WORKING ON THE NEW BOAT
Early the following morning Harry sprang out of bed and hurriedly shouted: "What did we do with the lifeboat in South River? Do you remember whether we secured it when Angel came up and let us know about the team?"
The Professor and George were up in an instant. George was the first to answer. "I left it the moment Angel came up."
"I cannot remember," said the Professor, slowly, "but it seems to me, now that I think of it, we left it on the banks, and it wouldn't do to leave it there. You must go for it at once, and bring it down to the bay, even though you cannot bring it around the cliffs."
A hurried breakfast was prepared and the boys started off at an eager pace for the river. They went directly southwest, aiming to strike the river near the falls, and after passing over familiar ground, came within several miles of it, when, in going down one of the sloping descents, saw, in the distance, what appeared to be portion of the yoke which the yaks carried.
They hurried forward, and great was the delight at finding it was really one of those they had made and used for months. It was a gratification to know that the animals were east of the falls, and, probably, sooner or later, would turn up at their home. Only one of the yokes was found, but there was evidence that both of the yaks were freed, since the part of the other yoke was still attached to the part found.
The boys were glad of this, as they had such a friendly feeling for the animals that they could not but feel that to be yoked together in the forest would be a cruelty to them.
"The Professor will be glad to know this," said George. "Look at this part of the yoke, where it has been broken. I have no doubt that this is where they struck the tree where the wagon caught."
Fig. 1. The Broken Yoke
"Let us take it with us, by all means," said Harry. An examination of the yoke plainly showed where it had come in contact with bark with considerable force. "What do you suppose caused them to be so frightened as to run away?"
They quickened their steps, and soon reached the river. There, on the shore, was the lifeboat, as they had left it, and it was the work of minutes only to set it adrift, and after depositing the yoke in the bottom, the first task was to supply themselves with a pair of oars.
The first article turned out in the way of tools was a bolo, a heavy cleaver-like blade, used by many primitive tribes. This article was duplicated by them, and always carried on all their expeditions. With this several small trees were cut down, and a pair of oars fashioned for each, and within an hour they were on their way down the stream, and in two hours more had rounded the point of projecting land east of the river mouth.
"Don't let us take any more chances of losing this boat. I am in favor of taking it around, and am willing to risk the tide, whatever it may be."
Harry's suggestion met with favor on the part of George, and when the point was rounded and they were out in the ocean, the tide, although coming in, had no terrors for them, but they boldly plied the oars, and before four o'clock had rounded the cliff point, and steered the craft into the mouth of Cataract River.
The Cataract was a much smaller stream than South River, and it was on the northern side of the island; whereas South River was on the southerly side of the island. Less than a quarter of a mile from the open sea was a cataract, at which their home was located, and the cataract was utilized as the means for producing water power.
Their appearance below the Cataract was hailed with delight by the Professor, and you may be sure that when the boat was finally landed and hauled up on the beach, all of them joined in the congratulations, which was their due.
"Just to think of it. If we had the boat we made, our lifeboat and all the parts of the wreck of the other boat, we would have a pretty respectable navy," was Harry's observation, when they landed. As it was, they now had the wrecked after part of their own lifeboat, and here was the other lying alongside. They knew the history of one of them. Would they soon know why the other should have been found in the interior of the island under such peculiar circumstances?
"And where did you get the yoke?" asked the Professor, as his eye caught sight of it.
"Two miles this side of the falls."
They little knew at this time what an important bearing the finding of this boat would have on their future course, nor could they know how this little incident would be of the greatest value to some of their companions on the ill-fated ship.
They now had possession of a boat which, while it was practically unsinkable, was not of such size as to meet their demands for the intended explorations. They felt that to attempt to circumnavigate the island and take all the chances which a meeting with natives might involve, would necessitate a much larger vessel. To add to the difficulty, all the pistols but one had been lost in the last trip, and to attempt to make explorations without proper weapons would be foolhardy. If they knew one thing, with any degree of certainty, it was that the island contained savages of some description, and provision must be made for every contingency.
Harry took upon himself the task of turning out more of the weapons, and with the experience of the past four months in this line of work, concluded he would attempt a better job than simply making pistols. It was his ambition to make a firearm that would enable them to bag the largest game, and also, at the same time, carry the bullets a greater distance than the short eight-inch barrels could.
To do this it was necessary to provide longer bits, and as the design of the new guns contemplated a barrel at least eighteen inches long, the bits had to be longer, in proportion, and the making of these consumed nearly as much time as the actual drilling out of the barrels.
George and the Professor put in a great deal of time with the new team. Their knowledge of training, in view of the former experience with these animals, was such that within a week they could drive the yaks without much difficulty, although the new team was not by any manner of means as efficient as the lost one.
When the question of the kind of material for the guns came up, Harry was much concerned, as in making the barrels that length would necessarily greatly increase the weight.
"I think it would be better to make an alloy for your purposes," said the Professor, as they were discussing the matter.
"What is an alloy?"
"It is the combination of two or more metals."
"In what way does the alloy make it better than the hardest steel?"
"It is not hardness you want, but toughness. Metals have several properties, which are utilized for various purposes in the arts. Surprising as it may seem, wood has greater resisting power than diamond, and yet the precious stone is the hardest of all substances."
"But if we unite two metals are we not then making a new metal?"
"Not necessarily so. In the case of brass it is true. This is made by uniting two parts of copper and one of zinc. Both copper and zinc in themselves are very soft, and copper cannot well be polished in its pure state. Brass, however, is not only much harder, but is susceptible of a very fine polish."
"Are the alloys of all metals harder than the metals of which they are made?"
"This seems to be a universal law in the compounding of metals. Very few metals are used alone in the various arts and manufactures. For every purpose some combination has been found which makes the product better. Even coins are so alloyed. Silver and gold in the form of money would be entirely too soft, unless alloyed with some hardening metal. Some substances, like arsenic, antimony and bismuth, are too brittle to be used alone. The only metals which can be used alone are aluminum, zinc, iron, tin, copper, lead, mercury, silver, gold and platinum."
"What is bronze, of which all the ancient guns were made?"
"That is a combination of copper and tin. This product was known fully seven hundred years before the Christian era, and was used in the making of guns until superseded by the various steel alloys of our day."
"In what proportions are copper and tin united to make bronze?"
"The proportions vary greatly. Ancient Celtic bronze had 12 parts tin and 88 of copper; Egyptian, 22 tin, 78 copper; Chinese, 20 tin, 80 copper; Roman, 15 tin, 85 copper; and in many specimens lead and zinc were also used. Tin has a capacity to harden almost any metal."
"What is the best metal to harden steel?"
"Manganese, of which you will remember we have some samples; it is the most serviceable, as we have neither nickel nor chromium."
"What amount of that metal should we use to get the best results?"
"About 14 per cent. of manganese has been found the best for such purposes as would be required in gun barrels. There is a curious thing which has been discovered in uniting manganese with steel. It becomes fairly tough if 1 per cent. is used with the steel; if the quantity added is between 1-1/4 and 3-1/2 the strength and ductility decrease; but above that, up to 5 per cent., the steel becomes brittle; above 6-1/2 per cent. it again returns to ductility and toughness and its maximum strength is found at 14 per cent."
During the evenings all took a hand at cutting out the stocks for the guns, and the plans upon which they were constructed will be fully explained and illustrated in the order of the work done.
Meanwhile it must not be supposed that work on the new boat had ceased. Harry's plan, when fully worked out, provided for one twenty feet long and six and a half feet wide amidships.
The drawing (Fig. 2) shows the construction of the hull. As they had no means for doing any fancy bending of the boards, the bottom was made flat, and the sides sloping. The bottom and the sides were made in the following manner: Two stringers (A, A) were first constructed, which were made up of thin pieces nailed together, so they could be bent in the proper shape for the bottom boards, which were laid crosswise and nailed to these stringers.
Fig 2-3. Working on the new boat
For the upper edges of the sides, called the gunwale (B, B), similar stringers were provided, but they extended farther fore and aft, and amidships were fully six and a half feet apart, whereas the lower stringers amidships were four and a half feet apart. This arrangement, therefore, provided for sloping sides, and the side pieces ran up and down on the inner course. It will be understood that the sides and bottom thus formed were to be overlaid with thin boards running fore and aft, as in Fig. 2, as they had no means for matching the boards and thus putting them together tightly.
The sides were two and a half feet high. Six and a half feet from the forward end was a cross beam (C), into which the mast was to be stepped. At the stern the bottom was sloping upwardly at an angle and brackets (D) were extended back and joined at their rear ends, to which the lower end of the rudder post was attached.
Amidships a keel (E) was formed, projecting down from the bottom, this keel being, at its widest part, two feet, and tapering down to merge with the bottom, fore and aft. The cross section (Fig. 4) shows how well he had formed the vessel, proportionally.
Fig. 4. Cross Section.
In addition to the cross seats, similar arrangements for comfort were made along the sides, and beneath the side seats were spaces in which their supplies were to be placed. The space forward of the mast was entirely closed over with a roof which sloped in both directions, and here provision was made for two berths. This would also afford them protection and serve as a means to keep out the water and insure at least one dry spot for their comfort.
As usual, George had some inquiries to make about the boat. "It has always been a matter of wonder why all boats are made with the big bulging part nearest the forward end?"
The Professor's eyes twinkled. "Probably there are a great many others who have had such thoughts. There is really no reason for it. It is not known how the custom originated, except that in sailing vessels the claim is that the ship can be maneuvered more easily by such construction."
"In what way does it make it easier to handle?"
"When a ship is driven forward by the wind, all the force exerted on the sails is transferred to the forward part of the ship, hence if made narrow at its forward end it would be driven down into the water, and the hull would, therefore, be submerged more at the forward than at the rear end. Furthermore, by having a tapering rear end, the rudder has a better opportunity of veering the ship around and you can see that the bulging part, being located forward of the middle portion of the ship, acts as a sort of pivot."
"But it seems to me that none of the reasons given will apply to a steamship, and still all the ships I have seen are made in the same way as the sailing vessels."
"That is exactly what I inferred in my answer to your first question. The truth is, that in experiments which have been made, it is shown that to have the widest part of a steamer near the stern, gives lines to a hull which has less resistance than if made in the conventional way."
"I thought probably the reason for making them so was just the same as in the case of an arrow, where the heaviest part is at the forward end."
"In that case an entirely different principle is involved. A body falls, or is projected through the air, with its heaviest end foremost, because of the greater momentum in that portion."
"It is the force of a body in motion. When a body is projected through the air it meets with the resistance of the atmosphere, and this also serves to turn the heavy side around to the forward end, because the force of momentum in the heavy end is much less affected by the resistance of the air than the lighter end." (See Fig. 5.)
Fig. 5.
Fig. 6. Red Angel.
Red Angel had now been with them more than six months, and he was probably a year old. When first captured he was a scrawny infant, dull and stupid, like all of his class. He had wonderful powers in the way of imitating habits and customs. The boys were very good vocalists, and while at work Harry would sing, but George whistled. It was an amusing sight to watch Red Angel when the boys engaged in the frequent concerts at night.
But of all the screamingly funny exhibitions, the attempt of Angel to imitate whistling was the most ludicrous. The orang's lips project too much to a point, and the jaws are so narrowed that the lips will not pucker. Whenever the boys commenced their concert Angel would be on hand, and enjoyed every moment of the time, and the boys had many a concert purely for his benefit.
At the end of each concert the whistling would begin. This invariably brought Angel to the front, and his exhibitions would be given with the utmost gravity and earnestness. The invariable result would be such uproarious fits of laughter on the part of all that he would take part in the jollification, little suspecting that the laughter was at his expense.
The only sound which he could emit during these performances sounded like a high-pitched stick rattling along a pale fence; but he was inordinately proud of it. It had always been on one key, heretofore, and without variation; but this evening Angel startled himself, as he did the others, by actually sounding two additional notes. He repeated this over and over.
"I wonder if we could make him talk?" asked George, after the laughter had subsided.
"There is no reason why some tones cannot be imitated. As the orang possesses wonderful powers of imitation and has, in captivity, developed many traits, I see no reason why simple words, or sounds, cannot be taught."
"I know there are words which he does understand. Time and again I have told him things, which he seems to understand. Now see if he understands this: 'Angel, do you want some honey?'"
His attempts at whistling ceased, and in a moment more was in the kitchen. Harry, who by this time had recovered from his mirth, thought it would be a good idea to attempt to teach him.
"If canary birds and dogs can understand language, I do not see why Angel shouldn't."
"Unquestionably, any animal, by patience, will learn the meaning of sounds. Constant repetition of certain notes causes birds to repeat them. I have known dogs to perform almost anything they were told to do, although they are not able to utter a single sound of the words emitted in giving the command."
"Well, what is it that causes sound?"
"The most wonderful thing in nature is, that she manifests herself in only one way, namely, by a movement, or a motion of some kind. Vibration is the term used to designate this. Sound, light, heat, taste, smell, and everything which becomes sensible to us is produced by vibration. The movements of the heavenly bodies, swinging back and forth around the sun, like huge pendulums, the movement of the sap in trees, up and down, the beating of the heart, the winking eyelids are all motions which show energy, development, life."
"But what is it that makes us understand one sound from the others?"
"Simply the difference in the kind of vibration. There are three things which characterize sounds; namely, pitch, intensity and character. Pitch depends on the rapidity of the vibrations; intensity on the extent or the amplitude of the vibrations; and character on the substance or instrument producing them. To illustrate: When you sing a very high note the vibrations may be five thousand vibrations a second, or there may be only two thousand during that time. That represents the pitch. In singing that note you may sing it so loud that, like a pendulum, it will swing way over to one side, or it may move only a short distance. That represents intensity. If either you or George had sung that note I should have been able to detect it, whatever its pitch or intensity, because your voices are as unlike as different musical instruments, and that is character, or timbre, as the French call it."