"There isn't any bog or swamp around here, Mr. Damon. If there was I shouldn't have tried a landing. No, it's something else besides that. Hark!"

Again the cry sounded, seeming to come from a point behind the landing place of the silent airship. It was clear and distinct:

"Help! Help! They are—"

The voice seemed to die away in a gurgle, as though the person's mouth had been covered quickly.

"He's sinking, Tom! He's sinking!" cried Mr. Damon. "I once heard a man who almost drowned cry out, and it sounded exactly like that!"

"But there isn't any water around here for any one to drown in," declared Tom. "It's a big, dry meadow. I know where we are."

"Then what is it?"

"I don't know, but we're going to find out. Some one attacked by some one else—or something, I should say," ventured the young inventor.

"Something! do you mean a wild beast, Tom?"

"No, for there aren't any of those here any more than there is water. Though it may be that some farmer's bull or a savage dog has got loose and has attacked some traveler. But, in that case I think we would hear bellows or barks, and all I heard was a cry for help."