. It went beautifully as far as the bridge, but was too
light to run much beyond. The next time we loaded it up with stones and
had the pleasure of watching it sail down hill, across the bridge and
vanish out of sight around the shore of Kite Island. That was
demonstration enough. We knew it would carry us safely and it did. The
next time we tried it four of us piled into the small car, and in a
moment we were off on a most thrilling ride, which ended right in front
of the log cabin, where the car came to a sudden stop after riding off
the end of the rails and plowing through the sand for a short space.

CHAPTER XXV.

THE CANTILEVER BRIDGE.

There is one more piece of work done by our society which yet remains to
be described, and that is the cantilever bridge. This we all voted to be
the greatest of our achievements on the island. To be sure, it was Uncle
Ed's design, but I think we justly deserve credit for the masterful way
in which it was erected. In our search for types of bridges before
building the king post bridge, we came across a simple cantilever bridge
that didn't look very difficult to construct. To be sure, none of us
knew a thing about stresses and strains, and ingenious though we were,
Bill realized that the task of designing a cantilever bridge was far
beyond him. Nevertheless, we were sure we could build one if only we had
a good set of plans. A letter was therefore mailed to Uncle Ed, asking
him for the required details. The answer came promptly from Western
Australia, asking us to send him the exact width of the water we wished
to span, the depth of the water, the distance from the top of one bank
to the top of the other, and the exact height of the banks above water
level. We decided we would build the bridge across the mouth of the
lagoon. The distance here between the two banks measured a little over
60 feet. The banks were very precipitous, and rose 13-1/2 feet above the
level of the water. All these details, together with soundings of the
bottom, all the way across, were sent to Uncle Ed, and on the day after
our railway was completed quite a bulky package was received in answer.
It contained complete directions for building the bridge of wooden
frames, which were so designed that they needed merely to be hooked
together to form the bridge, though to make the structure perfectly safe
Uncle Ed cautioned us to tie the frames together wherever they met.

I am half afraid to tell my reade