ng," replied the doctor. "Likely enough it will
take the place of the great transatlantic plants which require so much
room and such enormous machinery. It's practically noiseless. Direct
current is sent into the wire through a complicated wire system and
generates a high frequency current of tremendous power. I saw it working
when it was connected with an apparatus carrying about fifteen thousand
volts of electricity in a direct current. A small blue flame shot
through the tube with scarcely a particle of noise. The broken impulse
from the electrical generators behind the tube was sent through the tube
to be flung off from the antenna into space in the dots and dashes of
the international code. That little tube was not much bigger than a
stick of dynamite, but was infinitely more powerful. I was so fascinated
by it and all that it meant that it was hard work to tear myself away
from it. It marks a great step forward in the field of radio."

"It must have been wonderfully interesting," remarked Bob. "And yet I
suppose that in a year or two something new will be invented that will
put even that out of date."

"It's practically certain that there will be," assented the doctor. "The
miracles of to-day become the commonplaces of to-morrow. That
fifty-kilowatt tube that develops twelve horsepower within its narrow
walls of glass, wonderful as it is, is bound to be superseded by
something better, and the inventor himself would be the first one to
admit it. Some of the finest scientific brains in the country are
working on the problem, and he would be a bold prophet and probably a
false prophet that would set any bounds to its possibilities.

"Radio is yet in its infancy," the doctor concluded, as he rose to go.
"But one thing is certain. In the lifetime of those who witnessed its
birth it will become a giant--but a benevolent giant who, instead of
destroying will re-create our civilization."

CHAPTER VI

THE FOREST RANGER

Some days later Bob and Herb and Joe were on their way to Bob's house to
do a little experimenting on the latter's set, when they were surprised
at the alacrity with which Jimmy turned a corner and came puffing up to
them.

"Say, fellows!" he yelled, as he came within earshot, "I've got some
mighty interesting news for you."

"Let's have it," said Bob.

"It's about the snowball Buck fired through the window," panted Jimmy,
falling into step beside them. "I met a man who's staying up at th