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.
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."
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."
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."
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.
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."