of the
wireless telegraph are sped through the ether, quickened their
inventive faculties to the highest pitch. Both felt a glow of pride
that they had been selected, even before their father's scientific
friends, to make the first test of this wonderful new invention.

They hurried across the broad lawn that intervened between the
workshops and the orchard where the newly erected shed stood, and
which, it had been given out, was to serve for the storage of
gasoline. Unlocking the door, they found inside an apparatus
resembling in almost every detail the one in Mr. Chadwick's workshop.

Jack's hands fairly trembled as he started up the motor and the
generator began to buzz. With shining eyes and throbbing pulses he
placed the receiver to his ear as his father had directed. But the
next moment a flood of disappointment swept through him.

"Well?" demanded Tom, himself a tiptoe with expectation.

"Nothing doing," replied Jack, shaking his head. "I guess the thing
isn't at a practical stage yet."

"Wait a minute, give it a chance," urged Tom. "By the way, how about
that tuning device, have you tried that yet?"

"No, good gracious, my head must be turning into solid ivory from the
neck up. I guess that's just what the trouble is."

Jack began carefully sliding a small block connected to the
instruments up and down the coiled wire which formed the tuning
apparatus, and brought the sending and receiving ends into harmony
just as if they had been two musical instruments. When the right
electric "chord" was struck he should be able to hear, just as in
wireless he would be able to catch the message of an instrument whose
wave lengths were attuned to his.

Suddenly Tom saw his chum and cousin give a start and then a shout.
Over the space between the workshop and the small shed a human voice
had been borne on electric waves. Sharp and clear as though he had
been listening to a "wire" 'phone, Jack caught and recognized his
father's voice:

"Hul-lo!"

CHAPTER VI.

THE RADIO TELEPHONE.

Back and forth through space they talked for quite a time. The boys
were jubilant. The despair of many inventors, the wireless or radio
telephone appeared to be an accomplished fact. But they didn't dream
how much yet remained to be done. At length Mr. Chadwick told them to
"hang-up" and come back to the workshop.

The boys were glad to do this for they were extremely anxious to learn
something of the forces controlling this