“It looks significant to me,” said Warner thoughtfully.  “A mile or two farther up, this stream, so I’m told, makes an elbow, and beyond that it comes with a rush out of the mountains.  Its banks are lined with woods and thickets and some of the enemy may have slipped in and launched these chips.  I’ve a sort of feeling, Dick, that it’s really your cousin and his friends who have done it.”

“I incline to that belief myself,” said Dick.  “You know they’re ready to dare anything, and they don’t anticipate any great danger, because we don’t care to shoot at one another, until the campaign really begins.”

“At least,” said Warner, “it’s best to apply to the problem a good algebraic formula.  Here we are in a wood, some distance from our main camp.  Messages, bearing a warning either in jest or in earnest, have come floating down from a point which may be within the enemy’s country.  One of the facts is x and the other is y, but what they amount to is an unknown quantity.  Hence we are left in doubt, and when you’re in doubt it’s best to do the safe thing.”

“Which means that we should go back to the camp,” said Dick.  “But we’ll take our fish with us, that’s sure.”

They began to wind up their lines, but knowing that departure would be prudent they were yet reluctant to go in the face of a hidden danger, which after all might not be real.

“Suppose I climb this tree,” said Pennington, indicating a tall elm, “and I may be able to get a good look over the country, while you fellows keep watch.”

“Up you go, Frank,” said Dick.  “George and I will be on guard, pistols in one hand and fish in the other.”

Pennington climbed the elm rapidly and then announced from the highest bough able to support him that he saw open country beyond, then more woods, a glimpse of the stream above the elbow, but no human being.  He added that he would remain a few minutes in the tree and continue his survey of the country.

Dick’s eyes had followed Frank’s figure until it disappeared among the brown leaves, and he had listened to him carefully, while he was telling the result of his outlook, but his attention now turned back to the river.  No more chips were floating down its stream.  Nothing foreign appeared upon the clear surface of its waters, but Dick’s sharp vision caught sight of something in a thicket on the far shore that made his heart beat.

It was but little he saw, merely the brown edge of an enormous flap-brimmed hat, but it was enough.  Slade and his men undoubtedly were there—­ practically within the Union lines—­and he was the danger!  He called up the tree in a fierce sibilant whisper that carried amazingly far: 

“Come down, Frank!  Come down at once, for your life!”

It was a call so alarming and insistent that Pennington almost dropped from the tree.  He was upon the ground, breathless, in a half minute, his fish in one hand and the pistol that he had snatched from his belt in the other.