“If we can continue to hear the bell for a quarter of an hour I shall be quite satisfied,” he had remarked to Mildmay, as the ship first rose into the air; “for by that time we shall be quite fifty miles distant from the beach.”
And when the quarter of an hour had elapsed with no perceptible diminution in the volume of sound, his growing satisfaction had been faithfully mirrored by the steadily expanding smile upon his expressive features. Finally, when at length the bells ceased to ring, he exclaimed—
“Well! who would have believed it? Here have I, a poor silly scientist, been hoping that my little invention would prove effective for as long a distance as fifty miles; and behold, at the distance of one hundred and twenty miles from our friends we have only just lost touch with them. Let us try back, my friend; turn the ship round, and we will then note how far we have to run before we can speak clearly to each other.”
Mildmay accordingly put the helm hard over, and when the compass showed that the ship was once more pointing directly toward the spot on the beach where the remainder of the party had been left, the professor drew out his watch, and carefully noted the time. Almost immediately the bells again began to tinkle, at first very faintly and intermittently, but rapidly increasing in strength as the ship sped back over the ground that she had traversed a few minutes earlier. By the time that she had run ten miles on her return journey the bells were again ringing quite strongly.
“Stop her!” commanded von Schalckenberg. “We are now one hundred and ten miles from our friends, and I think we ought to be within speaking distance of them. Let us try.”
He touched the red knob of the instrument, and at the same time inserted the end of the tube in his ear. Almost instantly a faint but quite distinct shout came to him:
“Hillo, von Schalckenberg, where are you now?” he heard Sir Reginald’s voice inquire.
“We are just one hundred and ten miles distant from you,” answered the professor. “Can you hear me distinctly?”
“Yes, quite distinctly; although your voice does not sound quite so loud as it did,” came the reply. “It sounds as though you were about a hundred feet away.”
“Still, if you can hear me clearly enough to distinguish what I say, it is good enough. You will hear me more distinctly as we shorten the distance between you and ourselves. By the way, have you met with any luck yet in your search for rubies?”