"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 bra.s.s 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.
[Ill.u.s.tration: _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, princ.i.p.ally 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.
[Ill.u.s.tration: _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.
CHAPTER V
THE VOYAGE FOR THE BENEFIT OF ANGEL, AND THE DISCOVERY
Within the next week the boat hull was practically completed, and now needed caulking. For this purpose the hemp, which had been found, as previously stated, was broken up, and as much of the woody portions removed as could be taken out, so as to make it available for filling in the crevices between the planking.
The mast was stepped in, and a sufficient quant.i.ty of manilla rope twisted for the sails, and also a supply put aboard for other needs. The sails were not yet completed, but they would doubtless be ready by the time the other parts were.
In one of their evening conferences George expressed his concern about the future of Angel.
"For my part I do not want to leave him behind."
"Then why not take him with us?" asked the Professor.
Harry had some doubts on this point, but George was too insistent to brook any thought of leaving him behind.
"I make this suggestion, George: Before the time of sailing it would be advisable for you to make several trips with Angel in the small boat, and see how he behaves. In some respects he would be an acquisition to us."
The boys had not forgotten how the animal, during their various trips, had been of material a.s.sistance, nor the times when nutting how Angel understood what they were after, and would climb trees and shower them down, and then gravely help to load them into the wagon; and they remembered the recovery of the flag. Such service was appreciated.
As it was, Angel was invited to take a sail. The lifeboat recovered in South River had been named No. 2, as they insisted on calling their own wrecked vessel No. 1.
No. 2 was launched. A small sail, had been rigged up, and two good oars provided for it. Angel was completely at the command of George, and when he was called and taken down to the landing in front of the boathouse, he went without any hesitancy. But to induce him to enter the boat was another matter.
Suspecting there would be some difficulty, George pulled a small jar of honey from his pocket, and silently began to eat it. Angel"s eyes blinked. It was such an unheard of thing for George to do this without extending an invitation to join. He shambled over, but George walked to the boat and sat down in it, not appearing to notice the eager look on the animal"s face.
Without further urging he stepped aboard, and George put his arm around him, as Harry, with oar in hand, pushed the boat from the sh.o.r.e. Angel was startled, and tried to get away, but soothing words soon quieted him, and before they reached the mouth of the Cataract he was leaning over the gunwale and playing with the water in the most approved boy-like fashion.
When, however, they had pa.s.sed the comparatively calm waters in the estuary, and were rounding the cliffs, poor Angel forgot his sport, and sat as one paralyzed, gazing at the sight of the waves beating against the sh.o.r.e line. George went up to him, and spoke encouragingly, and it was fully a half hour before he was restored to his usual calm. Then, apparently, he noticed for the first time the peculiar rocking motion of the vessel. Every time it swayed to the right or to the left he would give that peculiar chuckle which always indicated delight.
They went around the point to the east, and pa.s.sed down the coast in a southerly direction, going as far as the cape north and east of the mouth of South River.
"Steer for the sh.o.r.e, George; steer for the sh.o.r.e; what is that to the right?" said Harry, pointing to the beach.
"It looks like a boat, sure enough."
As the wind was coming directly from the sh.o.r.e they had to depend on the oars to bring the vessel around, and as they came in could distinctly make out the side of a boat lying among debris, in an inclined position, against a rather steep beach.
"It is our boat, Harry." The moment their vessel came alongside, Angel jumped off and leaped over to the boat on the sh.o.r.e. Evidently he also had recognized it.
"Well, isn"t this a find?"
"How long do you suppose this has been here? I am glad we gave Angel an outing."
"Shall we take it with us?"
"Yes; if we have to carry it overland," was Harry"s reply.
"Let us float it."
It was not much of a task to do this, and with a short rope it was. .h.i.tched to the stern of No. 2. Angel remained in the recovered boat, and when No. 2 was pushed from the sh.o.r.e, and the sail set, its movement did not seem to perturb him in the least, but when the oscillations again began to be perceptible, he commenced to gurgle, and George knew they had a good sailor to take with them.
The sail took a little over three hours, and as they pa.s.sed up the Cataract River, and approached their home, the boys set up a welcoming shriek, in imitation of incoming steamers, which so delighted Angel that he scampered in a delirium of joy from one end of the craft to the other. It is doubtful whether he had ever in his short life had such a glorious time, and that he remembered it his subsequent history furnishes the best evidence.