"If you do," Jack called after him, "I'll--"

Benson's voice died down as the young captain felt Hal Hastings's strong,
impassioned grip on his arm.

Radwin, fortunately, did not turn, but kept on until he had taken himself
out of sight.

Jack turned an inquiring glance on his chum's face. But Hal's warning
look seemed to say:

"Silence! Wait!"

"What was the row about?" asked a stranger among those who had pressed
about the boys.

"Nothing," returned Eph Somers, shortly, glaring at his questioner.

At a mute signal from Hal all three of the submarine boys seated
themselves once more.

By degrees the little crowd melted away.

Then Jack Benson turned to his chum, to ask, in a low voice:

"What did you mean, Hal, old fellow? I know you had some good reason
for checking me as you did."

"I was afraid you would hit Radwin," Hal murmured.