Harry Girdwood saw it all, and his terror increased every moment.

Well it might.

The mad struggles of the stranger imperilled both.

"Dive, Jack, dive," cried Harry Girdwood, frantically; "dive with him,
or it is all up with both of you."

Jack heard him.

Twisting like an eel in the embrace of the boy he would save, he dived
down, dragging the stranger with him.

In the space of a few seconds he reappeared again upon the surface,
observing his former tactics.

Striking out with his right arm, while with his left hand he grasped
the stranger's long black hair.

"Catch hold of him," gasped young Jack; "never mind me."

Harry Girdwood leant over the boat's side and caught at the stranger by
the collar.

"There; hold on like that," said young Jack.

The weight coming all upon one side of the boat, however, threatened to
capsize it, and so they had to act with the greatest precaution.