part out of a book father lent me when I asked him why I couldn't make the bright, hot spot with a pair of near-sighted gla.s.ses that I found in one of mother's old work boxes. You see, when people begin to get old, their eyes flatten a little, and so everything they look at seems to be shaved off. They see well enough at a distance, but can't see small things close to them."

"Is that the reason pa always looks over his spectacles when he looks at me?" asked Judie.

"Yes, little woman. He can't see to read without his gla.s.ses, but he can see you across the room without them, well enough. Well, to remedy this defect, old people wear spectacles with double convex lenses in them. But near-sighted people have exactly the opposite trouble. They can't see things except by bringing them near their eyes, because their eyes are not flat enough, and so their spectacles are made with double concave lenses. When I asked father about it, he gave me a book that explained it all, and that is where I learned the little I know about it."

"The _little_! I'd like to know what you call a good deal," said Tom. "I never saw anybody that knew half as much as you do."

"That is only because we live in a new country, Tom, where there are no very well educated people, and because you don't know how much there is to learn in the world. If these Indians ever get quiet, I hope to learn a good deal more every year than I know now. But it's time to see about our mussel bake. Run to the look-out, Tom, and then we can all go down and bring up the dinner."

CHAPTER VI.

SURPRISED.

The baked corn and mussels made a savory dish, or one which would have been savory enough but for the absence of salt. The boys knew well enough that salt was not to be had, however, and so they made a joke of its absence, and even pretended that they did not like their food salted at any time. Little Judie was so hungry that she cared very little whether food tasted well or not, provided it satisfied her appet.i.te.

The rest and the more wholesome food seemed to restore Sam to something like his customary strength during the first ten days of his stay in the "root fortress," as he had named their singular dwelling. His wounded foot got better, though it was still far from well, and, better than all, his fever left him. As he regained strength he began to lay plans again. To stay where they were was well enough as a temporary device for escaping the savages, but Sam's main purpose now was to get the little people under his charge back to civilization somewhere, and then to do his part in the war between the Indians and whites. He must first find a way to get Tom and Judie and Joe into one of the forts or into some safe town, and how to do this was the problem. He was unwilling to take them away from their present pretty secure hiding-place until he could decide upon some definite plan offering a reasonable prospect of escape. If he could have known as much as we now know of the movements of the savages, he would have had little difficulty. The larger part of the Indians had left the peninsula now forming Clarke County, and crossed to the south-eastern sh.o.r.e of the Alabama river,--the side on which Sam's root fortress stood, and if he could have known this, he would have made an effort to cross the river again and reach Fort Gla.s.s. The chief difficulty in the way of this undertaking would have been that of crossing the river, which was now swollen by recent rains. He knew nothing about the matter, however, and as Fort Mims, the first point attacked by the savages, was on the south-east side of the river, he reasoned that having afterwards crossed to Clarke County the Indians would not again cross to the south-east side in any considerable force.