thereby. The airship
had a greater range of vision and a better downward view than any
sea-vessel; it could travel more slowly, watch more closely, stay out
much longer, than any other vessel of the air. The British credit
their airships with several successful attacks on submarines, but they
give them a far greater place in causing a fear among the under-sea
boats which drove them beneath the surface and greatly limited their
efficiency.

The German Zeppelins, on the other hand, stand out in public
imagination as a failure in the war, especially because the British
shortly established an airplane barrage which proved to be their
masters. This view is correct only in so far as it applies to interior
raiding, for which, indeed, the Zeppelin was not designed. How untrue
it is of the Zeppelin as the outpost for the German fleet British
officers will readily admit. Indeed, they credit them with the escape
of the German fleet at Jutland, one of the deepest regrets in British
naval history. As eyes for the German fleet in the North Sea, the
Zeppelins, with their great cruising range and power of endurance,
proved almost invaluable.

Airships have, then, behind them a rich heritage and before them a
bright future. Much work that the airplane can do they cannot do;
while, on the other hand, much work that they can do the airplane
cannot. The two services are essentially different and yet essentially
complementary. Between them they offer nearly every facility and
method of travel in the air which could be desired. Each must be
equally developed in order to increase the efficiency and the value of
the other.

The great difference, of course, between the airplane and the airship
is that the former sustains itself as a heavier-than-air vessel by the
lifting power of the air in relation to a body driven hard against it
by its powerful engines, while the latter sustains itself as a
lighter-than-air body because of the large amount of air displaced by
a huge envelop loaded with gas much lighter than the air itself. The
contrast is obvious; one vessel is small, agile, and very fast; the
other is slow and clumsy. The airship cannot attain anything like the
speed of the airplane, nor can it go so high or maneuver so quickly,
but on the other hand, at least for the immediate present, it can stay
afloat very much longer and carry much greater weight.

Moreover, the airship has certain other easily perceptible advantages
over the air