Democratic messenger., 1894-03-17
TEN MILES up!
a Balloon Ten Miles Up iiI
the Sky-An Uuprece.
deuted Trip.
THE BAROMETER FREEZES.
Hut as the Balloon Continues
to Ascend the BarOue-
ter ThaWs Out.

One of the most interesting expert
ments with balloons that has ever been
undertaken was that of .lessrs. Hermite
and Besancon at Paris s-NaugIrard. They
succeeded in sending balloon to the
unprecedented elevation of ID. OOO meters,
or about 10 miles. There We're no peo-
pie in the balloon. but 1t 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. II rose rapidly and
in three-quarters of AN hour had attained
an elevation of 10 miles. at which height
It remained for several hours.
Ii was there subjected To an atmos-
pheric pressure only about one eighth as
great as that at the surface Ut the earth,
and NJ. Hermite explains its floating for
SO long a time ut u constant height by
supposing that the temperature does not
vary sensibly with the elevation of the
floating body after the latter has at
taIn,d all 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 a gentle
motion, which did not disturb the instru-
ments it carried, at 7:ll at Chanvres.
near Paris Vaugirard. from which it had
started.
The balloon was visible with u tele-
scope during the entire time. Ii shone
like the planet Venus, seen by day. BY
means of "a 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 its 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
peraturc of Gu 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 8 degrees below zero.
The increase of temperature is ascribed
to the effect of the unclouied sun heat
ing the air in the basket that contained
the instruments. The lowest record of
the barometer was lO3 millimeters, or y
trifie more than four inches.
NJ. 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.
II this is correct. then the instruments
would have behaved about the same if
NJ. Hermite had been able to place them
Oh the moon, as they did when he sent
them only 10 miles above the GARTH
Youths Companion.