"There's something funny here," he said. "But, no matter what
happens pretend you think it's all right. Let anyone who speaks
to us think we're foolish. It will be easier for us to get away
then. And keep your eyes wide open, if we stop anywhere, so that
you will be sure to know the place again!"

"Right!" said Dick.

Just then the cab, caught in a rutty road where the going was very
heavy, and there was a slight upgrade in addition, to make it
worse, slowed up considerably. And Dick, looking out the window
on his side, gave a stifled exclamation.

"Look there, Harry!" he said. "Do you see the sun flashing on
something on the roof of that house over there? What do you
suppose that is?"

"Whew!" Harry whistled, "You ought to know that, Dick! A
heliograph - field telegraph. Morse code - or some code - made by
flashes. The sun catches a mirror or some sort of reflector, and
it's just like a telegraph instrument, with dots and dashes,
except that you work by sight instead of by sound. That is queer.
Try to mark just where the house is, and so will I."

The cab turned, while they were still looking, and removed the
house where the signalling was being done from their line of
vision. But in a few moments there was a loud report that
startled the scouts until they realized that a front tire had
blown out. The driver stopped at once, and descended, seemingly
much perturbed. And Harry and Dick, piling out to inspect the