es painted on the floor of that last room we came
through, the one where all those castings were stacked up in rows," said
Chance. "Was that what they were for? Great scheme, isn't it? And as
simple as falling off a log!"

"Simple? Sure--most of these things are simple enough, once you think of
them," agreed their guide. "It took perhaps an hour of one man's time
and a gallon or two of white paint to paint those dead-lines along the
sides--and many's the man who has been saved weeks in the hospital by
those same white lines."

The five friends followed him into the foundry department. Hardly had
they stepped through the doorway, when the clang of a big gong overhead
scattered a group of laborers who were piling heavy castings on flat
cars.

Five pairs of eyes looked up as the five Safety Scouts turned to see
where the gong was. Away up above them on a track that went from one end
of the long room to the other, they saw something like an oddly shaped
freight engine running along with a heavy wire cable dangling toward the
floor. The big, strong cable was carrying a load of several tons of
steel castings as easily as a boy carries in an armful of wood. "And
with a whole lot less fuss and bother!" said Betty, with a sly look at
Brother Bob.

"When a man hears that gong overhead," said the guide, "he knows what it
means even before he looks up. That's what is called a traveling crane.
It runs back and forth on those overhead tracks, wherever the crane
driver wants to pick up or drop his load. He kicks that gong with his
heel, just like the motorman on the street car, and it gives warning to
the workmen below just as plainly as if it yelled out, 'Look out, below!
Here comes a load that might spill on your heads!'"

"Sounds exactly like a street-car gong," said Betty.

The steel man smiled. "It ought to--it was made for use on a street car.
Watch sharp when the crane comes back this way and you'll see the gong
fastened right up under the cab floor. See? We tried whistles for a
while, and automobile horns, too; but this plain, everyday street-car
gong beats 'em all. A man doesn't have to understand English to know
what _that_ sound means!"

"It must have made a good deal of difference in the number of
accidents," said Sure Pop, "with so many men working underneath those
cranes right along."

"Did it? Well, I should say so! That's another little thing that's as
simple as A B C, but it saves lives and broken bones just