“Yes, but you do seem to turn up at most opportune times.  Luck is certainly with you where she is concerned.  First you save her in a runaway—­”

“After I start the runaway,” interrupted Tom.

“Then you take her for a ride in your motor-boat, and, lastly, you come to her relief when she is stalled in the middle of the lake.  Oh you certainly are a lucky dog!”

“Never mind, I’m giving you a show.  Now let’s get to bed early, as I want to get a good start.”

Tom awoke to find a nasty, drizzling rainstorm in progress, and the lake was almost hidden from view by a swirling fog.  Still he was not to be daunted from his trip to Shopton by the weather, and, after a substantial breakfast, he bade his father and Ned good-by and started off in the arrow.

The canopy he had provided was an efficient protection against the rain, a celluloid window in the forward hanging curtains affording him a view so that he could steer.

Through the mist puffed the boat, the motor being throttled down to medium speed, for Tom was not as familiar with the lake as he would like to have been, and he did not want to run aground or into another craft.

He was thinking over what his father had told him about the presence of the men and vainly wondering what might be their reference to the “sparkler.”  His thoughts also dwelt on the curious removal of the bracing block from under the gasoline tank of his boat.

“I shouldn’t be surprised but what Andy Foger did that,” he mused.  “Some day he and I will have a grand fight, and then maybe he’ll let me alone.  Well, I’ve got other things to think about now.  The hotel detective can keep a lookout for the men around the hotel, after the, warning I gave him, and I’ll see that all is right at home.”

The fog lifted somewhat and Tom put on more speed.  As he was steering the boat along near shore he heard, off to the woods at his right, the report of a gun.  It came so suddenly that he jumped involuntarily.  A moment later there sounded, plainly through the damp air, a cry for help.

“Some one’s hurt—­shot” cried the youth aloud.

He turned the boat in toward the bank.  As he shut off the power from the motor he heard the cry again: 

“Help!  Help!  Help!”

“I must go ashore!” he exclaimed.  “Probably some one is badly wounded by a gun.”

He paused for a moment as the fear came to him that it might be some of the patent thieves.  Then, dismissing that idea as the ARROW’s prow touched the gravel, Tom sprang out, drew the boat up a little way, fastened the rope to a tree and hurried off into the dripping woods in the direction of the voice that was calling for aid.

CHAPTER XI

A QUICK RUN

“Where are you?” cried Tom.  “Are you hurt?  Where are you?”

Uttering these words after he had hurried into the woods a short distance, the young inventor paused for an answer.  At first he could hear nothing but the drip of water from the branches of the trees; then, as he listened intently, he became aware of a groan not far away.