"Humboldt, the great geologist, relates cases of tribes in South America which live for at least three months at a time on this substance, without any apparent ill effect, but from all the a.n.a.lyses made there does not seem to be anything nutritious in it. I am not surprised that Chief should have a knowledge of it."

Chief returned after an hour, apparently well satisfied with himself.

Since their return Harry and George had many times thought and talked about the cave. They debated whether or not to advise the boys of its existence, but could not satisfy themselves of the proper course to pursue. They were not selfishly considering the entire possession of the treasure. In fact they were too generous for that, but the boys would know sooner or later, and it was a question whether to disclose it now or later on. In this dilemma they called on the Professor.

"I know just how you feel about it," was the Professor's comment, "and I am not competent to advise you. It is your own property, and you may dispose of it as you wish."

"But it isn't our property. Without you it would never have been discovered, and we shall refuse to take it unless you share with us"

exclaimed George.

"No, Professor, I can never consent to that disposition of it," was Harry's determined expression, "and for my part nothing shall be done in the matter without you agree with us on the course to follow."

The Professor reflected a while, and then answered: "As for myself I have very little need for it, and there is no one near or dear to me that I would willingly leave it to." With his head bowed, he became silent, and then continued, in a most eager manner: "I had entirely forgotten. I have some who are near and dear to me; I ought to remember them, after all, and as you insist on it, you will pardon me, I know, if I consent to take a portion of it, at least."

"It must be divided into thirds. I am sure there is enough there to make a great many people happy."

"Weren't you boys happy before you acquired this treasure?"

"Yes; as happy as we could be in our condition."

"Do you think the treasure in the cave would make you any happier than you have been?"

"Well, if we ever get out of here we can use it to good advantage."

"That is the whole secret of happiness with wealth--the knowledge of how to use it."

When they left the Professor the boys wondered why at first he declared that he had no one that he cared to leave the money to, and then suddenly remembered that he did have some whom he cared for. The Professor was as much a mystery to them as many of the things which had come to them during their sojourn on the island. This was, in fact, the only information that they had ever gleaned from him concerning his home, his family, or his friends, and that was very meager at the most.

The boys were anxious to revisit the cave, and the Professor was pleased at their determination, but advised them to make the visit themselves, and to endeavor to find out the full extent of the subterranean windings, and also suggested that they should try to make a working chart of it for their own information.

It was a little difficult now, since the close a.s.sociation had grown up between Harry and Tom, on the one hand, and George and Ralph on the other, to find a suitable excuse for the absence of Harry and George, but the Professor arranged this without creating suspicion on their part.

"I think Ralph is a mighty fine fellow, and we get along splendidly, and I don't think I ever met a pair of more unselfish boys," said George, as they walked up the hill.

"That is my opinion, too. Tom is a most wholesouled fellow, and we find so much that is likeable in each other, that I tell you I do not feel like being so n.i.g.g.ardly as to keep the knowledge of the cave and the treasure away from them; and I feel the more about it that way when I think of the terrible suffering they have gone through."

"Just my idea, exactly. How much do you really think there is in the cave? I mean, what do you think it is worth in money?"

"I am sure the Professor knows. It would be awfully interesting to know.

Isn't it funny the Professor never said anything about the worth of it?"

"Yes, he did. Don't you remember, just before we left on the big trip he wanted to know whether we cared to take the risks among the savages, when we had so much treasure in sight?"

"Yes, but that didn't indicate whether there was a thousand or a million there."

When they reached the entrance to the cave, they sat down and talked over the matter again. The lamps were left unlighted, and they made no effort to enter it.

"I have half a notion to go back and talk to the Professor, and bring the boys over." George looked at Harry inquiringly.

"Do you really mean it?" asked Harry.

"I do."

"Look over there; see who is coming," said George, with a laugh.

Red Angel was on the way with his gun. "You little rascal! How did you find out we were over here?" He didn't answer, but he went up to George and looked up into his face, as though he didn't quite understand that kind of a greeting.

The boys picked up the lamps and went back to the house, and the Professor was surprised at the early return, but he did not make any mention of it to either of the boys, and nothing more was said about it during that day or evening.

CHAPTER XIII

THE ACCIDENT TO JOHN AND THE RESTORATION OF MEMORY

The island yielded an abundance of nuts of various descriptions, the most prolific being the Brazil nut, which grows in the form of a large sphere, from three to four inches in diameter, the sh.e.l.l being very hard, like the cocoanut, and when broken open is found to be filled with the segmentally formed nuts which we all know.

This was gathered in large quant.i.ties, and was the princ.i.p.al source of oil which was used for the lamps, as they had no other means of illumination. To people in the habit of using the lighter mineral oils, and electricity, this was certainly primitive enough. The difficulty, however, with the gathering of the nuts was this: Unless gathered at a certain time it is almost impossible to express the oil, and if kept for any length of time, particularly in an unripe state, they would become very rancid.

George pondered over this for some time, and asked the Professor the cause of it. In response, he said: "Nature has a very peculiar way of protecting her products. It is the same with nuts, as it is with potatoes and fruit. Have you ever noticed how unripe fruit withers, when taken from the tree, and that potatoes shrivel up when they are dug up before fully matured?"

"That is the trouble with the whole batch of potatoes we now have."

"Unripe fruit and vegetables have an exterior coating which is porous and pervious to water when it is unripe. But when it fully ripens this coating is chemically changed into a thin, impervious coating of a cork-like structure, through which water cannot pa.s.s, and as a result potatoes, and fruit, will keep through an entire winter and become mellower and better as time goes on."

The colony was dependent for its supply of eggs on the numerous flocks of prairie chickens which were found in the abounding fields of grain, particularly barley. It was no trick to bag a half dozen of these birds at a shot, on account of their numbers, and, as before related, while Angel never ate any of them, he was the most persistent gatherer because the beautiful oval eggs attracted him, and George's cakes always appealed to his fancy.

The difficulty with Angel was he did not discriminate between the good and the bad eggs, and George was desirous of knowing how to distinguish between the fresh and spoilt ones.

As usual, the Professor was appealed to and he gave a standard rule for determining this: "As Angel brings in the eggs put them in a pail of water, and select only those which fall to the bottom and rest on the side. An egg several weeks old will remain at the bottom, but the large end will be much higher than the small end. If it is several months old the large end will be uppermost, with the small end pointing down; and if it is thoroughly rotten it will float at the top of the water, with the pointed side down."

"That is a very curious way of finding it out. I would like to know why the egg acts in that manner?"

"After an egg is laid, a chemical change begins to take place, and more or less gas is formed. This gas finds its way to the large end, and as the decomposition increases the egg becomes lighter at the heavy end, and finally enough gas is evolved to bring it to the surface."

[Ill.u.s.tration: _Fig. 15._ TESTING EGGS]

The most important work on hand was the construction of the addition to their home. After considering the matter in all its details, it was concluded to put up a building entirely separate from the other structures, to contain four rooms, one of them to be large and utilized as a common living room, and the others as sleeping apartments.

The material had been taken out for the building, and the Professor, John, George and Ralph were engaged at this work, while Harry and Tom were engaged in the machine shop and were busy in turning out the barrels for new guns, as well as preparing the ammunition.

The tools in the machine shop were not numerous enough to advantageously utilize more of them there, and the building was now very important to them, as the four boys were compelled to sleep in the shop, for want of room in the house.

The joist had all been laid for the lower floor and the studding now being put up and the upper joist laid on preparatory to erecting the rafters. John was an expert in building, and was really the directing hand at the various steps in the operation. While engaged in the drawing up of the rafters, one of the floor pieces gave way, and John was precipitated to the floor below, striking as he fell one of the lower joist, which cut a terrible gash in his head and rendered him unconscious.

The Professor rushed over to the fallen man, and the boys were on the spot to render a.s.sistance. Chief, who was also an interested worker, was the first to grasp him with his powerful arms, and disdaining the a.s.sistance of the others, carried him to the house and gently laid him down, as the Professor directed.