wonderful contrivance make a start, and expecting the greatest treat of
their lives, when that event occurred.

Such experienced workers as the two Bird boys had now become would find
little or no trouble about carrying out the work they had on hand. Every
steel wire guy was kept as taut as a fiddle string; and by the time they
were done handling the aeroplane it would be in apple-pie shape for
work.

"Did they smash much in the shop, Frank?" Andy asked after they had
been working some little time, and making fair progress.

"Why, no, it didn't seem to me that they took the time to do great
damage; and that's why I fancy they were scared off, somehow or other.
They went in a hurry, or else they would never have forgotten those
things. And when I looked around I made up my mind that they were just
mad because they didn't find our machine at home, and so tried to let us
know that fact."

"Perhaps it was a second detachment of the same crowd that came out
here?" suggested Andy, speculatively.

"Tell me, what would they be doing with electric torches, and black
masks? Now, you can see that these have been pretty well used; they're
not new ones just cut out by pattern at home with mother's scissors.
These have been made by an experienced operator, and were bought either
for a mask ball or some other purpose."

"Well, perhaps we'll never know the truth about it," grumbled Andy, who
never liked anything to puzzle him and would lie awake half the night