a number of
men to propel the craft, and with this air-ship he hoped to communicate
with the besieged city of Paris.

His greatest speed against a moderate breeze was only about 5 miles
an hour, and the endurance of the men did not allow of even this speed
being kept up for long at a time.

Dupuy foreshadowed the construction of the modern dirigible air-ship by
inventing a system of suspension links which connected the car to
the envelope; and he also used an internal ballonet similar to those
described in Chapter X.

In the year 1883 Tissandier invented a steerable balloon which was
fitted with an electric motor of 1 1/2 horse-power. This motor drove
a propeller, and a speed of about 8 miles an hour was attained. It is
interesting to contrast the power obtained from this engine with that
of recent Zeppelin air-ships, each of which is fitted with three or four
engines, capable of producing over 800 horse-power.

The first instance on record of an air-ship being steered back to its
starting-point was that of La France. This air-craft was the invention
of two French army captains, Reynard and Krebs. By special and
much-improved electric motors a speed of about 14 miles an hour was
attained.

Thus, step by step, progress was made; but notwithstanding the promising
results it was quite evident that the engines were far too heavy
in proportion to the power they supplied. At length, however, the
internal-combustion engine, such as is used in motor-cars, arrived, and
it became at last possible to solve the great problem of constructing a
really-serviceable, steerable balloon.

CHAPTER IX. The Strange Career of Count Zeppelin

In Berlin, on March 8, 1917, there passed away a man whose name will be
remembered as long as the English language is spoken. For Count Zeppelin
belongs to that little band of men who giving birth to a work of
genius have also given their names to the christening of it; and so the
patronymic will pass down the ages.

In the most sinister sense of the expression Count Zeppelin may be said
to have left his mark deep down upon the British race. In course of time
many old scores are forgiven and forgotten, but the Zeppelin raids on
England will survive, if only as a curious failure. Their failure was
both material and moral. Anti-aircraft guns and our intrepid airmen
brought one after another of these destructive monsters blazing to the
ground, and their work of "frightfulness" was taken up by