ow mankind how to navigate the air. His
ideas are perfectly easy to grasp. He conceived that the air was a true
fluid, and as such must have an upper limit, and it would be on this
upper surface, he supposed, as on the bosom of the ocean, that man would
sail his air-ship. A fine, bold guess truly. He would watch the cirrus
clouds sailing grandly ten miles above him on some stream that never
approached nearer. Up there, in his imagination, would be tossing the
waves of our ocean of air. Wait for some little better cylinders of
oxygen and an improved foot-warmer, and a future Coxwell will go aloft
and see; but as to an upper sea, it is truly there, and we may visit and
view its sun-lit tossing billows stretching out to a limitless horizon
at such times as the nether world is shrouded in densest gloom. Bacon's
method of reaching such an upper sea as he postulated was, as we have
said, by a hollow globe.

"The machine must be a large hollow globe, of copper or other suitable
metal, wrought extremely thin so as to have it as light as possible,"
and "it must be filled with ethereal air or liquid fire." This was
written in the thirteenth century, and it is scarcely edifying to find
four hundred years after this the Jesuit Father Lana, who contrived to
make his name live in history as a theoriser in aeronautics, arrogating
to himself the bold conception of the English Friar, with certain
unfortunate differences, however, which in fairness we must here clearly
point out. Lana proclaimed his speculations standing on a giant's
shoulders. Torricelli, with his closed bent tube, had just shown
the world how heavily the air lies above us. It then required little
mathematical skill to calculate what would be the lifting power of
any vessel void of air on the earth's surface. Thus Lana proposed
the construction of an air ship which possibly because of its
picturesquesness has won him notoriety. But it was a fraud. We have
but to conceive a dainty boat in which the aeronaut would sit at ease
handling a little rudder and a simple sail. These, though a schoolboy
would have known better, he thought would guide his vessel when in the
air.

So much has been claimed for Father Lana and his mathematical and other
attainments that it seems only right to insist on the weakness of his
reasoning. An air ship simply drifting with the wind is incapable of
altering its course in the slightest degree by either sail or rudder. It
is simply like a log