rd Porton once more, when Dave was within
ten yards of him. And then he turned squarely around and our hero and
Roger saw the glint of a pistol as the rascal pointed it toward them.

"He is armed!" cried Roger, and now there was a note of fear in his
voice, and not without reason.

"Get behind the steel work," ordered Dave, and lost no time in dodging
partly out of sight. As he moved, however, he launched forth the steel
bar he had picked up.

More by good luck than anything else the bar sped true to its mark. It
struck Ward Porton in the forearm, the hand of which was holding the
pistol. In another instant the weapon was clattering down through the
steel work of the bridge to the river far below.

"Hurrah, Dave! you've disarmed him!" cried Roger.

For the instant Ward Porton seemed dazed by the sudden turn of
affairs. Evidently, however, the blow from the steel bar had not hurt
him much, for, turning quickly, he continued his flight along the
bridge. Dave and Roger lost no time in following him.

It was not long before the fugitive and those behind him reached a
section of the long bridge which was far from completed. Here there
was practically no flooring, and Ward Porton had to jump from one
piece of steel work to another, while Dave and Roger, of course, had
to do the same. Once those in the rear saw the rascal ahead make a
misstep and plunge downward. But he saved himself, and, scrambling to
his feet, dashed forward as madly as before.

"Take care, Dave, it's dangerous here," gasped Roger; and scarcely had
he spoken when he himself made a misstep and shot down below the level
of the bridge flooring.

Dave was several feet in advance, but turned instantly when his chum
let out a cry of alarm. He saw Roger four or five feet below him,
clinging frantically to one of the stays of the bridge.

"Hel--help m--me!" panted the unfortunate youth.

"Hold tight, Roger. I'll help you," returned Dave, quickly.

[Illustration: "HOLD TIGHT, ROGER! I'LL HELP YOU," RETURNED DAVE,
QUICKLY.--_Page 255._]

The stay below was so small in diameter that all Roger could do was to
cling to it with both hands and one leg. In this position he hung
until Dave let himself down several feet and managed to give him a
hand. Then with extreme caution both worked their way back to the
unfinished flooring of the bridge.

"Oh my! I thought sure I was a goner!" panted the senator's son, when
he found himself safe once more. He had turne