ngines which
drove it, they must be of a power far beyond the fastest known. By
what force they worked, was equally a problem. Since the boat had no
sails, it was not driven by the wind; and since it had no
smoke-stack, it was not driven by steam.

At this point in the report, I again paused in my reading and
considered the comment I wished to make.

"What are you puzzling over, Strock?" demanded my chief.

"It is this, Mr. Ward; the motive power of this so-called boat must
be as tremendous and as unknown as that of the remarkable automobile
which has so amazed us all."

"So that is your idea, is it, Strock?"

"Yes, Mr. Ward."

There was but one conclusion to be drawn. If the mysterious chauffeur
had disappeared, if he had perished with his machine in Lake
Michigan, it was equally important now to win the secret of this no
less mysterious navigator. And it must be won before he in his turn
plunged into the abyss of the ocean. Was it not the interest of the
inventor to disclose his invention? Would not the American government
or any other give him any price he chose to ask?

Yet unfortunately, since the inventor of the terrestrial apparition
had persisted in preserving his incognito, was it not to be feared
that the inventor of the marine apparition would equally preserve
his? Even if the first machine still existed, it was no longer heard
from; and would not the second, in the same way, after having
disclosed its powers, disappear in its turn, without a single trace?

What gave weight to this probability was that since the arrival of
this report at Washington twenty-four hours before, the presence of
the extraordinary boat hadn't been announced from anywhere along the
shore. Neither had it been seen on any other coast. Though, of
course, the assertion that it would not reappear at all would have
been hazardous, to say the least.

I noted another interesting and possibly important point. It was a
singular coincidence which indeed Mr. Ward suggested to me, at the
same moment that I was considering it. This was that only after the
disappearance of the wonderful automobile had the no less wonderful
boat come into view. Moreover, their engines both possessed a most
dangerous power of locomotion. If both should go rushing at the same
time over the face of the world, the same danger would threaten
mankind everywhere, in boats, in vehicles, and on foot. Therefore it
was absolutely necessary that the police should in