ns to be seen. It does not seem probable, but no one
can say authoritatively that it is impossible. It is demonstrable,
however, that to rise, or even to remain suspended, in the air by means
of machinery impelled by human force alone is a feat which is as much an
impossibility as it is for a man, by the strength of his own legs, to
leap thirty or forty times his own length,--a grasshopper can do that
easily, and a bird can fly easily, but a man cannot, and never will be
able to do so, because his peculiar conformation forbids it.

This was first demonstrated by Borelli, an eminent Italian mathematician
and philosopher, who lived in a fertile age of discovery, and was
thoroughly acquainted with the true principles of mechanics and
pneumatics. He showed, by accurate calculation, the prodigious force,
which in birds must be exerted and maintained by the pectoral muscles,
with which the all-wise Creator has supplied them, and, by applying the
same principles to the structure of the human frame, he proved how
extremely disproportionate was the strength of the corresponding muscles
in man. In fact, the man who should attempt to fly like a bird would be
guilty of greater folly and ignorant presumption than the little infant
who should endeavour to perform the feats of a gladiator! It is well
for man in all things to attain, if possible, to a knowledge of what
certainly lies beyond his powers, for such knowledge prevents the waste
and misdirection of energies, as well as saving from disappointment and
other evil results.

But many of those enthusiasts, who have attempted at various periods of
the world's history to fly, did not fall into the error which we have
attempted to point out. On the contrary, they went intelligently to
work; their only aim being modestly to fly _somewhat_ after the manner
of a bird, but they all failed; nevertheless one philosopher, of modern
times, stoutly continued to assert the opinion that there is no
impossibility in man being able to fly _apparently_, though not really,
like a bird. He did not hold that man could ever fly as high, or as
far, or as fast, or in any degree as easily, as a bird. All that he
ventured to say was, that he might perhaps fly _somewhat like one_.

As the plan of this philosopher is rather curious, we shall detail it.

It is well known that balloons, filled with appropriate gas, will rise.
Big balloons and little ones are equally uppish in their tendencies. It