MAKING ELECTRICITY
In order that you may get some sort of idea concerning the condition of
our little colony, at this time, it would be well to give a brief review
of the situation. When they landed on the island the year before, with
nothing but the clothing they wore, the prospect of being delivered was
not a flattering one, as day after day passed by.
Here were two boys, unused to the privations of life, with youth and
vigor, cut off from all the pleasures of manhood, surrounded by dangers,
and day after day having mysteries thrust upon them which only increased
their fears. These things necessarily must have produced an impression
much deeper than would be the case with hardened men.
In the effort to discover, produce and build the various tools, weapons,
and articles of clothing, to hunt food, and in the endeavor to learn
about the condition of the island, and guard themselves against foes
which might be all about them, imposed immense responsibilities.
In their struggles were personified the contests of the human race from
the beginning of the world, in the effort to conquer nature, and to make
it contribute to their necessities.
The Professor knew how such a condition would tend to make active minds
either productive of good, or to fly out in the opposite direction and
cultivate the low and sordid instincts. Occupation, work, the
utilization of the mind, and above all, to direct their energies into
useful channels, had been the Professor's one absorbing aim.
The boys had responded, as all boys will, not for the love of gain or
for power or glory. Our boys had none of these. Other boys do not need
them any more than those on Wonder Island. What they do need is a true
stimulus for work; and when that evening they were gathered together in
the cozy little living room at the Cataract, the Professor who for two
days had been particularly reticent and retired, said:
"Can you imagine the condition of the pirates who gathered all that
hoard in the cave? What do you think their aim was in life?"
"It seems to me," was Harry's reply, "that the only thing they were
after was wealth."
"If what we see in the cave is any indication, the principal thing they
lived for was to kill somebody," was George's conclusion.
The answers made him smile. "You have, I presume, answered the question
in the two sentences. But there is something that you haven't mentioned,
which is at the bottom of it all."
"Yes; wanting to kill to get the money."
"That only states your previous answers in a more concrete way. There is
one word which describes it accurately: Selfishness. When a man inquires
into the secrets of nature; when he tries to turn the knowledge gained
into account, either for money or glory; when he consistently devotes
his days to labor, and his nights to thoughts to find out how he may do
something better, or quicker, or cheaper, it might all be denominated
selfishness, and so it is, in a way. It is a selfishness, however, that
does no injury to a fellow-man. That kind of selfishness is the great
quality which has produced the wonderful things that we see all about
us, and which distinguishes the man from the brute creation."
"But I have read of a great many men who made millions and millions and
who never did any of the things you have just referred to," answered
Harry.
"Then do you think they are any better than the pirates were?"
Notwithstanding the exciting times, food was a necessity, and it had to
be found and prepared. It could not be bought. All the gold in the cave
would not purchase a single meal. More barley had to be ground and the
stock of honey was almost exhausted. Their duties in the shop,
consequent on the haste exhibited to get the boat and weapons ready,
contributed to the low state of supplies.
George announced that there was less than two pounds of the honey left,
and proposed that a trip be taken to the flats, where the Professor had
found the sugar cane. All joined in the journey to the cane field, and
Angel was invited to join, which invitation was accepted by him
gleefully.
The bolos were taken for the purpose of cutting the cane, and on the way
George's inevitable question point was in evidence. "What did people use
for sweetening purposes before cane was discovered?"
"Honey was the principal source of the world's sweets. But cane is not
the only kind of vegetable from which the principle has been extracted.
There are many kinds of reeds which furnish a sweetish substance. Sugar
cane was first made known in eastern Europe by the conquest of Alexander
the Great. Nearchus, one of his admirals, in sailing down the Indus,
found the reed, and it was, previous to that time, known throughout the
greater part of India. He described it as a kind of honey growing in
canes and reeds. From this you may infer that honey was the principal
source of sweets in his time."
"What are the other principal plants or substances that sugar is made
from?"
"Mainly from beet, tubers of various kinds, such as the common dahlias,
and numerous vegetables, from milk, fruit, gum arabic, as well as fish."
"I have heard it said that sugar contains all that is necessary to
sustain life. Is that true?"
"That is a mistaken idea. It will sustain life for quite a time and with
the addition of nitrogenous matter has great fattening properties, but
without that it is not valuable as food."
"What do you mean by nitrogenous matter?"
"Meat, fish, eggs, milk, beans, peas, and the like, all contain a large
amount of nitrogen."
"I remember my arm being burned on one occasion, and mother made a syrup
out of sugar and put it on. In what way was the sugar beneficial?"
"In the first place, sugar is one of the most powerful antiseptics
known. It acts, therefore, as an aid to healing, since it protects the
wound from foreign substances and from poisonous and harmful germs. In
the next place, it is a great preservative for either fruit or flesh."
The cane was cut close to the root, and the top and leaves trimmed off.
Within several hours a full load was thus procured. The boys enjoyed the
pith, and George playfully gave some to Angel. His surprise knew no
bounds. When he knew what the cane was good for, he simply gorged on it.
[Illustration: _Fig. 16. Cane Crusher._]
Harry at once set to work on turning up two rollers from hickory, the
rollers being eight inches in diameter, and eighteen inches long, and
each being provided with a spindle four inches in diameter. One end of
each of the spindles was longer than the other, so pulleys could be
attached, the object being to provide a means whereby they might be
turned by suitable belts from the water wheel. In addition, the top
roller was made so it would yield, and had levers resting on the
spindles, and provided with weights, so the rollers would press out the
juice, whatever the quantity that might be placed between the rollers.
It was really a simple little machine to put up, but it required a day
for both of them. Vessels were now provided for the juice, and when they
were filled, the Professor suggested that a little lime should be put
into the juice, after it had been strained through the ramie cloth.
"What is the object of putting in lime?"
"To precipitate the impurities."
The action of the lime was plainly visible, and after it had been
allowed to settle, the clarified portion was drawn off, and the process
of boiling down was proceeded with. As fast as one of the vessels was
boiled down, more of the cane was crushed, the juice being dipped from
one vessel to the second one, until the entire load was crushed and the
juice boiled down to a thick consistency.
Here was molasses, at any rate a good substitute for honey, and it was
so homelike to get the real article. That night they had molasses candy.
It felt like old times. It was a real candy pulling, and no one enjoyed
it more than Angel. From the moment he had the first taste of the pulp
of the cane, he was the most interested one of the party. But the fun
came the next morning, when George brought out, for his benefit, some of
the taffy which had been set out to harden. The chuckle which he
emitted, when he tried to pry off a piece of the sweet morsel, was too
amusing for words.
When the entire amount of juice had been boiled down and it had readied
the point where it had the appearance of granulating, the fire was
withdrawn, and the whole mass stirred until it was cooled, and the
result was a fine sample of beautiful brown sugar which weighed
forty-three pounds.
Nevertheless food was an important item in their preparations, the
necessities for doing everything in their power to insure the success of
the maritime enterprise. One of the most valuable adjuncts for sailing
is a compass. No attempt had been made to produce the implement, and
when the needs of the expedition were being discussed, Harry was curious
to know the reason why the compass always pointed north and south.
The Professor was very much interested in all electrical phenomena and
replied: "The earth is a huge magnet, and any body which is magnetized
has a north and a south pole. The needle which is also a magnetized body
has, in like manner, a north and a south pole."
"But in what manner does that make the needle point in one way only?"
"Electricity is a very curious thing. While the current unquestionably
moves from one end to the other of a conductor, it also exhibits itself
in the form of rings around the wire. This may not be understood in the
absence of a sketch. For that purpose I make a drawing (Fig. 17) which
shows a conductor (A), through which a current is passing, and this
current is represented by the spiral line (B) which goes around the
conductor."
[Illustration: _Fig. 17. A MAGNET_]
"Well, is magnetism the same as electricity?"
"Both exhibit the same manifestations. Magnetism is nothing more than a
body charged with electricity. The electricity, which appears to travel
around the conductor (A), extends out for some distance from its body,
and produces what is called a magnetic field. This is the case whether
the magnet is a permanent one, like the earth, or whether the conductor
is charged by a dynamo."
"What is the difference between the north and the south pole?"
"There is really no difference. The terms north or south and positive or
negative are mere relative designations, and are distinguished simply by
the movement or direction of the travel of the current. You will
remember when we made the battery, it was shown that the current,
outside of the battery, moved from the positive to the negative pole.
That was merely stating that it moved from the north to the south pole
outside of the earth, and from the south to the north pole inside of the
earth. The current is, therefore, from one magnetic pole to the other."
"What I cannot understand is why the magnetic poles should be at the
north pole and at the south pole."
"The magnetic poles are not at the poles of the rotation of the earth,
but hundreds of miles away, to one side of the poles on which the earth
rotates; but they are near enough to the real poles, for all purposes,
so that the needle points to what we call the north pole of the earth.
Any magnetized body must have these two opposite poles. If it is a body,
like a bar of iron, one end is called north and the other south. Look at
this other sketch (Fig. 18) and you will see how the currents flow in
the two magnets. In this case the large body (E) represents the earth
and the small body (M) the magnet. Now notice that the current going
around the large body moves to the right, or to the north pole, whereas
the current in the small magnet (M) flows in the opposite direction."
[Illustration: _Fig. 18. MAGNETIC INDUCTION_]
"And does the current flowing around the bars, as you have shown, make
the small magnet turn around so that it is always parallel with the
large magnet, and make the north pole of one magnet at the same end with
the south pole of the other magnet?"
"Yes; to make it still clearer, I make two more drawings (Figs. 19 and
19a), in which two sets of magnets are shown. In the first of these
pairs of magnets (Fig. 19), the two north poles approach each other, and
the two south poles are opposite each other. The currents, if you will
notice, at the north poles move toward each other, and at the south
poles move away from each other. They are, therefore, acting against
each other, and the result will be that the magnets will move away from
each other. If, now, one of the magnets is turned so the poles of one
magnet approach the opposite poles of the other magnet, as shown in the
second view (Fig. 19a), they will attract each other, because the
current is permitted to flow through the two magnets in the same
direction without one conflicting with the other."
[Illustration: _Fig. 19. Fig. 19a. THE TWO MAGNETS_]
"Is that the reason it is stated that likes repel and unlikes attract?"
"Yes."
In order to take advantage of this knowledge, knowing that the earth is
a great permanent magnet, it was necessary to make a small magnet, and
so suspend it that it would turn freely, and the magnetic north and
south could then be determined.
To do this the battery which had been previously made was brought into
play. George took a hand in the work, and while they were preparing the
metal for the little bar, said: "You spoke about a permanent magnet.
What other kinds of magnets are there?"
"Magnets are permanent or temporary. A permanent magnet is one in which
the electricity resides, or remains, as it does in the earth. A
temporary magnet is one which has magnetism imparted to it only while a
current of electricity is passing around it."
"How is the current made to pass around it?"
"By wrapping an insulated wire around it, and sending a current through
the wire. When that is done the same thing is done to the bar as the bar
of the permanent magnet exhibits. As soon, however, as the current
through the wire ceases, the bar is again demagnetized. That is, it
ceases to be a magnet."
"We have the small bars ready, Professor. What is the next step?"
"It must be hardened so as to make it a flinty steel. The harder the
better, so that it will preserve the magnetism imparted to it."
"Is that the better way to make the temporary magnet?"
"No; in that case the bar should be of the softest iron. Remember,
therefore, that for a permanent magnet, use the hardest steel, and for a
temporary one, the softest iron."
"Then as we want to make a permanent magnet, must we harden both of the
bars?"
"No; for our uses, one must be left soft, because on that we shall want
to wind some insulated wire to make a temporary magnet."
The small amount of wire which was on hand was then coated with a thin
layer of the ramie fiber, which was carefully wrapped around, so that
the different layers of wire could not touch each other. When this was
completed, a spool was constructed, which fitted over the little bar or
rod, because they were rounded off, and one end of the soft iron rod
extended out beyond the spool.
The opposite ends of the winding were then brought out and attached to
the terminal wires of the battery. A test showed that the magnet thus
made would readily pick up pieces of iron or steel. The Professor then
took the hardened steel rod, through which a small hole had been bored,
midway between its ends, and laying it down on the table, the projecting
end of the temporary magnet which projected from the spool was put into
contact with the hard steel rod, and slowly drawn along to the end. The
soft bar magnet was then raised up and again repeated, as shown in the
drawing (Fig. 20), where the dotted line (A) represents the movement of
the end of the temporary magnet.
[Illustration: _Fig. 20. MAKING A PERMANENT MAGNET_]
This was repeated over and over a great many times, and finally the hard
steel bar was found to have a charge of magnetism, and for the purpose
of providing a means for holding the magnetism, a C-shaped piece of iron
was put on the bar, as shown in the detached figure.
"Is that the reason," asked Harry, "why a small piece of metal is always
put across the ends of a horseshoe magnet when it is not in use?"
"Yes."