This done, we took two sticks of 3/8 inch wood, 1 inch wide
and 3-1/2 inches long. In the upper end of each stick a slot was cut 1/2
inch deep and 1/4 inch wide. Into these slots the trunnions of the mirror
were placed, and then the nuts were screwed tightly on, clamping the
sticks against the sides of the mirror. The sticks were now connected by
nailing a 1/2-inch strip at the bottom, and braced by a couple of corner
pieces. This formed a swiveled frame for the mirror, which was clamped to
the base of the instrument by means of a bolt 1-1/2 inches long. The bolt
passed through the bottom board of the frame, squarely under the peep hole
of the mirror and through the baseboard of the instrument near one end.
The baseboard was 2 inches wide, 10 inches long and 3/4 inch thick.
The Sight Rod.
[Illustration: Fig. 155. The Sight Rod.]
[Illustration: Fig. 156. Nut Set in Baseboard.]
At the end opposite to where the mirror frame was swiveled we mounted a
sight rod, which was merely a round stick of wood 1/2 inch in diameter and
about 8 inches long. We cut the stick from one of the rounds of an old
broken chair. The upper end of the rod was whittled to a point and one
side was flattened as shown in Fig.
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