signaling from the Moon Mountains.

A sudden idea seemed to strike Diego at this. He called
Muley-Hassan aside and talked earnestly with him for a few seconds,
then he came up to the boy and demanded fiercely which one of them
it was that understood wireless.

Lathrop replied that he did, and the next minute wished that he had
bitten out his tongue before he had admitted it; for Diego, in a
rough tone, ordered him to sit down at the instrument and reply that
all was well at the River Camp.

"And, mind you, youngster--no tricks," he said savagely, "or I'll
kill you as dead as mutton. I understand the Morse code myself and
can tell what you are sending; and send slow so that I can get every
letter."

Lathrop was in a quandary. To refuse to sit down at the instrument
meant instant death.

He could tell that by the look in Diego's eyes and from what he had
seen of him he knew he would not stop at a little thing like a
murder to drive home a point.

The question was, did the man really understand telegraphy? If he
didn't and was only, bluffing Lathrop determined to inform Frank of
the true state of affairs. Otherwise it would do neither himself
nor the others any good to try to trick Diego.

With a prayer on his lips that the Portuguese might not have been