by?" said the colonel.

"Yes, sir. Unless they've located us precisely on advance information.
I don't see how they could find us among the mountains in all this
darkness and rain."

"But they've had the advance information! Look there!" exclaimed Major
Hertford, pointing toward the high ridge that lay on their right.

A beam of light had appeared on the loftiest spur, standing out at first
like a red star in the darkness, then growing intensely brighter, and
burning with a steady, vivid light. The effect was weird and powerful.
The mountain beneath it was invisible, and it seemed to burn there like
a real eye, wrathful and menacing. The older men, as well as the boys,
were held as if by a spell. It was something monstrous and eastern, like
the appearance of a genie out of the Arabian Nights.

The light, after remaining fixed for at least a minute, began to move
slowly from side to side and then faster.

"A signal!" exclaimed Colonel Newcomb. "Beyond a doubt it is the
Southerners. Whatever they're saying they're saying it to somebody. Look
toward the south!"

"Ah, there they are answering!" exclaimed Major Hertford.

All had wheeled simultaneously, and on another high spur a mile to the
south a second red light as vivid and intense as the first was flashing
back and forth. It, too, the mountain below invisible, seemed to swing
in the heavens. Dick, standing there in the darkness and rain, and
knowing that imminent and mortal danger was on either side, felt a
frightful chill creeping slowly down his spine. It is a terrible
thing to feel through some superior sense that an invisible foe is
approaching, and not be able to know by any kind of striving whence he
came.

The lights flashed alternately, and presently both dropped from the sky,
seeming to Dick to leave blacker spots on the darkness in their place.
Then only the heavy night and the rain encompassed them.

"What do you think it is?" asked Colonel Newcomb of Major Hertford.

"Southern troops beyond a doubt. It is equally certain that they were
warned in some manner from Washington of our departure."

"I think so, too. It is probable that they saw the light and have been
signalling their knowledge to each other. It seems likely to me that
they will wait at the far end of the valley to cut us off. What force do
you think it is?"

"Perhaps a cavalry detachment that has ridden hurriedly to intercept us.
I would say at a guess that it is Turner Ashby and h