The upper connecting spars were wedged
tightly under the cross sticks, and served as an additional support for
them. Diagonal braces were nailed from one frame to the other, as
illustrated in Fig. 318. The towers were built on opposite banks, at the
mouth of the lagoon, and when completed we lowered them carefully down the
banks into the water. According to directions they were to be set just 30
feet apart, measuring from the center of one tower to the center of the
other. The water was quite shallow where the towers rested, but the bottom
was pretty firm. Holes were dug in the bottom for the legs of the tower to
set into, and then large stones were piled around each leg to provide a
firm foundation for the towers.
[Illustration: Fig. 317. Notching the Sticks Together.]
Setting Up the Frames.
[Illustration: Fig. 318.
View of Part of the Bridge, with Letters Indicating the Various Frames.]
A B frame was now hauled out to one of the towers and lifted by its
narrower end, with fall and tackle, until its lower tie piece rested on
the projecting ends of the center crosspieces of the tower. The upper end
of the frame was held against the top of the tower, while a C frame was
hooked over the upper ends of the tower legs; then frame B was allowed to
swing outward until its smaller end locked with the outer end of frame C.
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