er of an hour elapsed. By that time they could see across fairly
well.

"First of all," Rob summed up, "there doesn't seem to be anybody over
there to bother us, that I can notice."

"And the way across isn't so bad, that I can see," announced Merritt,
principally to help buoy up the sinking heart of poor Tubby. "Why, all
of us have done stunts worse than that. You know we have, Tubby, many a
time."

"Well," Tubby answered him weakly, "just as you say, boys. I'm in your
hands. I promise to do the best I can to get over; but, if I _should_
slip, please get me out of the river as soon as you can. You know I'm
not a cracking good hand at swimming."

Of course they promised, and cheered him up by every means possible; but
it was with many doubts that in the end Tubby consented to start forth
on the trip.

Rob led the way, and after him came the fat chum, with Merritt bringing
up the rear. There was a method in this arrangement, for, while the
pilot could test each girder, so as to pronounce it secure, the rear
guard was able to keep an eye on luckless Tubby, and even give him an
occasional word of advice.

Now that the morning had arrived they could see better with each passing
minute; and Rob soon declared there was no necessity for any further
delay.

It was always a principle with him to grapple with a difficulty, and
carry out his plans, without letting anything like dismay seize hold of
his heart.

Accordingly Rob now made a start.

"Why, this is dead easy," was the way he sung out, after he had passed
along the swaying girder for a little distance. "All you have to make
sure of is that your grip is sound. Then keep hunching along, foot by
foot. And don't look down any more than you can help, because it might
make you dizzy."

Tubby shut his teeth hard, and began to follow after the pilot. He made
good progress until he had about reached the middle of the rocking span.
Then Rob was really alarmed to hear a sudden loud cry, and feel his
slender hold shaken violently.

Something had certainly happened to unfortunate Tubby!

CHAPTER XXII.

SCOUT TACTICS.

Just as he feared, when Rob managed to turn around and look back, he
found that Tubby had gone and done it again. Whether he had missed his
footing, or something had given way under his additional weight, was a
question that could not be decided.

Before Merritt, close in his rear, could thrust out a helping hand, poor
Tubby had fallen. The