down the hatch, an' swush-swuey, down she went, an' all dey left was a
splash in de ol' Chicago!"

"A submarine!" Johnny exclaimed. "That doesn't sound possible; not a
German submarine surely!"

"The same," insisted Jerry. "Some old tub. Saw her over by the Municipal
Pier, er one like her. Some old fish!"

Johnny sat in silent thought. Hanada was gazing out of the window.
Suddenly the Jap exclaimed in surprise:

"Did you see that? There it goes again! Lights flashing beneath the
water. It's the 'sub' for sure. Couldn't be anything else."

"I have seen such lights before," said Johnny, striving hard to maintain
a sane judgment in this time of great crisis, "but I attributed it to
phosphorus on the water."

"Couldn't be!" declared Hanada. "Couldn't make a flicker and flash like
that. I tell you, it's a submarine, and the home of the Radicals. That's
why we couldn't find them. That's where our Russian disappeared to that
night on the bridge. That's where the shots came from. Remember right
from the center of the river? That's where your four assailants went to
when they vanished from that deserted building. It's the Radicals.
C'mon! We may not be too late yet. We'll get them before the police get
us."

Together the three rushed from the room.