THE TERRIBLE MONSOONS
Of the two most urgent articles, namely, weapons or the boat, it was
decided that the guns should be completed first. The feeling that the
time would come when a visit from the savages might be expected at their
home, contributed to this decision.
Six barrels, each eighteen inches long, and with a bore three-eighths of
an inch in diameter, had been turned out, and several of the stocks had
been made at odd times during the evenings. As Harry had sufficient
steel left for four barrels more, two days were devoted to boring them
out, in the hope that they would ultimately be able to finish them up.
They would then have a battery of ten guns, and the necessity of having
a number arose from the fact that they were muzzle-loaders, and could
not be reloaded rapidly.
A sketch of the gun with the firing mechanism is furnished, in which it
will be seen that the firing plug travels in a bore formed through the
stock; in a line with the barrel. This plug had an upwardly extending
finger, so it could be drawn back against the resistance of the spring.
Below the plug was a trigger, with a hook-shaped forward end, in such a
position that when the plug was drawn back the hook would catch and hold
the plug until the lower right-angled projection of the trigger was
pulled back. This would release the plug, and the spring would then be
driven forward and explode the cap.
[Illustration: _Fig. 10. THE FIRST GUN_]
"It would be well," said the Professor, "to polish the inside of the
bored barrels, and thus make a much better weapon."
"How can we do this?" asked Harry.
"There are several ways, but the better plan would be to take a good
polishing material, in the form of a fine sand or grit, and mix it with
oil. This can then be put on a wiper which will snugly fit the bore, and
the barrel may then be put in the lathe and rotated at a high rate of
speed with the wiper in the bore, and during the rotation the wiper is
drawn in and out. This operation should be continued for an hour at
least, frequently withdrawing it to add more of the polishing grit."
"What is the best grit to use?"
"If we can find a sample of the adamantine spar, in sufficient
quantities, it would be the best substance."
"What kind of material is that?"
"It is a substance known as corundum."
"Is that the same as emery?"
"What is known as emery is the more or less impure product from the same
source. I think I have stated heretofore that both of these products
come from the precious gems; the blue variety is known under the name of
sapphire; the red as ruby; the yellow as oriental topaz, and the violet
as oriental amethyst."
During that and the following day the Professor spent some time in
prospecting for the gems, but if he succeeded in finding any samples he
did not make the discovery known.
A few days after this Harry announced that he was ready to lay the keel
of the new boat. All the material had been prepared, and was at the
beach. Prior to this the island had been visited by a heavy storm. They
had been frequent within the past month, but this was not considered
unusual.
The Professor insisted that a temporary shed should be erected to cover
the material, as moisture would make it very undesirable for the vessel,
and a day was occupied in putting up the structure.
An entire week thus passed, every hour of which was devoted with the
utmost diligence to the various enterprises. The keel was laid and the
work of putting on the bottom boards was progressing rapidly. One night,
a few days after the laying of the keel, a brisk wind sprang up, which
continued during the night, increasing in fury, and in the morning
evidences were seen on all sides of the effect of the tempest.
"It seems very singular," was George's observation, "that we should have
such terrible winds here."
The Professor had evidently expected the storms. "Do you remember the
experience we had less than a year ago? We had five days of this on the
ocean."
"I had forgotten that. Do they occur every year?"
"You may have heard of the monsoons, a periodical wind in the Indian
Ocean, which is a northeast wind, and they blow with greater or less
force from November to March."
"What causes them to blow with such regularity during those periods?"
"Ah! that is one of the things which it has been difficult to determine.
They appear to be modifications of the trade winds. While, as stated,
the northeast winds blow during the periods mentioned, they have the
southwest monsoons, which blow from April to October. As these violent
winds are the most tempestuous during the period when the sun crosses
the equator, it has been argued that it is due to the action of the sun
being in such a position that its rays strike the earth in the center of
its rotation, thus heating up the air and causing it to rise rapidly
along the middle belt."
"Is that what we understand by the equinoctial storms?"
"The equinoctial storms come in March and September, when the days and
nights are of equal length."
"I was told by a teacher that the summers are longer north of the
equator than south of it; is that true?"
"Yes; the summer north of the equator is about seven and a half days
longer."
"What is the cause of that?"
"The earth is at its greatest distance from the sun during the summer
months, and the angular motion of the earth in its orbit is slower. The
result is, that the interval from the March to the September equinoxes
is greater than from September to March."
Harry made his way through the violent wind and rain to the boat shed.
He came back with a sorry-looking countenance. "I am afraid everything
is soaked beyond recovery." He was almost on the verge of tears.
Before noon the rain abated somewhat, but the winds still blew strongly,
and when they ventured out to take stock of their surroundings, George
was the first to notice the disappearance of the flag on Observation
Hill. Rushing in to the Professor, he cried: "Our flag is gone."
Harry was at the boathouse, and when George went down to inform him of
the new calamity, he was almost heart-broken. The Professor, however,
was not in the least perturbed. He laughingly chided them and soon
restored the boys to their usual gay and happy demeanor.
"Such little incidents as we have met with this morning only give us
variety. We need something of this kind to add zest to life. Just
imagine what life would be if everything turned out just as you wanted
it or willed it? You would commit suicide within a week."
The boys smiled, but at the same time their eyelids did double duty in
the blinking line for a little while.
George straightened himself out and looked up the hill. "Well, I am
going for that flag whether it blows or not," and he started for the
hill. Angel, who was in the loft, swung down and made his way out of the
door, and before George had gone fifty feet, was at his heels. "And you
are going, too? Good boy!" and George actually hugged Angel. He
understood.
Arriving at the hill he made an examination, and found that the
halliards had been broken and the wind carried away the flag, halliards
and all. As the wind came from the sea, the flag must be inland
somewhere. Search was made in every direction, but to no purpose. Every
rock and lodging place was examined, but it had disappeared. Angel was
an interested searcher. He really seemed to divine George's mission. At
every bush, or rock, or other possible landing place, he would be the
first, and peer around, and look up and down, just as he had seen George
do.
The quest kept up for over an hour, and, sadly disappointed, he returned
with the news of his failure. The Professor took the loss lightly. "I
presume it is intended that we should work out our own rescue. After
all, I think that is the proper thing to do. If we depend on others we
are sure to meet with disappointment and failure. Cheer up, boys; flag
or no flag, let us do our duty."
"I don't mind the loss of the flag so much because it prevents us from
having a signal, but I hate to think that we lost so much good time in
making and putting it up."
The flag alluded to was sixteen feet long, laboriously made out of ramie
fiber, which was woven, and then dyed, and it was a hard task to haul
the pole, which was over fifty feet long, from the forest ten miles
away, to say nothing of the labor required to raise it.
As soon as the thoroughly drenched material at the boathouse could be
brought out and dried in the sun, which now came out bright and warm,
the work proceeded with renewed vigor. Late that evening the Professor
appeared at the rear of the laboratory, and called loudly to the boys.
When they appeared at the laboratory he was laughing immoderately, and
Angel stood on one of the tables with a simian grin.
"What is the matter? Has Angel been experimenting again?"
Before the Professor could answer, George caught sight of the flag.
"What! The flag! Where did you get it?"
"Ask Angel."
The boys laughed, and George actually hugged the animal, in his delight.
Did Angel know what he had done? Ask those delvers into the mysterious
realms of thought, what prompted him to search for and restore the flag?
Is that any more remarkable than the recorded tricks of dogs and many
other animals?
You know just how boys can laugh when they are really happy. Angel
imitated that laugh, and he had not been taught to do it, either. It
came without teaching.
When the Professor had wiped away some of the tears which had come from
the excess of laughter at the imitating efforts of the animal, he said:
"Did it ever occur to you why Angel has always had a solemn look? The
facial expression seldom, if ever, changes, and they rarely ever exhibit
mirth. You may imagine the condition of those animals, living in the
forests, with enemies all about them, and the struggle for existence an
everlasting one. They have never known amusing incidents as we
understand them. Naturally, the muscles of mobility in the face, which
express pleasure, never have been exercised, and those indicating fear
and anger unduly developed. Here is Angel, in a new atmosphere, where he
sees delight depicted on the countenance, and, gifted as he is, with
wonderful powers of imitation, has learned to actually laugh, and to
enjoy the scene."
"Well, Professor, as we have one of the guns polished up and completed,
wouldn't it be well to make the bullets?"
"For that purpose I suggest that we make the molds out of a metal or
alloy which has a higher fusing point than lead."
"What is best for the purpose?"
"We might make an alloy of copper and zinc."
"Oh! You mean brass?"
"Yes; that is readily cast and easily worked."
"But what shape shall we make the bullets?"
"They should be made long, with a pointed forward end."
"Why is a long bullet better than a round or globe-shaped ball?"
"There are several very important reasons. First, momentum is a prime
element in a missile. A long one contains double the metal of a
spherical one. Second, it can be made so that it will expand when the
explosion of the powder takes place."
"In what way does it expand?"
"You have noticed that the rear end of the bullet has a cavity. When the
explosion takes place the thin shell at the rear end of the bullet
expands, so that it tightly hugs the bore of the gun."
"What is the object of having it do that?"
"To give the ball the benefit of the charge of powder exploded. If it
does not fit tightly in the bore, more or less of the powder will pass
the ball, and thus the ball loses part of its force."
"What is the object of rifling the gun?"
"The object is to impart to the bullet a spiral motion, as it moves
through the air. Metals have not the same density on all sides and this
is particularly true of molded balls. As a result, when projected from
the gun, the heaviest side has a tendency to divert the ball and make it
more or less erratic in its motion, and, therefore, inaccurate. The
spiral motion has the effect of minimizing this difficulty. The cavity
formed at the rear of the projectile was devised particularly to cause
the thin lip of the bullet to be driven into the grooves formed in the
gun barrel, and by that means the boring motion was transmitted to the
bullet."
"But as we have no means of rifling our guns, there will be no necessity
of putting the cavity in the rear end of our bullets."
"We must have the cavity there, by all means."
"What for?"
"Simply because we do not want the bullet to turn around and travel end
over end after it leaves the gun."
"How does the cavity prevent this?"
"You have probably forgotten that a body travels through the air with
its heaviest end foremost. When a cavity is made it is lighter at that
end. Without the cavity, if the forward end is pointed, it will, on
leaving the gun, turn around and go through the air with the blunt end
foremost."
The molds were made, as directed, of a hard brass composition, and when
they were ready to cast them the Professor cautioned against making any
castings with the molds in any position except upright, so that any
inequality in the density of the metal would not form itself on the side
of the cast article.
[Illustration: _Fig. 11. THE BULLET_]
Quite a time had now elapsed since the last exploration of the cave
beyond Observation Hill. The Professor had spoken about it on several
occasions. For some reason he was intensely interested in doing that. In
fact, he appeared to be more concerned about that than any other of the
unknown things about the island.
The boys could not understand this peculiarity. He had never been
questioned on the subject directly, but it was evident he had a reason
for this predominating wish to continue the exploration.
George was just as much interested, but, as the sequel will show, for an
entirely different reason. Ever restless, and always willing to
undertake anything which promised to delve into hidden things, he
approached the Professor one day with the suggestion about the cave.
"I think we ought to take one day off and go to the cave."
The Professor was interested at once. "It will not do to attempt it
now."
"And why not?"
"I am afraid we could not get in very far, unless we had a boat."
"Then why not use our lifeboat?"
This suggestion met with instant favor.
"True, I had forgotten about that."
It did not take George long to reach Harry with the news that the cave
was to be explored by means of the boat. After considering the matter
for some time it was decided to put off the trip for several days at
least, principally because the late heavy rains had, in all probability,
so filled the cave that they might be stopped in their progress before
going very far.
It should be stated that when they entered the cave the first time,
water was found about two hundred feet from its mouth and that barred
their further progress. On the second trip the water had receded, so
they could go in six hundred feet before coming to the water's edge. The
late rains may have filled the cavities, thus making progress still more
difficult.
Harry was carrying forward the boat construction, and by the occasional
aid of George was bringing the hull to a completed state. While this was
being done, George was at work with the loom, slowly weaving out the
fabric for the sails. As the mast had been stepped back over six feet
from the prow, it was concluded to make a mainsail and a jib, a small
triangular sail which is attached to the forwardly projecting jib-boom.
The two sails would afford greater speed than a single sail, and that
was one consideration. The other was, that with two sails the mast would
not need to be so long, and the dimension of the mainsail could be
reduced, and still get the same efficiency.
[Illustration: _Fig. 12. THE SEA-GOING BOAT_]
The weaving of a large sail in one piece was impossible, as the loom
could turn out goods only thirty inches wide, and as it could be
operated by hand power solely, it will be seen that the sails required
not only time, but an immense amount of patience. It is no wonder that
George was anxious to take a day off at the cave, or anywhere else that
afforded a change.
While at work Angel was his constant companion. It is remarkable what a
degree of friendship and companionship grew up between the two. In the
course of time the weaving process became so familiar to Angel that
whenever George would throw the bobbin, containing the weft, through the
opening of the woof threads, the animal stood ready to pull the heddles
forward, so as to force the last weft thread up against the one
previously threaded across.