The Londonderry sifter. (South Londonderry, Vt.) 1883-19??, 1893-10-27
TEN MILES ABOVE EARTH.
Interesting Experiments at the Highest
Point Balloon Ever Reached.

Point u Balloon Ever Reached.
One of the most interesting expert
ments with balloons that has ever been
undertaken was that of Messrs. Hermite
and Besancon at Paris-Vaugirard. They
succeeded in sending balloon to the
unprecedented elevation of 16, 900 meters,
or about 10 miles! There were no peo-
pie in the balloon, but it carried va
riety of self registering instruments de-
signed to record the temperature, the
atmospheric pressure, etc. The little
balloon was started on its lofty trip
about noon, when the air was remark
ably still and clear. n rose rapidly and
In three-quarters of an hour had attained
an elevation of 10 miles, at which height
it remained for several hours.
1t was there subjected to an atmos-
pheric pressure only about one-eighth as
great as that at the surface of the earth,
and M. Hermite explains its floating for
so long a time at constant height by
supposing that the temperature does not
vary sensibly with the elevation of the
floating body after the latter has at
tanned an altitude where seven-eighths
of the atmospheric pressure is lacking
and where there remains no trace of wa
ter vapor.
But toward o'clock, when with the
decline of day the temperature began
rapidly to fall, the balloon started back
toward the earth, arriving with gentle
motion, which did not disturb the instru-
ments it carried, at I'll at Chanvres,
near Paris Vanguard, from which it had
started.
The balloon was visible with a tele-
scope during the entire time. 1t shone
like the planet Venus, seen. by day. By
means of micrometer attached to an
astronomical telescope, the apparent di-
ameter of the balloon could easily have
been measured, and this would have fur
nished means of calculating it's alti-
tude independent of the record of the
barometer which it carried.
The barometer and thermometer were
furnished with automatic pens driven by
clockwork, by means of which diagrams
Of the changes of pressure and tempera-
ture that the balloon experienced were
obtained. At the height Of about u
miles the thermometer marked tenn
perature of 60 degrees F. below zero.
Then the ink in the registering pens of
both the thermometer and the barom-
eter became frozen and the records were
interrupted.
But as the balloon continued to rise
the ink was thawed again, and at the 10
mile level the automatic records were re-
| newed. The temperature registered there
was only about degrees below zero.
| The increase of temperature is ascribed
to the effect of the unclouded sun heat
ing the air in the basket that contained
the instruments. The lowest record OF
the barometer was 1903 millimeters, or a
| trifle more than four inches.
M. Hermite calls attention to the fact
that the density of the air at the height
of 10 miles, where the balloon remained
during most of the afternoon, is less
than that existing upon the plains of the
moon, on the assumption that the at
mospheric density on the moon is pro
portional to the force Of gravity at the
surface of that orb.
If this is correct, then the instruments
would have behaved about the same il
M. Hermite had been able to place them
on the moon, as they did when he sent
them only 10 miles above the earth
Youths Companion.