oon
as is generally used in warfare at every available opportunity. It is
possible that the peculiar circumstances of the investment of the town
rendered such reconnaissance of comparatively small value. But, at
any rate, it seems clear that due opportunity was not given to this
strategic method. M. Giffard, who at the commencement of the siege was
in Paris, and whose experience with a captive balloon was second to
none, made early overtures to the Government, offering to build for
L40,000 a suitable balloon, capable of raising forty persons to a
height of 3,000 feet. Forty aerial scouts, it may be said, are hardly
needed for purposes of outlook at one time; but it appears that this was
not the consideration which stood in the way of M. Giffard's offer
being accepted. According to M. de Fonvielle, the Government refused the
experienced aeronaut's proposal on the ground that he required a place
in the Champs Elysees, "which it would be necessary to clear of a few
shrubs"!

CHAPTER XIX. THE TRAGEDY OF THE ZENITH--THE NAVIGABLE BALLOON

The mechanical air ship had, by this time, as may be inferred, begun
seriously to occupy the attention of both theoretical and practical
aeronauts. One of the earliest machines deserving of special mention was
designed by M. Giffard, and consisted of an elongated balloon, 104 feet
in length and 39 feet in greatest diameter, furnished with a triangular
rudder, and a steam engine operating a screw. The fire of the engine,
which burned coke, was skilfully protected, and the fuel and water
required were taken into calculation as so much ballast to be gradually
expended. In this vessel, inflated only with coal gas, and somewhat
unmanageable and difficult to balance, the enthusiastic inventor
ascended alone from the Hippodrome and executed sundry desired
movements, not unsuccessfully. But the trial was not of long duration,
and the descent proved both rapid and perilous. Had the trial been made
in such a perfect calm as that which prevailed when certain subsequent
inventions were tested, it was considered that M. Giffard's vessel
would have been as navigable as a boat in the water. This unrivalled
mechanician, after having made great advances in the direction of high
speed engines of sufficient lightness, proceeded to design a vastly
improved dirigible balloon, when his endeavours were frustrated by
blindness.

As has been already stated, M. Dupuy de Lome, at the end of the siege of
Par