The Scientific American Boy Part 5

He arranged us about five feet apart in a line extending from the filter to the river. We had six pails, and these Dutchy filled one at a time, pa.s.sing them up the line to Reddy, who emptied them into the upper barrel and then threw them back to Dutchy to be refilled. Working in this way it did not take long to fill up the filter, and the burden of keeping the barrels full, instead of falling on one person, was shared alike by all.

[Ill.u.s.tration: Fig. 70. Filling the Barrel.]

THE KLEPALO.

Our camp outfit was further augmented by a dinner call. We discovered the necessity of such a call on our very first day of camping. Dutchy was so excited by his discoveries of the morning that he started out alone in the afternoon to make a further search. The rest of us were lazy after the noon meal, and were lolling around taking it easy during the heat of the day, and discussing plans for the future. But Dutchy's energetic nature would not permit him to keep quiet. He took the scow and waded with it against the strong current to the deeper and quieter water above the island. Then he rowed a long way up stream. He was gone all the afternoon. Supper time came and still he didn't appear. The sun was high, and I presume he didn't realize how late it was getting.

Finally, just at sunset, he came drifting down with the current, tired and hungry, and ready for a large meal. But we had finished our supper an hour before, and poor Dutchy had to be content with a few cold remnants, because the cook had declared he wouldn't prepare an extra meal for a fellow who didn't have sense enough to know when it was meal time.

Then it was that Uncle Ed bethought himself of the _klepalo_.

"You ought to have some sort of a dinner call," he declared, "so that any one within a mile of camp will know when dinner is ready."

[Ill.u.s.tration: The _Klepalo_.]

"Did you ever hear of a _klepalo_? No? Well, I was down in Macedonia a couple of years ago inspecting a railroad, and I stopped off for the night at a small Bulgarian village. The next day happened to be a _Prasdnik_, or saint's day, and the first thing in the morning I was awakened by a peculiar clacking sound which I couldn't make out.

Calling my interpreter I found out from him that it was a _klepalo_ for calling the people to church. The people there are too poor to afford a bell, and so in place of that they use a beam of oak hung from a rope tied about the center, and this beam is struck with a hammer, first on one side, and then the other. Sometimes an iron _klepalo_ is used as well, and then they strike first the beam and then the iron bar, so as to vary the monotony of the call. I found that the wooden _klepalo_ could be heard for a distance of about one and a half miles over land, and the iron one for over two miles. Now we can easily make a wooden _klepalo_ for use in this camp, and then if Dutchy, or any of the rest of us, keep within a mile and a half of camp there won't be any trouble with the cook."

So we built a _klepalo_, getting from Lumberville a stick of seasoned oak, 1-1/2 inches thick, 6 inches wide and 4 feet long. A hole was drilled into the stick at the center, and by a rope pa.s.sed through this hole the beam was suspended from a branch overhanging the camp.

Jack, the cook, regularly used this crude device to call the hungry horde to meals.

CHAPTER VII.

SURVEYING.

One of the first things we did after getting fairly settled in our new quarters was to make a complete survey of Willow Clump Island and its immediate surroundings. Our surveying instruments were made as follows:

THE SURVEYING INSTRUMENT.

[Ill.u.s.tration: Fig. 71. Baseboard of the Surveying Instrument.]

[Ill.u.s.tration: Fig. 72. Sighting Blocks on the Baseboard.]

Out of a 1-inch board we cut a base 15 inches long and 4 inches wide. In the center we sawed out a circular opening of about 3 inches diameter and covered this at the bottom by a circular piece 1 inch thick and 5 inches in diameter, thus forming a socket in which our compa.s.s fitted snugly. A hole 1 inch in diameter was drilled through the center of this circular piece to receive the pivot pin of a tripod. Across each end of the baseboard we secured a block 4 inches long, 2 inches wide and 1 inch thick. A 1-inch sight hole was drilled through each block at its center.

A ring of cardboard, on which Uncle Ed marked with radial lines the 360 degrees of the circle, was placed over the compa.s.s socket, with the zero and 180 degree marks pointing toward the sight blocks. The outer faces of the end blocks were now wet with mucilage and a hair was stretched vertically across the center of each sight hole. The hairs were then adjusted by sighting through the holes and moving the nearer hair sidewise until it was exactly in line with both the zero and the 180 degree marks on the cardboard. Then a hair was stretched horizontally across the center of each sight hole. Great care was taken to place the hairs at exactly the same height above the baseboard. To protect the hairs after they were adjusted, they were covered with a piece of gla.s.s, which was secured in place by tacks driven into the wood with their heads projecting over the edges of the gla.s.s.

SPIRIT LEVELS.

From one of his pockets Uncle Ed produced two small bottles, the kind used for holding homeopathic pills. These he filled nearly to the top with water, corked them and wedged them into grooves cut lengthwise in the baseboard at opposite sides of the cardboard ring. These grooves were filled with putty, and to make sure that the bottles were level with the baseboard the latter was floated on a bit of quiet water and the bottles were pressed down at one end or the other until the bubble within rested at the exact center.

THE TRIPOD.

[Ill.u.s.tration: Fig. 73. The Tripod Head.]

[Ill.u.s.tration: Fig. 74. The Tripod Leg.]

[Ill.u.s.tration: Fig. 75. The Surveying Instrument Complete.]

[Ill.u.s.tration: Fig. 76. The Protractor.]

The tripod head was formed of a wooden disk 5 inches in diameter, with a wooden pin projecting from its center adapted to engage the hole in the circular piece above referred to. To the bottom of the tripod head were nailed three blocks 2 inches long and 1 inch square in cross-section.

The tripod legs were made of light strips of wood, 3/8 inch by 1 inch by 5 feet long, which we secured from one of the mills at Lumberville. Each leg was formed of two of these strips, nailed securely together to within 20 inches of the top. At the upper ends the strips were spread to receive the blocks on the tripod head. In this position they were held by headless wire nails driven into the ends of the blocks and fitting into holes drilled in the strips. For a plumb line we tacked a cord to the center of the tripod head, and attached a good-sized sinker to its lower end. In connection with this plumb line we occasionally used a protractor consisting of a semicircle of cardboard 5 inches in diameter, on which the degrees of the circle were marked off with radiating lines, as ill.u.s.trated in Fig. 76. By holding the straight edge of this protractor against the base of the tripod, and noting the number of degrees between the 90 degree mark and the plumb line, we could tell at a glance at what angle from the horizontal the instrument was tipped.

SURVEYOR'S CHAIN.

[Ill.u.s.tration: Fig. 77. The Surveyor's Chain.]

[Ill.u.s.tration: Fig. 78. Forming the Links.]

[Ill.u.s.tration: Fig. 79. A Double-Ringed Link.]

We made a surveyor's chain of wire links, each 12 inches long, instead of 7.92 inches, which is the length of a standard surveyor's link. The wire we used was No. 16 galvanized iron, which was rather stiff and difficult to bend. In order to make all the links of exactly the same size and shape we used a form, around which they were bent. The form consisted of a 1-inch board in which two 1/2 inch holes were drilled, just 11-1/2 inches apart, measured from their centers. An oak pin, 1/2 inch in diameter, was driven into each hole and projected about an inch above the board. Two blocks of oak were secured to the baseboard, just before each pin, as shown in Fig. 78. This form gave great satisfaction.

A groove was cut in the side of one of the pins to receive the ring of a completed link, while the wire was pa.s.sed through this ring and bent around the peg to form the ring of the new link. After each link was formed it was carefully measured, and, if too long, was shortened by flattening the rings endwise, or, if too short, was lengthened by pinching together the sides of the rings. There were fifty links in our chain, and every tenth one was formed with a double ring at the end, so as to distinguish it from the rest (see Fig. 79).

THE SURVEYOR'S ROD.

[Ill.u.s.tration: Fig. 80. Cutting Out a Disk.]

[Ill.u.s.tration: Fig. 81. The Sighting Disk]

[Ill.u.s.tration: Fig. 82 Nut Fastened in Block.]

We completed our outfit by making a surveyor's rod out of a straight stick of wood about 6 feet long. A target or sighting disk was mounted on the stick. This disk was 6 inches in diameter, and was sawed out of a 6-inch square board by making straight cuts across the corners and then smoothing off the edge to a perfect circle with a draw-knife. The thickness of the disk was only 1/2 inch. At the back of the disk we fastened a block of wood with a slot cut in it to receive the rod, as shown in Fig. 81. To hold the disk at different heights on the rod a small bolt was used. The nut on this bolt was slipped into a hole on the block at the bottom of the slot and held in place by driving in nails about it, as ill.u.s.trated in Fig. 82. The bolt was then pa.s.sed through the hole and threaded through the nut, with its inner end bearing against the rod. The disk could thus be held at any desired position by tightening up the bolt. A piece of white paper was now pasted over the disk. The paper was marked off into quarters, and opposite quarters were painted black so that it would be easy to sight, from a distance, the exact center of the target.

A SIMPLE METHOD OF SURVEYING.

Of course, none of us had studied trigonometry, but Uncle Ed devised a very simple method by which we could determine distances quite accurately without much figuring.

"If you will tell me the length of one side of a triangle and the angles it makes with the other two sides," said Uncle Ed, "I'll tell you the length of the other two sides and the size of the third angle. This is how I will do it:

[Ill.u.s.tration: Fig. 83. Diagram of Our First Lesson in Surveying.]

"Say the line is 6 inches long and one angle is 35 degrees, while the other is 117 degrees. Let us draw a 6-inch straight line. This we will call our base line. Now we will place the base edge of our protractor on the base line with its center at the right hand end of the line. At the 37 degree mark we will make a dot on the paper so, and draw a line from the right hand end of the base line through this dot. Now we will do the same thing at the opposite end, making a dot at 107 degrees from the line, and draw a line from the left hand end of the base line through this dot.

"If we extend these lines until they intersect, we will have the required triangle, and can measure the two sides, which will be found to be about 12 inches and 8 inches long, and the third angle will measure just 26 degrees. It doesn't make any difference on what scale we draw the triangle, whether it be miles, yards, feet, inches or fractions of an inch, the proportions will be the same. If the base line had been 6 half-inches, or 3 inches long, and the same angles were used, the other two lines would measure 12 half-inches, or six inches, and 8 half-inches, or 4 inches. If the base line were 6 quarter-inches long, the sides would be 3 inches and 2 inches long.

[Ill.u.s.tration: Fig. 84. Determining the Distance to the Tree.]