e advertisements is most significant. It shows that whoever prepared
these advertisements was high in the confidence of the German
government. Only the very topnotch spies are likely to be permitted to
know the diplomatic code."

"And you think, then, that Otto Hoff may be the head of the conspirators
in this country?" said Jane.

"Not Otto--Frederic," said Fleck quickly. "The young man, I am certain,
was the director, probably sent out from Berlin after the country became
too hot for Von Papen and Boy-ed. The old man, I believe, merely carried
out his orders. I doubt even if they are uncle and nephew."

"I think you are wrong about that," protested Jane. "Whenever I was
listening over the dictograph it was always the old man who was so
bitter against America. It was he who talked about the wonder-workers
and the necessity for haste. I never heard Frederic say
anything--anything disloyal, that is."

"The fact that he knew enough to keep his mouth closed shows that he is
the more intelligent of the two. Don't forget, too, that at times he
even dared to don the uniform of a British officer. You saw him
yourself. Undoubtedly he is the more dangerous of the pair."

"But who read these advertisements?" asked Jane, seeking to change the
subject. "For whom were the bulletins intended?"

"It was one of their ways of keeping in communication with their
thousands of secret agents all over this country. I wouldn't be
surprised if occasionally these advertisements were printed in Texas
papers and shipped over the border into Mexico. We have been watching
the mails and the telephone and telegraph lines for months, yet all the
while Mexico has been sending messages across, telling the U-boats
everything they needed to know. We never thought of checking up the
advertising in papers in the Mexican mail."

"But what about the messages old Mr. Hoff left in the bookstores? Was
that part of the plan, too?"

"It may have been simply a duplicate method of communication in case
the other failed. The Germans here know that they are constantly watched
and take every precaution. We'll land that girl as soon as we have the
Hoffs safe behind the bars, and then we'll soon see if Carter's
dachshund theory was right."

"But who," asked Jane, "is the spy in our navy? Who signalled the Hoffs'
apartment and supplied them with the news about our transports? Was it
Lieutenant Kramer?"

"Probably," said Chief Fleck carelessly, "that is not my e