answered its helm readily, showed no signs of rolling,
and, in short, appeared to give entire satisfaction to everybody
concerned--so much so, indeed, that Mr. Stanley Spencer informed the
crowd after the ascent that he was quite ready to take up any challenge
that M. Santos Dumont might throw down." Within a few weeks of this his
first success Mr. Spencer was able to prove to the world that he had
only claimed for his machine what its powers fully justified. On a still
September afternoon, ascending alone, he steered his aerial ship in an
easy and graceful flight over London, from the Crystal Palace to Harrow.

CHAPTER XXIX. CONCLUSION.

The future development of aerostation is necessarily difficult to
forecast. Having reviewed its history from its inception we have to
allow that the balloon in itself, as an instrument of aerial locomotion,
remains practically only where it was 120 years ago. Nor, in the nature
of the case, is this to be wondered at. The wind, which alone guides the
balloon, is beyond man's control, while, as a source of lifting power, a
lighter and therefore more suitable gas than hydrogen is not to be found
in nature.

It is, however, conceivable that a superior mode of inflation may yet
be discovered. Now that the liquefaction of gases has become an
accomplished fact, it seems almost theoretically possible that a
balloonist may presently be able to provide himself with an unlimited
reserve of potential energy so as to be fitted for travel of indefinite
duration. Endowed with increased powers of this nature, the aeronaut
could utilise a balloon for voyages of discovery over regions of the
earth which bar man's progress by any other mode of travel. A future
Andree, provided with a means of maintaining his gas supply for six
weeks, need have no hesitation in laying his course towards the North
Pole, being confident that the winds must ultimately waft him to some
safe haven. He could, indeed, well afford, having reached the Pole, to
descend and build his cairn, or even to stop a week, if he so desired,
before continuing on his way.

But it may fairly be claimed for the balloon, even as it now is, that
a great and important future is open to it as a means for exploring
inaccessible country. It may, indeed, be urged that Andree's task
was, in the very nature of the case, well nigh impracticable, and his
unfortunate miscarriage will be used as argument against such a method
of exploration. But it