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The Wonder Island Boys: Exploring the Island By Roger Thompson Finlay Characters: 19518

Updated: 2017-12-06 00:03

"What is that weed you have, Professor? The root looks like a parsnip."

"It may be something we can drink."

"It looks just like a weed that grows all over our farm at home."

"I have no doubt of it. This is the endive, as it is known in the States, but it is really chicory."

"I have heard of chicory; isn't it used as a substitute for coffee?"

"Principally on account of the bitterness in it. The French make the greatest use of it, because they claim it gives strength to coffee."

"What part of it is used?"

"The root; the bulb you see here, and they have a curious way of preparing it. The root is dug up before the plant shoots into flower, and is washed, sliced and dried! it is then roasted until it is of a chocolate color. Two pounds of lard are roasted with each hundredweight; and afterwards, when ground and exposed to the air, it becomes moist and clammy, increases in weight, and smells like licorice. When put into cold water it gives a sweetish bitter taste, not unlike coffee."

"Let me try some of it, and don't say anything about it to Harry. And now, while I think about it, why couldn't we make some crocks out of our clay, so we can use them for our milk. We can't put them in the copper vessels and the iron is just as bad."

"That is a splendid idea; and you might as well vitrify them."

"What do you mean by vitrifying them?"

"Putting the glaze on them, just like the common crocks have."

"That would be simply fine."

The Professor explained the process, which consisted in making the crocks out of the best clay available, and then burning them. Afterwards an intense heat must be made in the furnace, and after soaking the crocks in a strong solution of salt brine, they must be put in and burned again; the greater the heat, the better.

The boys started at this with a will, and when they had arranged to make the crocks they found it most difficult to put them into a round and uniform shape.

"I would suggest that you make a potter's wheel for that purpose."

"A potter's wheel? What is it like?"

"It is the simplest thing imaginable. Do you think, Harry, you could turn out a wooden vessel just the size of the outside of an ordinary milk crock, and turn it with a central stem below, and also have a little pulley on that stem?"

The Professor made a drawing (Fig. 29), which shows just how he wanted it made. In the drawing, A is the cup-shape, which is the size and shape of outside the crock; B is the central stem; and D is the small pulley on the stem. This was mounted in a pair of arms like CC, and a belt was attached to the pulley.

"You have made a very creditable article. Now you may make a flat paddle, and shape one end so that it will be just like the inside of the crock."

* * *

Fig. 29. Potters Wheel.

* * *

The drawing (Fig. 30) shows how it was made, with a cross handle at the upper end.

That day the crocks were turned out in the following manner: The potter's wheel was rotated about sixty turns a minute, and the clay, in a plastic state, was put in the cup-shaped top, and the hands used to force the clay up the side wall. When the crock was formed in as even a manner as it could be by hand, the blade described was used to make the interior uniform.

The potter's wheel is one of the oldest tools known. Its use can be traced back for more than four thousand years, when it was well known by the Egyptians.

* * *

Fig. 30. Forming blade for inside of Crock.

* * *

Since the day that the boys visited Observation Hill, at the time they discovered the skeleton and fragments of the boat, no attempt had been made to visit the cave. That was the mission when they accidentally made their surprising discovery.

George did not, however, feel that they should again make the attempt until they had a better lighting means than the unsatisfactory candles, and when the supposed petroleum vein dashed all hopes of lighting material from that quarter, the only remedy seemed to be by way of improving their candle-light.

Harry had progressed well in the making of the battery. It was now in a completed state, and he announced that the first tests would be made the next day. In the morning all assembled in the factory, and the sulphuric acid solution was made up.

The Professor inspected the batteries. Ten cells had been prepared, so that they could have, at least, fifteen volts. When all the cells had been connected together-that is, the positive pole of one cell with the negative pole of the other-a wire was attached at each end of the row of cells, at the last electrodes, so as to form the outside connections.

When the two outside wires were brought together and their contact broken a spark was plainly shown, which was an indication that the battery was generating electricity. The boys danced about with joy at this exhibition. From that time forward the battery was one of the most interesting things in the laboratory, and what they finally accomplished with it will be fully detailed as we go along in their history.

George thought he saw a way to make the light necessary for the cave. "Why can't we rig up an electric light now and explore the cave?"

"We might do that, but we have several things to do before we can have light from that source."

"Haven't we the electricity for it?"

"Do you know how many years electricity was known before electric light was discovered? Before we can utilize this agency for lighting purposes, we must make a machine which will produce a vacuum; we must make glass; we must learn to carbonize threads; and the art of blowing glass would be a necessary accomplishment."

"As usual," said Harry, "something must be made to make something that makes something else."

"But can we make electric light without putting it in a glass bulb?"

"Yes; we can make what is called the arc light; instead of the incandescent."

"What is the difference between the two?"

"In the incandescent, such as we talked about making, a thin carbon filament is enclosed in a glass bulb, from which as much air as possible has been exhausted, and when a current of electricity passes through this filament, it is heated up to a white heat."

* * *

Fig. 31. The Electric Arc.

* * *

"Why doesn't it burn out?"

"It does burn out in time. What preserves it, however, for a long time, is that most of the oxygen has been exhausted from the bulb--"

"Oh, yes; I know, there must be oxygen to support combustion, so that the carbon is merely heated up?"

"I am glad you remembered that. The arc light, on the other hand, depends on an entirely different thing. You have seen, no doubt, the long black pencils used in the large lamps. That is carbon also, made out of ground coke, molded and compressed into shape."

"What does arc mean!"

"Did you notice that when we put together the two circuiting ends of the wires in our battery this morning, we could not notice the existence of a current, but whenever we pulled them apart we had a spark?

"Let us now make a little experiment which will show you the arc. You see, I am making a sharp point at the end of each wire, and I will fasten one of the wires so it cannot be moved. Now the other wire will be placed with its point as close to the other points as possible, and so fixed to the support that we can adjust it still closer and hold it. See, the points now touch each other. I will move one of the wires the slightest distance away from the other. There! see the light?"

"But it goes out in a little while; what is the cause of that?"

"The electricity has been burned off the end of the wire, and the distance is now too great for the electricity to jump from one to the other, so they must be moved closer together. That space between the ends of the two wires is the electric arc. Instead of the two wires the carbon pencils are used."

"But how are the two carbon pencils kept apart at the right distance at all times?"

"That is what the invention of the arc light consisted in; to find a means whereby the current itself makes the adjustment necessary to furnish a steady, constant light. When we start to make the arc light the mechanism can be explained."

George's scheme of the electric lamp for the cave had vanished. But the cave must be explored. He was determined on that point.

The yaks were brought out and a start made for the cliffs. After unhitching them from the wagon and unyoking the animals, so they could feed in the meantime, the oil lamps were taken out and carefully examined. The Professor had suggested the advisability of carrying with them two of the spears, which, it will be remembered, formed part of the weapon equipment of their last voyage, and those, with the guns, were considered sufficient for any foe likely to be in the cave.

Harry, on this occasion, volunteered to mount Observation Hill for their daily trip of observation. He returned by the time the yaks were disposed of and the implements prepared, as stated.

"I suggest," said the Professor, "that we keep constantly on the alert now for any vestiges of driftwood, or other objects which we are likely to find along the shore."

As a result the progress was slow, and the scrutiny keen on the part of all. As they rounded the last large projecting rock, just before entering the gorge which led to the cave, Harry jumped on a rock, waving his hand, and crying, as he pointed seaward: "A sail! A ship! See it?"

The agitation of George was beyond all description. Harry kept repeating the words. He was entirely beyond control.

"Be calm; do not become excited. Harry, you are the most nimble; run to Observation Hill: here take the large sheet in the wagon; wave i

t there, and keep up the signaling; they may see you."

The ship, although far away, was plainly made out, but its character could not be determined. It was evidently a large sailing vessel. Just imagine what must have been the feelings of the party at the sight of the ship, although so far away. Would they see the signal?

In the commotion that followed, what was the Professor doing? He quickly placed two stakes in line with the ship, and watched it patiently. "It is moving to the west."

George's curiosity induced him to look over the Professor's shoulder, and thus enable him to follow the movement of the boat, and by means of which he could see the sails slowly move past the distant stake.

The Professor scarcely moved. "What is Harry doing? Is he still signaling?"

"Yes; he hasn't stopped since he reached the hill."

The stake nearest the Professor was again moved over a trifle as the ship moved on, and they watched and waited.

"Why, the ship hasn't moved for the last ten minutes."

"It seems not," was the Professor's response. Again they waited. George walked to the stakes and back again. He stepped aside to look at Harry on the hill, and again returned to the observation stakes.

"Singular that the ship hasn't moved in twenty minutes or more."

Then, enthusiastic at the mere thought, he cried out, as he ran toward the Professor: "Do you think they have seen our signal? Have they stopped; and are they returning?"

"Either that or they have changed their course, and are now leaving us dead ahead."

This was a blow to the poor boy, whose hopes, brought about by the apparently checked motion of the ship, were now dashed to the ground, when the Professor continued: "They are sailing away, I am sorry to say."

He left the observation stakes. Poor Harry was still signaling frantically. The Professor told Harry that further effort in that direction would be useless, and he slowly and sadly came down the hill.

They looked at each other most sorrowfully, and the boys could scarcely restrain their tears, while the Professor carefully avoided their gaze, or seemed not to notice their grief.

"It is one satisfaction to know," said Harry, as he dolefully looked across the broad sea, "that vessels do come this way, and that it is not out of the world entirely."

George quickly recovered. "Why not make a big signal flag for Observation Hill?" This was seconded by the Professor.

"And while we are about it why not make a good old American flag?" was Harry's comment.

The cave had been forgotten in this incident. When their wondering and questionings had ceased, the descent was made around the point, and the entrance soon reached.

The two lamps were now lighted, and the explorations began.

"I think it is advisable," was the Professor's first observation, "that we go in a hundred feet or so, and then mount one of our lamps in a conspicuous place. We can then proceed with the other as far as the water, and if any accident happens it will not cause trouble to both of the lights. We can always have one of them to fall back on."

When they had gone the distance determined on, a secure ledge was selected, and Harry placed the light so it would cast its beams along the cave.

"Be careful now, we are near the water."

The Professor had now the other light, and the boys led the way, so the beams from the light shone past ahead of them. They went beyond the point where the water had been found previously, but there was no sign of it. The course of the cave now changed to the right, and the floor of the cave went downwardly at a slight descent.

The Professor suddenly restrained the boys. "Wait a moment; the light behind us should be brought forward to this point."

George went back and brought it up, and after some delay a place for it was found. The two lights now plainly showed a sudden enlargement in the area of the cave, and above them hung what appeared to be huge icicles, giving the interior a weird appearance. Still no water was in sight.

"The white substances we see all around us indicate that above us the rocks are limestone, and water, in coming through, has acted on the stone so as to form carbonate of lime, or chalk."

The single lamp was now sufficient to light up the interior, which looked like a domed iceberg, with all sorts of fantastic figures standing out in bold relief, which were contrasted by the many dark recesses irregularly scattered about everywhere.

"I see an opening beyond," was Harry's remark, in a suppressed tone.

The contracted opening was to the left, and he quickly made his way over the uneven floor to that point. "The water is beyond, and I hear something there."

George quietly moved forward. The light from the Professor's lamp glistened on the surface, and rippling waves were easily distinguished.

"What has become of the light we had on the perch?" was the Professor's startling inquiry.

The boys looked back. It was not there. Probably it had gone out.

"We must not go on until we have relighted it," was the Professor's caution.

George went back. The light from the Professor's lamp still threw its rays back to the ledge, which was not more than a hundred feet from their present location. "I can't find it. It is not here, and I know I put it on this ledge. Here is the piece of lime I put up against it."

Too startled for words, Harry drew back from the opening. Without further conversation he and the Professor retraced their steps toward George, who was now frantically searching every crevice.

"That is too bad. Are you sure this is the place?"

"I am positive of it."

The boys looked at the Professor. He knew they mentally asked whether they should proceed with the single light. "I think it would be unwise to go farther with one light only. If we can do no better we can make a half dozen lights, and light up the whole cave. I am just as much interested in it now as you are."

They were about six hundred feet from the mouth of the cave, as nearly as could be estimated.

"Before we return we might as well chart the cave, so we shall have some idea of its crooks and turns. Have we anything to measure with? If not, have you a cord, so we can get some idea of distances?"

George held out one of the spears, which was about five feet long.

"That will answer," said the Professor. "Let us call this five feet long for the present. The first thing we must do is to establish a base line. But what shall we do for something to mark our chart on? I haven't a bit of paper."

Here was another difficulty. It would be impossible to make tracings on their clothing. Harry's wit came to the rescue. "I have it. Why can't we break off a piece of this chalk. Probably we can find some smooth piece that will answer."

"That might be done," was George's answer, on reflection; "but what can be used to mark on chalk?"

The Professor was now highly amused. "Can't you think of anything we have here which will answer?"

"I haven't had a pencil, or anything except charcoal, since we touched this wonder island."

"We have something here that is used among all civilized people the world over for marking purposes." The boys opened their eyes in wonder. "I have it here," said the Professor, looking at the lamp.

"The lamp?"

"No, not the lamp, but what is in the lamp."

"The oil? Where can we get anything to mark with in the oil?"

"We have been making a marking material all the time we have been in the cave, and you are just as well acquainted with it as anything you know. It is the soot from the burning oil."

The boys laughed, not at the information, but at their stupidity.

"Yes; the soot is carbon, and the best soot is made by imperfectly burning oil, or fat, or any other fuel which has a large amount of carbon."

The boys found several pieces of flat chalk, one of them a little over a foot long. This was held above the flame of the candle until covered with soot.

"The first thing to do is to establish a base line. This we will mark A on the drawing. Now, starting from the point here where we lost the light, you may measure along the line to the west, we will say, until you get to the other end of the chamber. Twenty-five measures of the spear? That makes the chamber 125 feet long, and it is about 90 feet the other way. Let us roughly outline the floor plan. Now go out toward the mouth of our cave, and measure off 50 feet. Stop there. You see, I have marked the line A and have laid down the slate slab so that this line is exactly on a line with the one you have measured along the chamber. The point B, 50 feet from here, which you have just measured, makes an angle, C. I will now take the slab to the point B, and you may measure off 50 feet more, and we will call that D. That gives us another angle line, E. You see, at every point we establish a new base line. C is the base line for the line E, and so on all through the cave."

* * *

Fig. 32. The Cave, and how it was charted.

* * *

All the measurements were made on the plan outlined, and scratched on the sooted slab.

"One thing more we must observe. As we are marking the successive points, you will notice that I took particular care to observe the side walls of the passageway, so that I could roughly outline them, noting the distances from the various points, and in a crude way marking out the irregularities between the points."

The chart interested the boys so intensely that the disappearance of the light did not again recur to them until they emerged from the mouth of the cave, when it all came back again, with added wonder and speculation. How many more mysterious things would present themselves!

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