In some instances, and where the military department is possessed
of an elaborate equipment such as characterises the German army,
when reconnaissance is completed and the balloon is to be removed
to another point, the gas is pumped back into the cylinders for
further use. Such an economical proceeding is pretty and well
adapted to manoeuvres, but it is scarcely feasible in actual
warfare, for the simple reason that the pumping takes time.
Consequently the general procedure, when the balloon has
completed its work, is to permit the gas to escape into the air
in the usual manner, and to draw a fresh supply of gas from
further cylinders when the occasion arises for re-inflation.

Although the familiar spherical balloon has proved perfectly
adequate for reconnoitring in the British and French armies, the
German authorities maintained that it was not satisfactory in
anything but calm weather. Accordingly scientific initiative was
stimulated with a view to the evolution of a superior vessel.
These endeavours culminated in the Parseval-Siegsfeld captive
balloon, which has a quaint appearance. It has the form of a
bulky cylinder with hemispherical extremities. At one end of the
balloon there is a surrounding outer bag, reminiscent of a
cancerous growth. The lower end of this is open. This
attachment serves the purpose of a ballonet. The wind blowing
against the opening, which faces it, charges the ballonet with
air. This action, it is claimed, serves to steady the main
vessel, somewhat in the manner of the tail of a kite, thereby
enabling observations to be made as easily and correctly in rough
as in calm weather. The appearance of the balloon while aloft is
certainly curious. It appears to be rearing up on end, as if the
extremity saddled with the ballonet were weighted.