is also known that rotundity of form is not essential to the successful
rising of a balloon. "Well, then," says this philosopher, "what is to
prevent a man making two balloons, flattish, and in the form of wings,
which, instead of flying away with him, as ordinary balloons would
infallibly do, should be so proportioned to his size and weight as that
they would not do more than raise him an inch or so off the ground, and
so keep him stotting and bobbing lightly about, something like the
bright thin india-rubber balls with which children are wont to play
now-a-days?

"Having attained this position of, so to speak, readiness to fly, there
is nothing to prevent him from propelling himself gently along the
surface of the ground by means of fans, or, if you choose, small
flexible cloth wings attached to the hands and arms. The legs might
also be brought into play a little. It is obvious, however, that such
wings would require to be mounted only in calm weather, for a breeze of
wind would infallibly sweep the flyer off the face of the earth! We
would only observe, in conclusion, that, however ridiculous this method
of flying may appear in your eyes, this at least may be said in its
favour, that whereas all other plans that have been tried have signally
failed, _this_ plan has never failed--never having been tried! We throw
the idea before a discriminating public, in the hope that some aspiring
enthusiast, with plenty of means and nerve, and no family to mourn his
loss, may one day prove, to the confusion of the incredulous, that our
plan is not a mere flight of imagination!"

When men began to find that wings refused in any circumstances to waft
them to the realms of ether, they set about inventing aerial machines in
which to ascend through the clouds and navigate the skies.

In the fourteenth century a glimmering of the true principles on which a
balloon could be constructed was entertained by Albert of Saxony, a monk
of the order of Saint Augustin, but he never carried his theories into
practice. His opinion was that, since fire is more attenuated than air,
and floats above the region of our atmosphere, all that was necessary
would be to enclose a portion of such ethereal substance in a light
hollow globe which would thus be raised to a certain height, and kept
suspended in the sky, and that by introducing a portion of air into the
globe it would be rendered heavier than before, and might thus be made
to descend. Th