unless they've wrecked the track."
Then, as the huge iron monster lifted itself to greater speed, Mr. Ellis
saw something like a white flag wave in the air then fall. Once more it
circled, one, two, three, four, five times above someone's head, fell
again, then was tossed from one hand high in the air and caught in the
other.

"Jim, I've seen that signal somewhere. It means something." Then, like a
photograph, he seemed to see a lake, two boys swimming, and a black bear
and cubs on a far shore, while Benny's voice rang in his ears: "Five
circles means 'Great danger,' and a toss from one hand to the other up
through the air means 'Don't move; stay where you are.'"

"It's the boys, Jim," gasped the engineer. "There's something wrong."
Before the words had left his lips the shrill whistle was shrieking for
"brakes"--"double brakes" at that--and the gigantic engine almost leaped
from the rails as the halter was thrown about her neck. On she rushed,
slipping, grinding, rocking in her restraint. The train crew and
passengers in the rear car pitched almost on their faces with the
violent checking of speed, until, snorting and pulsing and belching,
the great mogul came to a standstill.

"Oh, daddy, you _did_ remember, you _did_, after all!" cried a very
white-faced little boy who peered up into the cab window with horrified
eyes, while his naked shoulders heaved, and his hand clutched a torn,
faded blue shirt.

"What's the meaning of this nonsense, Ellis?" thundered an angry voice
behind him, and the superintendent, black with scowling, glared at first
the boy, then the engineer. "What's this stop for, when you know I
haven't a minute to spare getting to Dubuc? You nearly broke my neck,
too, downing brakes. What does it mean, I say?"

But when the boys, bold with excitement, dragged the great man around
the curve, and pointed to the doomed trestle, with its already falling
timbers, it was another story altogether. From the engineer's white lips
he listened to the history of Benny's "signal code." Then for a long
time the great man stood looking at the burning trestle. Once he
muttered aloud, "All our lives, a priceless engine, valuable freight,
rolling stock, _all saved_!" Then, whirling rapidly on his heel, he
said, "Ellis, we want your boy on the road when he's bigger. The boy
who can invent a useful plaything and keep his head in an emergency is
the boy we want to make into a man on the great Transcontinental. Will
you