The shock was not repeated, and the conversation went on, still as
sharp and as clear as when they had started out. A few minutes later
Jack was able to report they were passing over Rayburn.

"You'd better keep on," said his father, his voice aglow with
enthusiasm. "It's working beyond my wildest expectations."

"It's dandy," agreed Jack.

They talked without raising their voices to any great extent, but it
was necessary to articulate very clearly so that each variation of
sound might be sent out into space as clearly as the notes of a singer
come from the record of a phonograph. But it was amazing, almost
uncanny to Jack that such results could be obtained at all.

"Goodness, if only we could get that mineral substance that dad was
talking about I believe you could rig up a radio telephone that would
talk across the ocean," he said to Tom, "and think what that would
mean. For instance, instead of bothering with the cable you could step
into a radio-telephone office and say: 'Give me the London Exchange.'
In a few minutes the central would answer and you could tell her what
number you wanted on some regular wire line. Before long you'd get it,
and be talking to whoever you had called just as if they were
twenty-five miles off instead of three thousand!"

"It seems like a dream," said Tom.

"Not much of a dream about it. All it needs is development. We've
proved to-day it can be done," declared Jack, bubbling over with
enthusiasm.