THE DISTANT SHIP AND ITS DISAPPEARANCE
"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."
[Illustration: _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.
[Illustration: _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."
[Illustration: _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 it 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."
[Illustration: _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!