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 hoard 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 illustrated in Fig. 82. The bolt was then passed 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.

Fig. 80. Cutting Out a Disk.

Fig. 80. Cutting Out a Disk.

Fig. 81. The Sighting Disk

Fig. 81. The Sighting Disk.

Fig. 82. Nut Fastened in Block.

Fig. 82. Nut Fastened in Block.