The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1878-11-13

matter. PROF. ". knight IN Nineteenth
Century. ..# e. a.....
Military Balloonlng.
1t is the difficulty of securing suffi
cheney of gas for initiation that OF present
stands in the way Of employing balloons
III the field. The French balloons are all
large. ones, for they were constructed
most of them, for postal service during
the serge and, besides the mails and aer.
onaut sometimes carries three passengers
With the exception of half dozen, all
the balloons which left Paris had uni
form capacity Of 1000 cubic metres, whik
one, in which M. De Fonvielle and three
other persons travelled from Paris tc
Louvain, measures 5000 metres. Such
bulky balloons as these are unsuited 70,
the field, where the problem is to send 8
single observer aloft with the minimum
amount of time and trouble. The small.
est balloon and the lightest gas for the
purpose are what the soldier seems to re.
quire, and it is toward these two points
that attention has lately been directed by
Capt. Tcmplar and the other officers
who are just now occupied in the
study OF aerial navigation in this
country. Naturally enough, hydrogen
holds out the most promising features as
q lifting medium, and it is with this gas
that experiments are once more to be
made. AS our readers remember, the
weight Ct hydrogen is calculated to be
2.14 grains per 100 cubic inches, while
air, On the other hand, weighs 81 grains;
and as the lifting power is represented by
the difference between these numbers, it
stands to reason that theoretically bal
loon, if filled with hydrogen, need be of
but comparatively small dimentions. Un
fortunately, in practical affair like bal
loning, lot of accidental matter requires
to be taken into consideration, and two
OF these are the facts that it is difficult to
secure pure hydrogen, and more difficult
still to keep 1t in the balloon envelope
when secured. Capt. Templar is sangu-
inc that 10000 cubic feet balloon is
quite capable of lifting an observer high
enough for reconnoitring purposes, if
filled with hydrogen, and well-nigh
proved his case, the other day when
he overcome gravity, if he did not rise.
with the aid of light coal gas with
which this small balloon was filed. The
coal-gas, specially manufactured for his
balloon, and had lifting power of so
pounds per 1000 feet, SO that total of
500 pounds was here at his disposal. As
we have said, this was insufficient for an
ascent, for, besides the weight of the
aeronaut, there are, it must be remem-
bered, envelope, car, tackle, cable, and
ballast to be taken into. consideration.
Instead of 500 pounds, hydrogen of the
same volume would have supplied lift.
power Of 700 pounds, and this Of course
would have been ample, and to spare, for
an ascent. But perhaps tie most inter
esting feature of the present ballooning
experiment will be the trial of compress
ed gas. As our readers know very well,
compressed gases arc now commercial
article in thus country, and you may pur-
chase cylinders of oxygen or hydrogen
1t 20 atmospheres pressure. 2 As our Roy
al Engineers carry about with them in
the field such unwieldy things as pom
tons, they can hardly grumb bic ut a wagon
load Of hydrogen tubes, and with these il
is suggested to fill Q balloon just wherev-
er . reconnaissance IS to be made. On
nearing the enemy the first convenient
spot will be chosen for the manufacture
of hydrogen, and this will be compressed
with the assistance of suitable apparatus,
into the tubes, to be drawn OF again
when the ascent is to be made. In this
way there is always 10 be gas at hand not
only to fill the balloon but to keep up 4
constant supply for limited period,
since hydrogen, under the most favorable
circumstances rapidly exudes from 4
balloo N envelope. a military balloon, II
appears to be decided, must be : captive
1ne. Nature. Fasi4h4g basi II 1nga.
Tho policy of China favors agriculture
more than all other employments. IN
china tho 0On1 ifioy,F r,f n