difficult to judge. But a glimpse along shore showed him that they were slipping through the water at a faster speed.
"They're up to something!" suddenly exclaimed Mr. Damon a moment later. "I believe they're going to fire on us, Tom. They are pointing something this way."
The lad stood up and gazed earnestly at his boat, which seemed to be slipping away from him so fast. One of the occupants was in the stern, aiming some glittering object at those in the Red Streak. For a moment Tom thought it might be a gun. Then, as the man turned, he saw what it was.
"A pair of marine glasses!" cried the lad. "They're trying to make out who we are."
"I guess they know well enough," rejoined Mr. Damon. "Can't you go any faster, Tom?"
"I'm afraid not. But we'll land them, sooner or later. They can't go very far in this direction without running ashore and we'll have them. They're cutting across the lake now."
'They may escape us if it gets dark. Probably that's what they're working for. They want to keep ahead of us until nightfall."
The young inventor thought of this too, but there was little he could do. The motor was running at top speed. It could be made to go faster,
