beyond all, he failed to see what the master genius of Bacon
saw clearly--that his thin globes when exhausted must
infallibly collapse by virtue of that very pressure of the air
which he sought to make use of.

It cannot be too strongly insisted on that if the too much
belauded speculations of Lana have any value at all it is that
they throw into stronger contrast the wonderful insight of the
philosopher who so long preceded him. By sheer genius Bacon had
foreseen that the emptied globe must be filled with SOMETHING,
and for this something he suggests "ethereal air" or "liquid
fire," neither of which, we contend, were empty terms. With
Bacon's knowledge of experimental chemistry it is a question,
and a most interesting one, whether he had not in his mind those
two actual principles respectively of gas and air rarefied by
heat on which we launch our balloons into space to-day.

Early progress in any art or science is commonly intermittent.
It was so in the story of aeronautics. Advance was like that
of the incoming tide, throwing an occasional wave far in front
of its rising flood. It was a phenomenal wave that bore Roger
Bacon and left his mark on the sand where none other approached
for centuries. In those centuries men were either too
priest-ridden to lend an ear to Science, or, like children,
followed only the Will-o'-the-Wisp floating above the quagmire
which held them fast. They ran after the stone that was to
turn all to gold, or the elixir that should conquer death, or
the signs in the heavens that should foretell their destinies;
and the taint of this may be traced even when the dark period
that followed was clearing away. Four hundred years after