ve_, the _Argus_
(which was the first ship to be fitted with a flush deck), the _Eagle_,
and the new _Hermes_, which last two ships were unfinished at the time
of the armistice.

In this matter of aerial work for the navy the whole period of the war
was a period of experiment rather than achievement. The conditions of
experiment were hard enough, when all the shipyards and factories of the
country were working at full pressure in the effort to make good our
heavy losses in merchant shipping. Yet experiment continued, and
progress was made. Three new forms of aircraft deserve special mention.
The kite balloon, the small improvised airship called the submarine
scout, and last, though not least, the flying boat, were all invented or
brought into use by the Naval Air Service during the course of the war.

For stationary aerial observation the means employed in England, before
the war, were the captive spherical balloon and the man-lifting kite.
Many successful experiments with the man-lifting kite, or groups of
kites, had been carried out, especially by Major B. F. S. Baden-Powell,
during the closing years of the nineteenth century. But both the balloon
and the kite had serious faults. The kite cannot be efficiently operated
in a wind of less than twenty miles an hour, and the spherical balloon
cannot be operated in a wind of more than twenty miles an hour. The
balloon except in the lightest of breezes, and the kite at all times,
give a very unsteady platform for observation, so that field-glasses are
difficult to use. The merits of both kite and balloon were combined and
the faults of both were remedied in the kite balloon. The attachment of
a kite to the upper hemisphere of an ordinary spherical balloon, on the
cable side, to prevent the balloon from rotating in a wind, had been
proposed by a private inventor as early as 1885, but nothing came of it.
The kite balloon which was used in the war was invented in 1894 by Major
von Parseval, the German airship designer, and Captain von Sigsfeld.
This balloon is sausage shaped; the cable is attached to the forward
portion; the rear end carries an air-rudder, and is weighted down by the
car, or basket. Extending outwards at right angles on both sides of the
rear portion of the balloon is a wind-sail which does the office of a
kite and assists in preventing the rudder end of the balloon from being
too much depressed by the weight of the car. The balloon is divided into
two segmen