AT Slipper Point, they established Genevieve, as usual, on the old chair in the cave, to examine by candle-light the new picture-book that Doris had brought for her. This was calculated to keep her quiet for a long while, as she was inordinately fond of “picters,” as she called them.

“Now,” cried Sally, “what about that paper?”

“Oh, I don’t know that it amounts to very much,” explained Doris. “It just occurred to me, in looking it over, that possibly the fact of its being square and the little cave also being square might have something to do with things. Suppose the floor of the cave were divided into squares just as this paper is. Now do you notice one thing? Read the letters in their order up from the extreme left hand corner diagonally. It reads r-i-g-h-t-s and the last square is blank. Now why couldn’t that mean ‘right’ and the ‘s’ stand for square,—the ‘right square’ being that blank one in the extreme corner?”

“Goody!” cried Sally. “That’s awfully clever of you. I never thought of such a thing as reading it that way, in all the time I had it. And do you think that perhaps the treasure is buried under there?”

“Well, of course, that’s all we can think it means. It might be well to investigate in that corner.”

But another thought had occurred to Sally. “If that’s so,” she inquired dubiously, “what’s the use of all the rest of those letters and numbers. They must be there for something.”

“They may be just a ‘blind,’ and mean nothing at all,” answered Doris. “You see they’d have to fill up the spaces somehow, or else, if I’m right, they’d have more than one vacant square. And one was all they wanted. So they filled up the rest with a lot of letters and figures just to puzzle any one that got hold of it. But there’s something else I’ve thought of about it. You notice that the two outside lines of squares that lead up to the empty squares are just numbers,—not letters at all. Now I’ve added each line together and find that the sum of each side is exactly twenty-one. Why wouldn’t it be possible that it means the sides of this empty square are twenty-one—something—in length. It can’t possibly mean twenty-one feet because the whole cave is only about nine feet square. It must mean twenty-one inches.”

Sally was quite overcome with amazement at this elaborate system of reasoning it out. “You certainly are a wonder!” she exclaimed. “I never would have thought of it in the world.”

“Why, it was simple,” declared Doris, “for just as soon as I’d hit upon that first idea, the rest all followed like clockwork. But now, if all this is right, and the treasure lies somewhere under the vacant square, our business is to find it.”

Suddenly an awful thought occurred to Sally. “But how are you going to know which corner that square is in? It might be any of the four, mightn’t it?”

For a moment Doris was stumped. How, indeed, were they going to tell? Then one solution dawned on her. “Wouldn’t they have been most likely to consider the square of the floor as it faces you, coming in at the door, to be the way that corresponds to the plan on the paper? In that case, the extreme right-hand corner from the door, for the space of twenty-one inches, is the spot.”

It certainly seemed the most logical conclusion. They rushed over to the spot and examined it, robbing Genevieve of her candle in order to have the most light on the dark corner. It exhibited, however, no signs of anything the least unusual about it. The rough planks of the flooring joined quite closely to those of the wall, and there was no evidence of its having ever been used as a place of concealment. At this discouraging revelation, their faces fell.

“Let’s examine the other corners,” suggested Doris. “Perhaps we’re not right about this being the one.”

The others, however, revealed no difference in their appearance, and the girls restored her candle to Genevieve at the table, and stood gazing at each other in disconcerted silence.

“But, after all,” suggested Doris shortly, “would you expect to see any real sign of the boards being movable or having been moved at some time? That would only give their secret away, when you come to think of it. No, if there is some way of opening one of those corners, it’s pretty carefully concealed, and I don’t see anything for it but for us to bring some tools up here,—a hammer and saw and chisel, perhaps,—and go to work prying those boards up.” The plan appealed to Sally.

“I’ll get some of Dad’s,” she declared. “He’s got a lot of tools in the boathouse, and he’d never miss a few of the older ones. We’ll bring them up tomorrow and begin. And I think your first idea about the corner was the best. We’ll start over there.”

“I’s cold,” Genevieve began to whimper, at this point. “I don’t like it in here. I want to go out.”

The two girls laughed. “She isn’t much of a treasure-hunter, is she!” said Doris. “Bless her heart. We’ll go out right away and sit down under the pine trees.”

They emerged into the sunlight, and Sally carefully closed and concealed the entrance to their secret lair. After the chill of the underground, the warm sunlight was very welcome and they lay lazily basking in its heat and inhaling the odor of the pine-needles. Far above their heads the fish-hawks swooped with their high-pitched piping cry, and two wrens scolded each other in the branches above their heads. Sally sat tailor-fashion, her chin cupped in her two hands, thinking in silence, while Doris, propped against a tree, was explaining the pictures in her new book to Genevieve. In the intervals, while Genevieve stared absorbedly at one of them, Doris would look about her curiously and speculatively. Suddenly she thrust the book aside and sprang to her feet.

“Do you realize, Sally,” she exclaimed, “that I’ve never yet explored a bit of this region above ground with you? I’ve never seen a thing except this bit right about the cave. Why not take me all round here for a way. It might be quite interesting.”

Sally looked both surprised and scornful. “There’s nothing at all to see around here that’s a bit interesting,” she declared. “There’s just this pine grove and the underbrush, and back there,—quite a way back, is an old country road. It isn’t even worth getting all hot and tired going to see.”

“Well, I don’t care, I want to see it!” insisted Doris. “I somehow have a feeling that it would be worth while. And if you are too tired to come with me, I’ll go by myself. You and Genevieve can rest here.”

“No, I want to go wis Dowis!” declared Genevieve, scrambling to her feet as she scented a new diversion.

“Well, I’ll go too,” laughed Sally. “I’m not as lazy as all that, but I warn you, you won’t find anything worth the trouble.”

They set off together, scrambling through the scrub-oak and bay-bushes, stopping now and then to pick and devour wild strawberries, or gather a great handful of sassafras to chew. All the while Doris gazed about her curiously, asking every now and then a seemingly irrelevant question of Sally.

Presently they emerged from the pine woods and crossed a field covered only with wild blackberry vines still bearing their white blossoms. At the farther edge of this field they came upon a sandy road. It wound away in a hot ribbon till a turn hid it from sight, and the heat of the morning tempted them no further to explore it.

“This is the road I told you of,” explained Sally with an “I-told-you-so” expression. “You see it isn’t anything at all, only an old back road leading to Manituck. Nobody much comes this way if they can help it,—it’s so sandy.”

“But what’s that old house there?” demanded Doris, pointing to an ancient, tumbledown structure not far away. “And isn’t it the queerest-looking place, one part so gone to pieces and unkempt, and that other little wing all nicely fixed up and neat and comfortable!”

It was indeed an odd combination. The structure was a large old-fashioned farmhouse, evidently of a period dating well back in the nineteenth century. The main part had fallen into disuse, as was quite evident from the closed and shuttered windows, the peeling, blistered paint, the unkempt air of being not inhabited. But a tiny “L” at one side bore an aspect as different from the main building as could well be imagined. It had lately received a coat of fresh white paint. Its windows were wide open and daintily curtained with some pretty but inexpensive material. The little patch of flower-garden in front was as trim and orderly.

“I don’t understand it,” went on Doris. “What place is it?”

“Oh, that’s only Roundtree’s,” answered Sally indifferently. “That’s old Miss Roundtree now, coming from the back. She lives there all alone.”

As she was speaking, the person in question came into view from around the back of the house, a basket of vegetables in her hand. Plainly she had just been picking them in the vegetable-garden, a portion of which was visible at the side of the house. She sat down presently on her tiny front porch, removed her large sun-bonnet and began to sort them over. From their vantage-point behind some tall bushes at the roadside, the girls could watch her unobserved.

“I like her looks,” whispered Doris after a moment. “Who is she and why does she live in this queer little place?”

“I told you her name was Roundtree,—Miss Camilla Roundtree,” replied Sally. “Most folks call her ‘old Miss Camilla’ around here. She’s awfully poor, though they say her folks were quite rich at one time, and she’s quite deaf too. That big old place was her father’s, and I s’pose is hers now, but she can’t afford to keep it up, she has so little money. So she just lives in that small part, and she knits for a living,—caps and sweaters and things like that. She does knit beautifully and gets quite a good many orders, especially in summer, but even so it hardly brings her in enough to live on. She’s kind of queer too, folks think. But I don’t see why you’re so interested in her.”

“I like her looks,” answered Doris. “She has a fine face. Somehow she seems to me like a lady,—a real lady!”

“Well, she sort of puts on airs, folks think, and she doesn’t care to associate with everybody,” admitted Sally. “But she’s awfully good and kind, too. Goes and nurses people when they’re sick or have any trouble, and never charges for it, and all that sort of thing. But, same time, she always seems to want to be by herself. She reads lots, too, and has no end of old books. They say they were her father’s. Once she lent me one or two when I went to get her to make a sweater for Genevieve.”

“Oh, do you know her?” cried Doris. “How interesting!”

“Why, yes, of course I know her. Everyone does around here. But I don’t see anything very interesting about it.” To tell the truth, Sally was quite puzzled by Doris’s absorption in the subject. It was Genevieve who broke the spell.

“I’s sirsty!” she moaned. “I want a djink. I want Mis Camilla to gi’ me a djink!”

“Come on!” cried Doris to Sally. “If you know her, we can easily go over and ask her for a drink. I’m crazy to meet her.”

Still wondering, Sally led the way over to the tiny garden and the three proceeded up the path toward Miss Roundtree.

“Why, good morning!” exclaimed that lady, looking up. Her voice was very soft, and a little toneless, as is often the case with the deaf.

“Good morning!” answered Sally in a rather loud tone, and a trifle awkwardly presented Doris. But there was no awkwardness in the manner with which Miss Camilla acknowledged the new acquaintance. Indeed it was suggestive of an old-time courtesy, now growing somewhat obsolete. And Doris had a chance to gaze, at closer range, on the fine, high-bred face framed in its neatly parted gray hair.

“Might Genevieve have a drink?” asked Doris at length. “She seems to be very thirsty.”

“Why, assuredly!” exclaimed Miss Camilla. “Come inside, all of you, and rest in the shade.” So they trooped indoors, into Miss Camilla’s tiny sitting-room, while she herself disappeared into the still tinier kitchen at the back. While she was gone, Doris gazed about with a new wonder and admiration in her eyes.

The room was speckless in its cleanliness, and full of many obviously home-made contrivances and makeshifts. Yet there were two or three beautiful pieces of old mahogany furniture, of a satiny finish and ancient date. And on the mantel stood one marvelous little piece of pottery that, even to Doris’s untrained eye, gave evidence of being a rare and costly bit. But Miss Camilla was now coming back, bearing a tray on which stood three glasses of water and a plate of cookies and three little dishes of delicious strawberries.

“You children must be hungry after your long morning’s excursion,” she said. “Try these strawberries of mine. They have just come from the garden.”

Doris thought she had never tasted anything more delightful than that impromptu little repast. And when it was over, she asked Miss Camilla a question, for she had been chatting with her all along, in decided contrast to the rather embarrassed silence of Sally.

“What is that beautiful little vase you have there, Miss Roundtree, may I ask? I’ve been admiring it a lot.” A wonderful light shone suddenly in Miss Camilla’s eyes. Here, it was plain, was her hobby.

“That’s a Louis XV SÈvres,” she explained, patting it lovingly. “It is marvelous, isn’t it, and all I have left of a very pretty collection. It was my passion once, this pottery, and I had the means to indulge it. But they are all gone now, all but this one. I shall never part with this.” The light died out of her eyes as she placed the precious piece back on the mantel.

“Good-bye. Come again!” she called after them, as they took their departure. “I always enjoy talking to you children.”

When they had retraced their way to the boat and pushed off and were making all speed for the hotel, Sally suddenly turned to Doris and demanded:

“Why in the world are you so interested in Miss Camilla? I’ve known her all my life, and I never talked so much to her in all that time as you did this morning.”

“Well, to begin with,” replied Doris, shipping her oars and facing her friend for a moment, “I think she’s a lovely and interesting person. But there’s something else besides.” She stopped abruptly, and Sally, filled with curiosity, demanded impatiently,

“Well?”

Doris’s reply almost caused her to lose her oars in her astonishment.

“I think she knows all about that cave!”