Part 10 (1/2)

”Let me step it off,” said Harry. ”I find it is just two and three-quarters inches.”

”What was the distance, in feet from A to B?” asked John.

”I have the figures here,” said George. ”We found it was six hundred and ninety feet.”

”If, now, you will multiply 690 by 2-3/4, we shall have the distance from this point A, and yonder point, or headland C.”

[Ill.u.s.tration: _Fig. 6. The Second Limb._]

”I make it out to be just 1897.5,” was Harry's conclusion.

The boys, together with John and a half dozen of the natives, went along the sh.o.r.e, and mounted the point C, and from that place selected another point in a southerly direction, and again made the same calculations.

The vessel in the meantime was put under sail and anch.o.r.ed a mile below, giving the surveying party time to make several triangulations, and late in the afternoon the party came on board, tired and ready to take a rest.

From the position taken up by the s.h.i.+p they could see a long stretch of sh.o.r.e line, practically straight, trending toward the southeast, and with their gla.s.s could see, miles away, a headland which afforded a p.r.o.nounced point for observation.

The next morning the same parties rowed to the sh.o.r.e, and Uraso was left with the party to guard the sh.o.r.e boat, while Muro accompanied John and the boys. On this occasion John issued the following instruction:

”The long point which you see in the distance is, probably, 15 miles beyond. It is not more than that, but this clear atmosphere is liable to deceive. I have instructed Sutoto to wait until one o'clock today, and if by that time there is no word from us Uraso will return to the s.h.i.+p, and you will take up anchor and steer for the headland beyond.”

”So that you may understand our movements, we will strike into the interior, taking a course due east, for ten miles, or thereabout, and then turn to the south, and reach the sea near the place where the vessel will be located.”

”I understand, now, how the distance can be measured by triangulation on land; but how to get the distances, on s.h.i.+pboard, is what puzzles me,”

said Harry.

John smiled as he replied: ”I knew you would come to that sooner or later, so I prepared a little sketch (Fig. 7), which shows the bow of a vessel, and the tall mast. The lines from A to B give an angle with the vertical line of the mast, which will enable you to determine how far the s.h.i.+p is from any point.”

”But I am still in the dark as to how, even if we have that distance, we can thereby tell by triangulation, on the vessel, how far one point is from another on the land.”

[Ill.u.s.tration: _Fig. 7. Triangulation from a Vessel._]

”After the distance from the vessel to the point is determined, as I have shown, then the length of the s.h.i.+p itself is used as the two points to sight from, and the two lines thus projected, from the opposite ends of the vessel, together with the line lengthwise along the s.h.i.+p, form a triangle, the same as the triangle lines 1, 2, 3, in the sketch (Fig.

5).”

It might be well at this place to describe the equipment of the party as it left the boat. The natives carried a plentiful supply of provisions.

Each had a gun, the best kind of breech loaders, and also a spear.

The natives love to handle spears better than anything else in the way of a weapon, and each also had a knife, and some carried the inevitable bolo, that primitive form of hatchet which is known all over the world where steel or iron is available, and the people have arrived at such a state that they are able to make metal articles.

John and the boys also carried guns, but the boys had revolvers, seven shooters, not of large bore, but very convenient weapons, in close quarters. Each carried also a knife, and belt to contain the cartridges for the guns.

Harry carried a camera, which he had brought from the States, and George had the field gla.s.s strapped across the shoulders. John felt that they had a force large enough to make a fairly effective stand against a pretty strong force of natives, the entire party counting, in this instance, sixteen.

As they advanced into the interior, it was evident that they were gradually ascending, so that at about six miles from the landing place they reached the crest of the rising ground. Beyond, where the nature of the ground permitted they saw clearly that the distance beyond had a lower alt.i.tude than the place where they stood.

During this trip there was no evidence that the island was occupied, but they saw the most amazing evidences of tropical fruits and trees.

Magnificent trees were in evidence everywhere, and the woods, besides mahogany, and ebony, were of the most valuable character.