that will tell which way the
wind blows--it might be the print of a shoe in the earth or something
like that. Lots of ways to pick up information, if only you keep your
wits at work."

"Yes," returned Andy, "and if it's Frank Bird who's doing the
thinking. But perhaps it would be silly in me sleeping out here tonight.
I'd better be traipsing back to bed right now, because, you see, I'm
only half dressed and it's chilly."

"Good. I'll see you to the house, because I've got to walk home, now
that my wheel has gone up the flume," remarked Frank.

"What's the matter with you using mine?" demanded the other. "That plug
you put in holds dandy, and there's nothing the matter with it right
now. Same old place, under the side porch here. Guess the lamp is on the
bum, but you hardly need that. If a cop holds you up, explain what
happened."

"All right, I guess I might as well ride as walk. But I hope I get my
wheel back. It's nearly new, you know, and cost a heap," Frank remarked,
as he dove under the stoop, to presently appear dragging the other
bicycle.

"Apply to Puss and Company for further information," called Andy,
holding the door open a crack to shoot the words out and then closing
it.

Frank, laughing at the obstinate ways of his chum, pushed the machine
out to the road and was soon moving along. Evidently he lacked the same
confidence in Andy's wheel that he felt in his own, for he made no
attempt to speed as he went toward town and home.

Fortunately he met no policeman, who might ask impertinent questions as
to just why he was riding after dark without a light. And reaching home
he found his father sitting up in his office waiting to hear his report.

Dr. Bird was quite satisfied with what Frank had to say in regard to the
condition of the sick girl. He knew that the boy was well up in
medicine, even though he had never tried to push him in the least. Frank
gave evidence of being what is known as a "natural born doctor," keenly
alive to everything pertaining to surgery. More than once he had set
broken limbs for dogs and cats and done it in a manner that aroused the
warmest praise from his father, who, deep down in his heart, knew the
boy had it in him to become a famous surgeon, if he kept along in this
path when he came to take up his life pursuit.

Frank believed he ought to tell about the dastardly attempt to destroy
the monoplane. And, of course, the good doctor, who always thought the
best of people