oy trailed him back to the store, but
prudently kept out of sight. There was nothing to be gained by
entering the store again. Meantime Willie scrambled up to the house
and related to Lew and his captain what he had seen. And they agreed
with Roy that the problem, instead of being easier, had become more
difficult.

CHAPTER XIII

WHAT HENRY DISCOVERED

Henry, meantime, was waiting at his station with eagerness and
quickened determination. Despite his leader's generous words, Henry
felt in his heart that his last effort had been a failure. It was true
that he had made it possible to learn the identity of the driver of the
roadster, and that the secret service men had in the meanwhile been
looking up the man's record; but Henry felt that he should also have
discovered the location of the secret wireless. Now he made up his
mind that nothing should balk him in the present attempt. That neither
accident nor anything else should hinder him from accomplishing his
purpose. He would be more skilful than he had ever been before. He
would watch closer. He would follow his quarry, as silently as a
shadow and as closely. He would do all that his leader expected of
him--and more.

Thus resolving, steeling his mind to the greatest effort of his life,
Henry stood at the little window in the garage, all atremble with
eagerness. He thought he knew every inch of the spy's roadster, but
when that car finally rolled past, Henry studied it as he had never
studied anything before. Again he noted the tread of each tire and
looked for cuts or other distinguishing marks in them. As good luck
would have it, a turning wagon obstructed the roadster just as it
reached the little garage, and the roadster came almost to a dead stop.
Henry studied its running-gear, its radiator and bonnet, its dash-board
and wind-shield. And when his eyes got so far, they went no further.
The standards that held up the wind-shield were bulkier and thicker
than any other such parts Henry could remember. The difference was not
great, yet there was a difference; and like the accomplished scout he
was, Henry noted that difference and questioned it. But, like Willie
with the spider-web disc, he was completely puzzled. The enlarged
standards might mean anything or nothing. The car rolled on and again
Henry looked in vain at the number. Some part of it was always dust
covered. But Henry observed that the hidden figures were not the same
from