ame so interested that they could hardly believe it was lunch time,
when the whistles blew and the men threw down their tools and prepared to
take a well earned rest for a brief hour. "Well," said Bert, glancing at
his watch, "I guess it's about time we hit the trail toward the nearest
eats emporium. Now that its called to my attention, I begin to realize
that I'm hungry."

The others also discovered symptoms of a healthy appetite, so without
further loss of time they hurried back to their 'base of supplies' as Tom
put it.

"If we're as hungry as this without having done much all the morning,
what would we be if we had been working since eight o'clock?" queried
Dick, and the others were unable to give him a satisfactory answer.

"I guess they'd have to stop work, owing to a shortage in the food
supply," said Bert, and his companions laughingly agreed with him.

They made a hearty lunch, and then returned to the scene of the
excavations. There were a thousand interesting things to watch, and the
afternoon passed very quickly. Their attention was specially attracted
by one giant steam shovel that rattled and puffed like some untiring
monster. The engineer guiding it directed its every motion with a touch
of one of the levers close to his hand, and it seemed as though the
machine were a living creature and he its brain. The great scoop would
drop with a roar of chains passing through pulleys, and then, as the main
engine began to puff, would rise slowly but with irresistible force..
Then a pair of auxiliary cylinders mounted on the beam of the shovel
would begin to work, and the big scoop with its load of dirt and rocks
would swing around and stop over one of the dirt cars. The engineer's
assistant would pull a rope attached to the scoop, a catch would be
released, and the bottom of the scoop would swing open, letting the load
fall into the waiting car. This process would be repeated again and
again, and then, when the shovel had scooped up all the dirt around it,
it would be moved forward a few feet, under its own power, to a new base
of operations.

It seemed that its power was almost limitless, but at last there came a
time when the boys thought it would meet an insurmountable obstacle.
Close to where they sat, a big stump projected from the ground. Part of
its gnarled and twisted roots was exposed, but a good deal of it was
firmly imbedded in the earth. The steam shovel had worked its way along,
until no