garded; but the fact remains that in the experience of the writer
and of many others whom he has consulted, there is no such optical
illusion as I have just discussed, and to their vision it is impossible
to regard the earth as anything but uniformly flat.

Another impression invariably insisted on by early balloonists is that
the earth, on quitting it, appears to drop away into an abyss, leaving
the voyagers motionless, and this illusion must, indeed, be probably
universal. It is the same illusion as the apparent gliding backwards of
objects to a traveller in a railway carriage; only in this latter case
the rattling and shaking of the carriage helps the mind to grasp the
real fact that the motion belongs to the train itself; whereas it is
otherwise with a balloon, whose motion is so perfectly smooth as to be
quite imperceptible.

Old ideas, formed upon insufficient observations, even if erroneous,
were slow to die. Thus it used to be stated that an upper cloud floor
adapted itself to the contour of the land over which it rested, giving
what Mr. Monck Mason has called a "phrenological estimate" of the
character of the earth below; the clouds, "even when under the influence
of rapid motion, seeming to accommodate themselves to all variations of
form in the surface of the subjacent soil, rising with its prominences
and sinking with its depressions." Probably few aeronauts of the present
time will accept the statement.

It used commonly to be asserted, and is so often to this day, that a
feeling as of sea-sickness is experienced in balloon travel, and the
notion has undoubtedly arisen from the circumstances attending an ascent
in a captive balloon. It were well, now that ballooning bids fair to
become popular, to disabuse the public mind of such a wholly false idea.
The truth is that a balloon let up with a lengthy rope and held captive
will, with a fitful breeze, pitch and sway in a manner which may induce
all the unpleasant feelings attending a rough passage at sea. It may
do worse, and even be borne to earth with a puff of wind which may
come unexpectedly, and considerably unsettle the nerves of any holiday
passenger. I could tell of a "captive" that had been behaving itself
creditably on a not very settled day suddenly swooping over a roadway
and down into public gardens, where it lay incontinently along the
ground, and then, before the astonished passengers could attempt to
alight, it was seized with another mood, a