The Scientific American Boy eBook

This eBook from the Gutenberg Project consists of approximately 179 pages of information about The Scientific American Boy.
dropped back to the sides of the body, he squeezed them in against the ribs, at the same time drawing upward toward the head and counting four each time, as he had done before.  But the lesson was abruptly interrupted by Dutchy, whose imagination was worked up to such a pitch that I actually believe he thought he had been drowning.  Anyway, he squirmed out of Uncle Ed’s grasp, and wouldn’t play patient any longer.  For several days after that we couldn’t persuade him to venture near deep water.

CHAPTER IX.

BRIDGE BUILDING.

Willow Clump Island was, for the most part, a trackless wilderness, and as soon as we had made our map we laid out roads to the different important points.  Our main highway ran from Point Lookout to Tiger’s Tail.  This road was made rather winding, to add to its picturesqueness, and from it a number of shorter roads branched off.

Spar Bridge.

We ran a bridge across the mill-race at its narrowest point.  This bridge was made of trees which we had cut down in making our road.  It was quite a piece of engineering, built under Uncle Ed’s guidance.  Two frames were made of the shape shown in Figs. 91 and 92.  The side sticks were 15 feet long and spaced about 10 feet apart at the base by crosspieces.  At the upper end one frame was made 6 feet wide and the other 5 feet wide.  The side and cross spars were mortised together and secured by lashing a rope around them.  To make the frames more rigid we braced them with diagonal braces nailed on.  When completed we set the frames up on opposite sides of the stream and with ropes carefully lowered their upper ends until they interlocked, the side spars of each frame resting on the cross spars of the other.  In the angles formed by the crossing side spars a center spar was laid, and a number of floor beams or spars were stretched to this from the opposite shores.  On these a flooring was spread made of saplings, cut and trimmed to the right size.  A rustic railing on each side of the bridge completed the structure.

[Illustration:  Figs. 91 and 92.  Frames for the Spar Bridge.]

[Illustration:  Fig 93.  The Spar Bridge.]

The Rope Railway.

[Illustration:  Fig. 94.  The Swing Seat.]

[Illustration:  Fig. 95.  Tying the Ropes to the Seat.]

[Illustration:  Fig. 96.  The Rope Railway.]

The mill-race was crossed further down by a rope line on which we rigged a traveling carriage.  A light manila rope was used, anchored to a tree at each side about fifteen feet from the ground.  A pulley block with a wheel or sheave 4 inches in diameter was mounted to travel on the rope.  Suspended from this block by means of fall and tackle was a swing seat.  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 passed through

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The Scientific American Boy from Project Gutenberg. Public domain.
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