THE HIDDEN MESSAGE
While the work of getting out the planking for the boat was going on,
and the plowing had now been resumed, since the new yoke of oxen were
fitted to do the work, the boys were not forgetful of the usual weekly
outing. They had several quite important things right at home which
needed looking into, if they wanted to solve some of the things on the
island. First, the cave, which they had twice attempted to explore; the
search for their lost boat, which had the strange rope and oars; and the
mystery of the flag and pole.
These things weighed heavily on their minds, because these happenings
were close at hand. But what made the greatest impression on the minds
of all was the finding of the _Investigator's_ lifeboat. It seemed
almost like a call to them from the interior. The impatience of the boys
was almost beyond restraint, at times.
"It does seem to me that we should not delay an hour in making some
effort to explore the direction the boat came from," was George's view
of the situation as they canvassed the subject.
"That is my idea, also, and I am not in favor of giving much more time
to hunting or other forms of recreation until we know how that boat came
to South River."
"Yes; I can appreciate how anxious you are," said the Professor, after
the boys had given their views. "What we are doing, however, is
essential from every point of view. We must prepare provisions, so that
we shall be able to know where we can get them in case of need. On the
other hand, weapons are necessary, which take time to construct. If,
however, it is thought advisable, we might make a trip of explorations
along the South River, beyond the falls, the time to be limited to a
week; but I have my doubts of the wisdom of such a course."
This suggestion appealed strongly to the boys, who were always keen for
anything which savored of adventure, and it was some time before the
boys could reconcile themselves to the saner and more business-like
course of completing the boat and making the trip by water.
The weather was beautiful, and vegetation was springing up in abundant
profusion everywhere. Magnificent showers fell at intervals, and the
rainbows, more beautiful than any they had ever heretofore seen, spanned
the heavens after the showers.
This had been noticed during the previous year, but now, after nine
months of their life, with the wonderful insight which their needs had
instilled into them, made them very observant of every phenomenon.
"I have often wondered," observed George, as he gazed at the beautiful
broad band which formed a crescent across the heavens, "why there are
never any rainbows in the middle of the day. They are never seen except
in the morning or in the evening, and usually only in the evening."
"In order to understand that it will be necessary to explain what a
rainbow is. As I stated previously, light is merely vibration. Now
colors are formed by the different lengths of the vibrations, just the
same as the different musical notes are made by the different vibratory
lengths. To understand this more fully, I make a sketch (Fig. 7), which
shows just what I mean. You will see that red is the lowest musical
pitch, which we will call C, and to the right is a long, wavy line. D,
the next pitch higher, might resemble orange, with the wavy line a
little shorter, and so on, until we reach the highest note in the scale,
where the wave lengths are very short. You have probably noticed that a
drop of water in the sunshine glistens, and, if closely observed, may
have seen that it was colored, particularly blue or green. As the rays
of the sun strike the globe of water, they produce different wave
lengths, and in that way make it appear to you as being possessed of
colors. Now, a rainbow is nothing more nor less than sunlight passing
through the drops of water which are suspended in the air and causing a
refraction of the light. At noon the sun shines down from overhead, and
we are not in the proper position to see this refracted light; but in
the morning or in the evening the sun shines against the earth at an
angle. At those times we are able to see the effect of refraction by the
colors produced.
[Illustration: _Fig. 7. THE COLOR SPECTRUM_]
[Illustration: _Fig. 8. REFLECTION ANGLE_]
"When you throw a ball against a wall at an angle, it bounds away at the
same angle. That is reflection, and is just exactly what light does when
a ray strikes a mirror. If, on the other hand, the glass had no mercury
on it to reflect the light, the ray would not go straight through, but
would bend, just as you have seen a stick in a glass of water appearing
as though it was bent below the water line. That is refraction."
Two weeks of very vigorous work had now been put in since the yaks had
disappeared, and the wagon was still at the edge of the forest. George
was anxious to recover it, with the new team, and with Harry started out
early in the morning to make up as much as possible lost time, as every
hour was considered valuable in their enterprises.
The yaks could be ridden as well as horses, but the greater part of the
way were driven. One of the guns which had been completed was taken
along, as well as the only pistol which the Professor had saved. In less
than three hours the forest was reached and they were soon within sight
of the wagon.
"What have we there?" cried Harry, as they neared the spot.
"Our yaks! And where do you suppose they have been?"
Close by the wagon were the yaks, as though patiently waiting for the
boys. They made no resistance, nor show of fright, when the boys
approached. One of them, Jack, still had the strap tied to the horns,
and it was the halter which had been attached to the tree at South
River.
A hasty examination was made, but if either of the boys came to any
conclusion concerning it, nothing was said. Without wasting time, the
team brought with them was yoked up and the broken wheel replaced by a
new one. The repairs to the wagon tongue did not take long, and they
were ready for the return.
"What shall we do with Jack and Jill?" Those were the names bestowed on
the first team. "Let us see if they will follow us."
They had gone fully one hundred feet before the yaks made any sign, and
then slowly followed, thus assuring them that no care or attention would
be required in that direction. Both boys were intensely delighted at the
recovery of their favorites and could not get home fast enough to give
the Professor the good news.
Nearing home, the Professor, who was on the watch, came out to meet
them, waving his hat at the sight of Jack and Jill. When the latter came
up he went over and affectionately petted the creatures, who seemed to
realize the welcome.
"I hope they are as glad as we are; I can understand why they got away;
look at the end of this thong." It plainly showed the teeth of some
animal which had gnawed the leather of which it was made.
"So you have been out prospecting, too?" was Harry's query, as he saw
the queer-looking reeds on the table in the laboratory that evening.
"What do you call that?"
"Our honey has been getting low, and I took the occasion to-day to bring
in some samples of sugar."
"Is that sugar cane?"
"Yes; the true sugar cane."
"Is that different from sorghum?"
"This is the species which grows in the southern part of the United
States. The kind you know and which is cultivated in the Northern
States, is the Chinese Sorgo, or, as we call it, sorghum. It is equal in
quality and in quantity to the southern species and is readily treated
to produce molasses or sugar."
"What is that peculiar flower, if it is a flower? I never saw a flower
like that; it seems to be hard."
"I was surprised to find this. It is called the Tamarisk. This long,
oval-shaped part is made by an insect which inhabits the plant, and is
eaten by the inhabitants in the plains east of the Mediterranean Sea. It
is there called Mount Sinai Manna, and is supposed to be the Manna which
the Jews found when they were in the Wilderness after the Exodus."
"I think we have properly named this place Wonder Island."
In the volume preceding this, when they first considered the building of
a new boat, it was decided to graft an extension to the after part of
their wrecked lifeboat; but when the second one was found, and
calculations were made as to its usefulness, it was discovered that such
a course would not be wise; hence the larger vessel was found to be the
only solution.
The newly discovered boat was, however, a valuable addition, as it
afforded a means by which short trips could be made, and Harry quietly
set to work making a sail and rigging up a mast, so that the
long-cherished desire to make these trips could be undertaken before
they were ready to launch the real vessel. It was hauled up on shore and
caulked and new parts added to make it adaptable for the purpose.
While engaged at this work he removed the cross seat which still
remained, and in doing so was surprised to find a piece of cardboard
which had been hidden, apparently, at the end of the board. Eagerly
picking it up, he saw writing on it, with the following words: "We
cannot hold out much longer. Wright and Walters were captured yesterday.
WILL."
[Illustration: _Fig. 9. THE HIDDEN MESSAGE_]
Harry could hardly contain himself, as he rushed up to the laboratory,
crying out: "George, come here, quickly! I have found something!"
Without waiting to see whether George heard, he rushed into the
Professor's den with the paper in his outstretched hand. "Look at this;
don't you remember Will Sayers? I am sure it is Will."
George heard his excited voice, and appeared without any delay.
"What is it now?"
The Professor was reading the scrap, and silently handed it to George.
"Did you know either of the boys mentioned in this?"
Neither had any recollection of Wright or Walters, but they inferred
that the writer must be Will Sayers, one of the companions. The
Professor had no recollection of the boy, nor could he remember the
other names.
"Let us examine every part of the boat," was the Professor's first
suggestion. "We may find something more to give some clue."
The boys rushed down to the beach where the boat was moored, the
Professor following.
"Show us the exact location of this strip."
"I had just taken off this cross seat, and as I did so this piece fell
from the end."
"Let us put it back again and see how it fits into that place."
When it was replaced they noticed that a crack was left at each end of
the seat, not exceeding an eighth of an inch.
"It is very plain that the piece you found was at this end, and if it
was folded as this crease indicates, it could have been concealed there
and thus escaped our observation." After some minutes' examination, he
continued: "This piece must have been there for some time."
"Why do you think so?"
"You will notice that the end of the board has the marks of the folded
paper, showing it must have been in its place of concealment for some
time. Furthermore, the paper itself indicates that it has been there for
some time, by the discoloration on its outer side."
"How long do you think it may have been there?"
"It is impossible to say; but certainly for several months."
"Doesn't it seem reasonable," Harry inquired, "to think it was some one
from the _Investigator_? Otherwise, how is it that they had possession
of the boat?"
"That is the problem we shall now have to find out."
Thus, in another direction, was found an evidence that savages were on
the island and that others had been wrecked and found a refuge there.
How much of a refuge it was to them they had no means of knowing. They
were thankful their own lives had been preserved and had been permitted
to accomplish so much during their enforced stay.
"We are now vigorous and strong and have been blessed with energy as
well as health. It is our first duty to take up the task of finding our
comrades, whatever the cost may be. If that is your view, we should
proceed with that determination, but let us prepare for it in the best
manner possible. How long will it take to finish the six guns you are
now at?" said the Professor, looking at Harry.
"I will try to have them ready within another week," was his reply.
"In the meantime, George and I will prepare a new lot of powder; and for
your further information, I will state that I have been busy during the
past week in making preparations to extract some lead for bullets."
This announcement was hailed with joy. Heretofore they had to depend on
the iron slugs which had been turned out, and they were not at all
satisfactory, because they lacked the proper weight.
"Which is the lead?" asked George, who was examining the samples.
"It is this bluish-gray sample of galena, which, as you see, looks like
lead itself, and is often mistaken for it; but it is far from being lead
of the kind we can work."
"Why not?"
"Because it is in what is called a sulphide form. Do you remember what a
sulphide is?"
"Yes; it is where it is in combination with something."
"That is a fairly good definition. More or less sulphur is found in all
metals, but when found in large quantities the ore is called a
sulphide."
"How can we get rid of the sulphur?"
"We can cook it and drive it off like steam. Lead melts at a low
temperature, comparatively, about 600 degrees Fahrenheit, so that with
our furnaces it will be a very easy matter to get a pure lead."
During the rest of the day all were in the laboratory, superintending
the preparation for the work, and at the Professor's suggestion the boys
took the team in the morning and brought in over a hundred pounds of
galena to be treated.
Before noon they had forty pounds of a very fine quality lead, and the
work of making molds for the bullets was begun. The Professor, however,
suggested that the boys should devote their time to the construction of
the boat and guns, and it was difficult to decide what was the proper
thing to do first.
The Professor saw the dilemma and had a very earnest conference on the
subject.
"You must not, by any means, be carried away with undue eagerness and a
desire for haste. The first essential of good business is to do
everything in order. It is better to plan carefully every step in
advance, so that you will know just when your energies will be required
for the next step. An eminent engineer, on one occasion, in answer to a
question as to why he was always prepared for an emergency, laid down
this rule: Whenever you have a problem to solve, work it out in more
ways than one. If one fails, you can apply the other immediately.
This can be done without a moment's delay. Therein lies the
answer--preparedness."
The boys readily saw the force of the lesson. From that time on it was
not necessary to direct the order of events. Each saw to it that the
part allotted to him was carried out in a determined spirit.