thy or
surprising than the following experience Of the writer on Whit Monday of
1899. The ascent was under an overcast sky, from the Crystal Palace at
3 p.m., at which hour a cold drizzle was settling in with a moderate
breeze from the east. Thus, starting from the usual filling ground near
the north tower, the balloon sailed over the body of the Palace, and
thence over the suburbs towards the west till lost in the mist. We then
ascended through 1,500 feet of dense, wetting cloud, and, emerging in
bright sunshine, continued to drift for two hours at an average altitude
of some 3,000 feet; 1,000 feet below us was the ill-defined, ever
changing upper surface of the dense cloud floor, and it was no longer
possible to determine our course, which we therefore assumed to have
remained unchanged. At length, however, as a measure of prudence, we
determined to descend through the clouds sufficiently to learn something
of our whereabouts, which we reasonably expected to be somewhere in
Surrey or Berks. On emerging, however, below the cloud, the first object
that loomed out of the mist immediately below us was a cargo vessel,
in the rigging of which our trail rope was entangling itself. Only
by degrees the fact dawned upon us that we were in the estuary of the
Thames, and beating up towards London once again with an cast wind. Thus
it became evident that at the higher level, unknown to ourselves, we had
been headed back on our course, for two hours, by a wind diametrically
opposed to that blowing on the ground.

Two recent developments of the hot-air war balloon suggest great
possibilities in the near future. One takes the form of a small captive,
carrying aloft a photographic camera directed and operated electrically
from the ground. The other is a self-contained passenger balloon of
large dimensions, carrying in complete safety a special petroleum burner
of great power. These new and important departures are mainly due to the
mechanical genius of Mr. J. N. Maskelyne, who has patented and perfected
them in conjunction with the writer.

CHAPTER XXVIII. THE CONSTITUTION OF THE AIR.

Some fair idea of the conditions prevailing in the upper air may have
been gathered from the many and various observations already recorded.
Stating the case broadly, we may assert that the same atmospheric
changes with which we are familiar at the level of the earth are to
be found also at all accessible heights, equally extensive and equally