could not leave the ground. After several experiments the
inventor succeeded in ascending, when he obtained a speed against
the wind of about 6 miles an hour.

A balloon of great historical interest was that invented by
Dtipuy du Lonie, in the year 1872. Instead of using steam he
employed 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