ly the
spy had fastened that on before raising the mast. Fifty feet distant
stood a tree. The spy took something from the baggage container and
walked over to the tree, where, Henry judged by the sound, he was
fastening a hook. Then the spy carried over the other end of his
aerial and fastened it to the hook. In the darkness Henry could see
nothing of the details of this outfit, but he realized that the spy now
had an aerial at least fifty feet long and well above the ground. For
short distance communication it would answer perfectly.

The spy returned to his car and got into the seat beside the driver's.
Henry wormed his way forward as far as he dared, hardly breathing,
fascinated by what he beheld. For now he could see plainly. The spy
had turned on a tiny light on his dashboard. Cautiously Henry rose to
his feet, keeping behind a thick bush, and peered over the side of the
car. The spy took a key from his pocket and unfastened a hidden lock.
The entire cowl board turned down, revealing a compact but powerful
wireless outfit. The aerial wire evidently was strung up within the
collapsing mast.

From within the cowl the spy drew forth a curious metal disc, not
unlike a spider-web, and like nothing Henry had ever seen. He did not
know what it was. He hardly breathed as he stood watching. Then the
spy took a dollar from his pocket, examined the milled edge until he
found a scratch, fitted the curious disc over the dollar, and turning
the coin in his hand, slowly began to make letters on a slip of paper
on the inverted dash. When he had finished writing, he fastened the
disc back in the cowl, dropped the dollar in his overcoat pocket, and
began to send the message he had deciphered from the dollar.

Henry leaned forward. He had no need of his own receiving instrument
to catch the letters. And he could not have used it if he had needed
it. But it was not important that he should catch the message. The
powerful sparks that were leaping across the spy's spark-gap told him
that a battery of considerable force was being used, and he knew that
Lew would catch that message away back on Staten Island. Lew had
caught the preceding message from Long Island, and it had been sent
from a distance fully as great as this. With distinctness the letters
came to Henry's ears and he realized that the man before him was an
expert operator. But the letters he heard made no sense. They would
have to be deciphered before