ss the charm of an obvious and somewhat quaint
reality. They commence with certain crude calculations which would seem
to place no limit to the capabilities of a balloon. Thus, he points out
that one of "the very moderate size of 400 feet diameter" would convey
13,000 men. "No wonder, then," he continues, "the citizens of London
became alarmed during the French War, when they mistook the appearance
of a vast flock of birds coming towards the Metropolis for Napoleon's
army apparently coming down upon them with this new contrivance."

Proceeding to practical measures, Wise's first care was to procure some
proper material of which to build an experimental balloon of sufficient
size to lift and convey himself alone. For this he chose ordinary
long-cloth, rendered gas-tight by coats of suitable varnish, the
preparation of which became with him, as, indeed, it remains to this
day, a problem of chief importance and difficulty. Perhaps it hardly
needs pointing out that the varnish of a balloon must not only
be sufficiently elastic not to crack or scale off with folding or
unavoidable rough usage, but it must also be of a nature to resist the
common tendency of such substances to become adherent or "tacky." Wise
determined on bird lime thinned with linseed oil and ordinary driers.
With this preparation he coated his material several times both before
and after the making up, and having procured a net, of which he speaks
with pride, and a primitive sort of car, of which he bitterly complains,
he thought himself sufficiently equipped to embark on an actual ascent,
which he found a task of much greater practical difficulty than the mere
manufacture of his air ship. For the inflation by hydrogen of so small
a balloon as his was he made more than ample provision in procuring
no less than fifteen casks of 130 gallons capacity each. He also duly
secured a suitable filling ground at the corner of Ninth and Green
Streets, Philadelphia, but he made a miscalculation as to the time the
inflation would demand, and this led to unforeseen complications, for
as yet he knew not the way of a crowd which comes to witness a balloon
ascent.

Having all things in readiness, and prudently waiting for fair weather,
he embarked on his grand experiment on the 2nd of May, 1835, announcing
4 p.m. as the hour of departure. But by that time the inflation, having
only proceeded for three hours, the balloon was but half full, and then
the populace began to be