But there was another danger, however, and this was that he might run into another boat.  True, there were not many on Lake Carlopa, but there were some, and one of the few motor-boats might be out in spite of the bad weather.

“Guess I’ll not run at full speed,” decided Tom.  “I wouldn’t like to crash into the red streak.  We’d both sink.”

So he did not run his motor at the limit and sat at the steering-wheel, peering ahead into the fog for the first sight of another craft.

He turned to look at Mr. Duncan and was alarmed at the pallor of his face.  The man’s eyes were closed and he was breathing in a peculiar manner.

“Mr. Duncan,” cried Tom, “are you worse?”

There was no answer.  Leaving the helm for a moment, Tom bent over the injured hunter.  A glance showed him what had happened.  The tourniquet had slipped and the wound was bleeding again.  Tom quickly shut off the motor, so that he might give his whole attention to the work of tightening the handkerchief.  But something seemed to be wrong.  No matter how tightly he twisted the stick the blood did not stop flowing.  The lad was frightened.  In a short time the man would bleed to death.

“I’ve got to get him to the sanitarium in record time!” exclaimed Tom.  “Fog or no fog, I’ve got to run at full speed!  I’ve got to chance it!”

Making the bandage as tight as he could and fastening it in place, the young inventor sprang to the motor and set it in motion.  Then he went to the wheel.  In a few minutes the arrow was speeding through the water as it had never done before, except when it had raced the red streak.  “If I hit anything—­good-by!” thought Tom grimly.  His hands were tense on the rim of the steering-wheel and he was ready in an instant to reverse the motor as he sat there straining his eyes to see through the curtain of mist that hung over the lake.  Now and then he glanced at the compass, to keep on the right course, and from time to time he looked at Mr. Duncan.  The hunter was still unconscious.

How Tom accomplished that trip he hardly remembered afterward.  Through the fog he shot, expecting any moment to crash into some other boat.  He did pass a rowing craft in which sat a lone fisherman.  The lad was upon him in an instant, but a turn of the wheel sent the arrow safely past, and the startled fisherman, whose frail craft was set to rocking violently by the swell from the motor-boat, sent an objecting cry through the fog after Tom.  But the youth did not reply.  On and on he raced, getting the last atom of power from his motor.

He feared Mr. Duncan would be dead when he arrived, but when he saw the dock of the sanitarium looming up out of the mist and shut off the power to slowly run up to it, he placed his hand on the wounded man’s heart and found it still beating.

“He’s alive, anyhow,” thought the youth, and then his craft bumped up against the bulkhead and a man in the boathouse on the dock was sent on the run for a physician.