rly, whilst at other times the direction changed within
500 feet of the earth Sometimes directly opposite currents were met
with."

With regard to the velocity of upper currents, as shown by the travel
of balloons, when the distances between the places of ascent and descent
are measured, it was always found that these distances were very
much greater than the horizontal movement of the air, as measured by
anemometers near the ground.

CHAPTER XVI. SOME FAMOUS FRENCH AERONAUTS.

By this period a revival of aeronautics in the land of its birth had
fairly set in. Since the last ascents of Gay Lussac, in 1804, already
recorded, there had been a lull in ballooning enterprise in France, and
no serious scientific expeditions are recorded until the year 1850, when
MM. Baral and Bixio undertook some investigations respecting the upper
air, which were to deal with its laws of temperature and humidity,
with the proportion of carbonic acid present in it, with solar heat at
different altitudes, with radiation and the polarisation of light, and
certain other interesting enquiries.

The first ascent, made in June from the Paris Observatory, though a
lofty one, was attended with so much danger and confusion as to be
barren of results. The departure, owing to stormy weather, was hurried
and illordered, so that the velocity in rising was excessive, the net
constricted the rapidly-swelling globe, and the volumes of out-rushing
gas half-suffocated the voyagers. Then a large rent occurred, which
caused an alarmingly rapid fall, and the two philosophers were reduced
to the necessity of flinging away all they possessed, their instruments
only excepted. The landing, in a vineyard, was happily not attended with
disaster, and within a month the same two colleagues attempted a second
aerial excursion, again in wet weather.

It would seem as if on this occasion, as on the former one, there was
some lack of due management, for the car, suspended at a long distance
from the balloon proper, acquired violent oscillations on leaving the
ground, and dashing first against a tree, and then against a mast, broke
some of the instruments. A little later there occurred a repetition on
a minor scale of the aeronauts' previous mishap, for a rent appeared in
the silk, though, luckily, so low down in the balloon as to be of
small consequence, and eventually an altitude of some 19,000 feet
was attained. At one time needles of ice were encountered settli