Nevertheless, he followed them to the dock and watched without comment while they stowed the lad as comfortably as they could on the floor of the little tender, using the cushions off the seats so that he might rest the more easily.

“We’ll let you hear from us in the morning,” cried Ralph, as they shoved off, the man still remaining in silence on the dock.

“Don’t you dare to come back here again,” he bawled in reply. “If you do, I shan’t be alone.”

“Perhaps we shan’t be, either,” shot back Ralph, as he fell to work on the oars.

With this parting dart, they left the strange man of Windmill Island silhouetted against the glowing remains of his hut. As long as they could see him, he stood motionless there, watching the receding boat.

“Well, if this isn’t a night of adventures and mysteries, jumbled up like a tangled fishing line, I’d like to know,” exclaimed Percy Simmons feelingly, as the boat moved slowly through the water.

CHAPTER XIII.
A RACE FOR THE DOCTOR.

“We’ll switch to the motor, Persimmons.”

The dawn comes up early so far north as the St. Lawrence. It was not yet three o’clock in the morning, yet there was a faint gray light illumining the river.

They had been waiting for this. In the darkness, and with the many whirlpools and rapids that occur in that part of the river, it would have been dangerous to do anything more than wait about for daylight. As the light grew stronger the little motor began to crackle and bang, and the tender moved swiftly off through the water in the direction of Dr. Chadwick’s island.