a valve. The intention was by compression of the air in the
cushion and the inner balloon, to alter the height of the
airship, in order to travel with the most favourable air
currents. The motive power was 20 oar propellers worked by men.

This airship proved to be too heavy on completion to lift its own
weight, and was destroyed by the onlookers.

The next airship, the Dupuy de Lome, is of interest because the
experiments were carried out at the cost of the State by the
French Government. This ship consisted of a spindle-shaped
balloon with a length of 112 feet, diameter of 48 1/2 feet and a
volume of 121,800 cubic feet. An inner air balloon of 6,000
cubic feet volume was contained in the envelope. The method of
suspension was by means of diagonal ropes with a net covering. A
rudder in the form of a triangular sail was fitted beneath the
envelope and at the after part of the ship. The motive power was
double-winged screws 29 feet 6 inches diameter, to be worked by
four to eight men.

On her trials the ship became practically a free balloon, an
independent velocity of about six miles per hour being achieved
and deviation from the direction of the wind of ten degrees.

At the close of the nineteenth century Santos-Dumont turned his
attention to airships. The experiments which he carried out
marked a new epoch and there arose the nucleus of the airship as
we know it to-day. Between the years 1898 and 1905 he had in all
built fourteen airships, and they were continually improved as
each succeeding one made its appearance. In the last one he