The Scientific American Boy Part 7

This, as shown in Fig. 94, was merely a board fastened with four rope strands to the ring of the tackle block. A single rope was used, with the ends tied firmly together. The loop thus formed was pa.s.sed through the ring of the tackle block and the opposite ends were twisted over the ends of the seat board in the manner ill.u.s.trated in Fig. 95. The tackle blocks were quite small, having 2-inch sheaves, and they, together with the large pulley or "traveling block," as we called it, cost us about $2.50. Two light ropes were fastened to the large traveling block, each rope long enough to reach across the stream. The ropes extended to opposite anchorages, where each was pa.s.sed over a branch of the tree and belayed on a cleat within easy reach. A fellow could draw himself up clear of the ground by pulling on the free end of the fall, as a painter does; then tying the swing fast in this position, he would pull himself across the stream by means of the rope stretched to the opposite anchorage. The swing could be drawn back by the next one who wanted to cross. We also used this aerial line for transporting loads from one island to the other.

[Ill.u.s.tration: Fig. 96. The Rope Railway.]

SUSPENSION BRIDGE.

[Ill.u.s.tration: Fig 97. Barrel-stave Flooring.]

[Ill.u.s.tration: Fig. 98. The Suspension Bridge.]

Our aerial railway didn't last long. We soon tired of it, and instead utilized the materials for a rope suspension bridge. We procured from Lumberville half a dozen old barrels and used the staves as a flooring for the bridge. The staves were linked together by a pair of ropes at each end woven over and under, as indicated in the drawing Fig. 97.

Notches were cut in the staves to hold the ropes from slipping off. The flexible flooring thus constructed was stretched across the river and secured to stakes driven firmly in the ground. A pair of parallel ropes were extended across the stream about three feet above the flooring, with which they were connected at intervals of five feet. The bridge was 25 feet long, and while rather shaky, owing to the fact that there were no braces to prevent it from swaying sidewise, still it was very strong and did excellent service.

PONTOON BRIDGE.

[Ill.u.s.tration: Fig. 99. The Pontoon Bridge.]

At the head of the mill-race, where the channel was fifty feet wide, we built a pontoon bridge. We were fortunate in securing six good cider barrels at low cost, also a quant.i.ty of "slabs" from one of the sawmills of Lumberville. "Slab" is the lumberman's name for the outside piece of a log which is sawn off in squaring up the sides. We made a raft of these materials and floated them down the river to Lake Placid. The bridge was made by anchoring the barrels in the channel about eight feet apart, and laying on them the floor beams, which supported a flooring of slabs. The floor beams were narrow planks 1 inch by 4 inches, taken from the bridge wreck, and they were placed on edge to prevent sagging. Of course we had no anchors for securing the barrels, but used instead large stones weighing about 100 pounds each, around which the anchor lines were fastened. We found it rather difficult to sink these improvised anchors at just the right places, for we were working at the very mouth of the mill-race, and were in constant danger of having our scow sucked down into the swirling channel. Once we were actually drawn into the mill-race and tore madly down the rus.h.i.+ng stream. By Bill's careful steering we managed to avoid striking the sh.o.r.e, and just as we were off the Tiger's Tail Reddy succeeded in swinging a rope around an overhanging limb and bringing us to a sudden stop. A moment later we might have been dashed against the rocks in the rapids below and our boat smashed. Shooting rapids in a scow is a very different matter from riding through them on a plank.

THE KING ROD TRUSS.

Our bridge building operations were not entirely confined to the island.

Two of them were built on the Schreiner grounds at Lamington. Reddy Schreiner's home was situated a little distance above the town where Cedar Brook came tumbling down a gorge in the hills and spread out into the Schreiners' ice pond. Thence it pursued its course very quietly through the low and somewhat swampy ground in the Schreiners' back yard.

Over this brook Reddy was very anxious to build a bridge. Accordingly, before returning to school in the fall Bill made out a careful set of plans for the structure, and after we had gone the rest of the society, under Reddy's guidance, erected the bridge.

[Ill.u.s.tration: Fig. 100. The King Rod Bridge.]

The structure was a cross between a suspension bridge and a spar bridge.

The banks of the stream were so low that, instead of resting the floor of the bridge on top of the inclined frames, as we had done over the mill-race, it was suspended from the spars by means of wires. The crossing ends of the spars were nailed together and their lower ends were firmly planted about four feet apart in the banks of the brook. A stick nailed to the apex of each pair of spars served temporarily to brace them apart. The center cross beam of the bridge was now suspended from the spars by means of heavy galvanized iron wire (No. 14, I should say). The beam was hung high enough to allow for stretch of the wire, making the roadway incline upward from both sides to the center. Aside from carrying the floor of the bridge, this beam was used to brace the inclined spars when the temporary crosspiece was removed. The ends of the beam projected about thirty inches beyond the bridge at each side, and they supported braces which extended diagonally upward to the crossing ends of the spars. When this was done the temporary crosspiece above referred to was removed. As the span between the center cross beam and the banks was a little too long to provide a steady floor, a couple of intermediate cross beams were suspended from the inclined spars. The floor beams were then laid in place and covered with a flooring of slabs.

STIFFENING THE BRIDGE.

The bridge was a pretty good one, except for a slight unsteadiness between the center and either end. When Uncle Ed saw it he showed us at once where the trouble lay. Our intermediate cross beams were hung from the center of the spars, and consequently made them bend, because the strain came across their length, while at the center of the bridge there was no chance for the spars to bend, because the strain was exerted along their length, that is, it tended merely to push the ends of the spars deeper into the banks. To remedy the trouble he proposed propping up the center of each spar with a brace running from the center crosspiece. The dotted lines in Fig. 100 show how these braces were applied. They made the floor perfectly solid throughout, and gave the bridge a much better appearance. Uncle Ed told us that the structure might be called a "king rod truss," except that in place of rods we had used wires.

[Ill.u.s.tration: The King Rod Bridge.]

[Ill.u.s.tration: The Bridge over Cedar Brook Gorge.]

THE KING POST BRIDGE.

The other bridge on the Schreiner property was built in the following summer, just before we started on our second expedition to Willow Clump Island. It spanned the brook at the gorge, and was therefore a more difficult engineering feat. Mr. Schreiner himself asked us to build it, and we felt greatly honored by the request. A search was made in the Van Syckel library for a suitable type. At last we found one that seemed properly suited to the requirements. It was called a "king post truss,"

and was very similar to the king rod bridge. While the design of the bridge was simple, yet it required some ingenuity to put it together. In setting up the other bridge the scow had been anch.o.r.ed in the center of the stream and used as a working platform, from which it had been an easy matter to put the various parts together. In this case our scow was obviously of no use, so we laid a couple of long logs across the chasm, and a few slats were nailed across them to provide a temporary bridge or working platform. The platform sagged considerably at the center, because the span was fully eighteen feet; but the logs were large, and we knew they were strong enough to support our weight. However, as an extra precaution, we tied the ends to stakes driven in the ground, so that they could not possibly slip off the banks.

[Ill.u.s.tration: Fig. 101. The King Post Frame.]

[Ill.u.s.tration: Fig. 102. The King Posts Set in Position.]

[Ill.u.s.tration: Fig. 103. The Permanent Cross Beam Made Fast.]

First we set about constructing the king posts, which were made as shown in Fig. 101. Two stout posts 7 feet long were connected at the top by a tie stick, which s.p.a.ced them 4 feet apart. To make a secure fastening they were notched together and strengthened with diagonal braces. Each king post was notched on opposite sides, at about thirty inches from the top. A temporary tie piece was also nailed across the lower ends of the king posts. The frame thus formed was set up at the center of the span and temporarily held by nailing the lower tie piece to the working platform. Four stout spars were now cut, each about fifteen feet long.

Taking a pair at a time, we planted their lower ends firmly in the opposite banks and sawed off their upper ends until they could just be hammered into the notches in the king post. This required careful fitting, but by making the spars a little too long to start with, and then shaving them down with a draw-knife, we managed to make fairly good joints. A couple of long wire nails in each spar made the structure perfectly secure. The king posts were now sawed off just above the temporary tie piece, and the permanent cross beam was fastened to these ends with straps of heavy wire wound tightly about them. The working platform sagged so much that we were able to lay this cross beam above it. From the ends of the cross beam diagonal braces extended to the king posts (Fig. 103). Our working platform was now removed and replaced with the permanent floor beams, which were firmly nailed to the center cross beam and to the inclined spars at the sh.o.r.e ends. The floor beams were quite heavy and needed no support between the king posts and sh.o.r.e. A rustic floor was made of small logs sawed in two at Mr. Schreiner's sawmill. Light poles were nailed to the flooring along each edge, giving a finish to the bridge. We also provided a rustic railing for the bridge of light poles nailed to the king posts and the diagonal spars.

CHAPTER X.

CANVAS CANOES.

Like all inhabitants of islands, we early turned our attention to navigation. Our scow was serviceable for transporting materials back and forth across the strips of shallow water between our quarters and the Jersey sh.o.r.e. We never attempted to row across, because progress would have been entirely too slow, and we would have drifted down to the rapids long ere we could reach the opposite side. But on Lake Placid matters were different. Although there was no settlement near us on the Pennsylvania sh.o.r.e, to occasion our crossing the water for provisions and the like, yet the quiet stretch was admirably suited to boating for pleasure, and mighty little pleasure could we get out of our heavy scow.

UNCLE ED'S DEPARTURE.

Owing to a sudden business call Uncle Ed left us after he had been with us nearly three weeks. But, before going, he explained carefully to Bill just how to construct a canvas canoe. Jack, the cook, who was anxious to lay in a second supply of provisions, accompanied Uncle Ed as far as Millville, the next town below Lamington. Here Uncle Ed bought five yards of canvas, 42 inches wide, several cans of paint and a quant.i.ty of bra.s.s and copper nails and tacks. These supplies, together with the food provisions that Jack had collected, were brought to us late in the afternoon by Mr. Schreiner. Mr. Schreiner also brought the necessary boards and strips of wood for the framework of our canoe.

A VISIT FROM MR. SCHREINER.

We invited Mr. Schreiner to spend the night with us, and this he did after fording with some difficulty the swift-running river. In the morning we showed him our quarters, our filter, the roads we had built, the spar bridge across to Kite Island, our surveying instrument and the chart we had made of the vicinity. He was greatly pleased with our work, and it was then that he gave us an order for the bridge over the gorge.

From that day on he became our staunchest ally, so that when my father and Mr. Van Syckel complained that we were loafing away a lot of time which could be more profitably spent in study or work, Mr. Schreiner stood up for us and declared that our experiences on the island were doing us far more good, both physically and mentally, than any other work that they could conceive of; that before condemning us they should pay us a visit and see how we were employing our time.

THE SAILING CANOE.

[Ill.u.s.tration: Exploring the River in the Indian Canoe.]

[Ill.u.s.tration: Fig. 104. Stern Post of the Canoe.]

[Ill.u.s.tration: Fig. 105. Stern of the Canoe.]

[Ill.u.s.tration: Fig. 106. Center Form.]

[Ill.u.s.tration: Fig. 107. Bulkheads.]

[Ill.u.s.tration: Fig. 108. Center Braces.]

[Ill.u.s.tration: Fig. 109. Top View of the Canoe Frame.]

[Ill.u.s.tration: Fig. 110. Side View of the Canoe Frame.]

Immediately after Mr. Schreiner's departure we started work on the canoe. A strip of spruce 1 inch thick, 3 inches wide and 12 feet long served as the keelson. At the stern a post 1-1/2 inches thick, 3 inches wide and 13 inches high was secured to the keelson with bra.s.s screws.

This was braced as indicated in Fig. 104. At the bow a stem piece was attached to the keelson. This stem was cut to a somewhat semicircular form, as shown in Fig. 105. The outer edge was tapered with a draw-knife to a thickness of 1/4 inch and a brace was nailed to the inner edge. Our next work was to cut out three forms, one of the shape shown in Fig. 106 and two like that shown in Fig. 107. The first form was set up on the keelson midway between the stem and stern, and the other two were s.p.a.ced about four feet each side of the center form. The center form was used only for shaping the frame of the boat, and was not intended to be permanently affixed to the canoe. Therefore, we fastened it to the keelson very lightly, so that it could be readily removed. The other two forms, however, were made permanent parts of the frame, serving as bulkheads. The gunwales were now secured in position. These were of spruce 3/4 inch thick and 2 inches wide. The ends were beveled off so as to neatly fit the stem piece and the stern post, to which they were fastened by bra.s.s screws. Then we applied the longitudinal strips, or rib bands, which were of 1/4-inch thick spruce 1 inch wide. Ten of these bands were used, equally s.p.a.ced apart on the center form, to which they were lightly tacked; but they were nailed securely to the bulkheads and the stem piece and stern post. The cross ribs were made of barrel hoops which we had soaked in water for a day or so to render them pliable enough to be bent into place. These hoops were split to a width of 1/2 inch, and secured first to the keelson, then to the longitudinal strips and finally to the gunwales. Copper tacks were used for nailing the ribs in place, and these were long enough to be pa.s.sed through the rib bands and clinched on the outside. Forty cross ribs were nailed on, and at the center of the canoe they were s.p.a.ced about three inches apart. The center form was then removed and cut along the dotted lines shown in Fig. 106. The semicircular pieces thus obtained were now strengthened with strips on their inner edges, and wedged in between the keelson and the gunwales, to which they were nailed, as shown in Fig. 108. A pair of cleats nailed to the cross ribs served as supports for the seat of the canoe. The frame of the boat was completed by nailing in place two deck beams of 1/2-inch square pine and four corner pieces between the gunwales and the bulkheads, so as to make an elliptical well hole or deck opening. Before laying on the canvas covering the edges of the gunwales, keelson, deck beams, stem and stern posts were smoothed down with sandpaper.