impressions of the
realm of cloud-land, or who had only described their own sensations at
lofty altitudes, had already contributed facts of value to science. It
is time then, taking events in their due sequence, that mention should
be made of the endeavours of various savants, who began about the
commencement of the nineteenth century to gather fresh knowledge from
the exploration of the air by balloon ascents organised with fitting
equipment. The time had now come for promoting the balloon to higher
purposes than those of mere exhibition or amusement. In point of fact,
it had already in one way been turned to serious practical account.
It had been used by the French during military operations in the
revolutionary war as a mode of reconnoitring, and not without success,
so that when after due trial the war balloon was judged of value a
number of similar balloons were constructed for the use of the various
divisions of the French army, and, as will be told in its proper place,
one, at least, of these was put to a positive test before the battle of
Fleurus.

But, returning to more strictly scientific ascents, which began to be
mooted at this period, we are at once impressed with the widespread
influence which the balloon was exercising on thinking minds. We note
this from the fact that what must be claimed to be the first genuine
ascent for scientific observation was made in altogether fresh ground,
and at so distant a spot as St. Petersburg.

It was now the year 1804, and the Russian Academy had determined on
attempting an examination of the physical condition of the higher
atmosphere by means of the balloon. The idea had probably been suggested
by scientific observations which had already been made on mountain
heights by such explorers as De Luc, Saussure, Humboldt, and others. And
now it was determined that their results should be tested alongside such
observations as could be gathered in the free heaven far removed from
any disturbing effects that might be caused by contiguity to earth. The
lines of enquiry to which special attention was required were such as
would be naturally suggested by the scientific knowledge of the hour,
though they may read somewhat quaintly to-day. Would there be any change
in the intensity of the magnetic force? Any change in the inclination
of the magnetised needle? Would evaporation find a new law? Would solar
rays increase in power? What amount of electric matter would be found?
What ch