With the increasing wind it was growing chilly out there for one who could not warm himself with exercise.
"It's a long time, or it seems so," muttered the young engineer presently.
"Yet I'll wager that Tom is hustling himself and others on the very jump." Again the call of a night bird, and once more a sound from shore seemed to answer it.
"Real birds ?" wondered Hazelton, with a start of sudden curiosity.

"Or have I been listening to human signals?
If so, the signals can't cover any good or honest purpose." That train of thought set him to listening more acutely than before.

Yet, as no more calls reached his ears the attention of the young engineer soon began to flag.
The monotonous lapping of the waves against the stone wall, the constant splashing of water over the rocks and the steady blowing of the wind all tended to make the watcher feel drowsy.
"What on earth can be keeping good old Tom ?" Harry wondered, more than once.
It would have been well, indeed, had Harry kept his eyes turned oftener toward the shore end of the wall.

In that case he might more speedily have detected the wriggling, snake-like movement of the big negro moving toward him.
With great caution the huge prowler came onward, raising his head a few inches every now and then and listening.

The black man's nostrils moved feverishly.