Certainly in that case its engine must be one of amazing power.
Perhaps the inventor before selling the secret of his invention,
sought to attract public attention and to astound the maritime world.
Such surety in the movements of his boat, grace in its every
evolution, such ease in defying pursuit by its arrow-like speed,
surely, these were enough to arouse world-wide curiosity!

At that time great progress had been made in the manufacture of
marine engines. Huge transatlantic steamers completed the ocean
passage in five days. And the engineers had not yet spoken their last
word. Neither were the navies of the world behind. The cruisers, the
torpedo boats, the torpedo-destroyers, could match the swiftest
steamers of the Atlantic and Pacific, or of the Indian trade.

If, however, this were a boat of some new design, there had as yet
been no opportunity to observe its form. As to the engines 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."