From the very centre of the clump of wood rose a thin, shadowy line of vapor, which was dissolved in the clear air before it ascended more than a few feet above the tree-tops.
"So you obsarve it at last," said the hunter, after they had told what they saw.

"Wal, now study it closer, and tell me if you notice anything queer 'bout the same." Wondering what he could mean, they did as he requested.

A minute later Fred said: "The smoke does not ascend steadily; first it shows plainly, then there is none, and then it shows again." "Seems to keep it up, eh ?" "Yes, like the puffs from the smoke-stack of a locomotive, only they are a great deal slower," explained Jack; "but the smoke soon dissolves in the clear air." "Not soon enough, though, to keep you from obsarving what we've been talking about ?" "No; it is too plain to be mistaken." "Did you ever see the smoke of a camp-fire act like that ?" "Never; have you ?" "Many a time; that's an Injin signal-fire." This was interesting, but caused nothing in the nature of fear on the part of the boys.

It was Fred who remarked: "The Indians must be signaling to some one." "Exactly." "It can't be to _us_ ?" "Not much; it's to another party of Injins, and that other party is calling back to 'em.

See whether you can find t'other signal." The boys moved the points of their glasses back and forth and up and down, but it was not until their guide again pointed out the right spot that they located the second signal.