therefore, suppose that I have an air propellor inside, and that air is
necessary to react against it, like water against the screw of a
steamboat, in order to produce the motion. I will now show you that air
is not required, and that my locomotive works quite as well in a
vacuum."

So saying, he put the model under a large bell-jar, from which he
exhausted the air with a pump; and even then it moved about with as much
alacrity and freedom as it had done in the atmosphere.

I confess that I was still haunted by a lingering suspicion of the
machine and its inventor; but this experiment went far to destroy it.
Even if the motive power was derived from a coiled spring, or compressed
air, or electricity, in the box, how was it possible to make it act
without the resistance offered by the air? Magnetism was equally out of
the question, since no conceivable arrangement of magnets could have
brought about the movements I had seen. Either I was hypnotised, and
imposed upon, or else this man had discovered what had been unknown to
science. His earnest and straightforward manner was not that of a
mountebank. There had been no attempt to surround his work with mystery,
and cloak his demonstration in unmeaning verbiage. It is true I had
never heard of him in the world of science, but after all an outsider
often makes a great discovery under the nose of the professors.

"Am I to understand," said I, "that you have found a way of navigating
both the atmosphere and the ether?"

"As you see," he replied, briefly.

"What the model has done, you are able to do on a larger scale--in a