ich it ripped to pieces. The majestic
craft crumpled up and crashed to the ground, killing its crew in its
fall.

In the illustration facing p. 17, of a Lebaudy air-ship, we have a good
type of the semi-rigid craft. In shape it somewhat resembles an enormous
porpoise, with a sharply-pointed nose. The whole vessel is not as
symmetrical as a Zeppelin dirigible, but its inventors claim that
the sharp prow facilitates the steady displacement of the air during
flight. The stern is rounded so as to provide sufficient support for the
rear planes.

Two propellers are employed, and are fixed outside the car, one on
each side, and almost in the centre of the vessel. This is a some what
unusual arrangement. Some inventors, such as Mr. Spencer, place the
propellers at the prow, so that the air-ship is DRAWN along; others
prefer the propeller at the stern, whereby the craft is PUSHED along;
but M. Julliot chose the central position, because there the disturbance
of the air is smallest.

The body of the balloon is not quite round, for the lower part is
flattened and rests on a rigid frame from which the car is suspended.
The balloon is divided into three compartments, so that the heavier air
does not move to one part of the balloon when it is tilted.

In the picture there is shown the petrol storage-tank, which is
suspended immediately under the rear horizontal plane, where it is out
of danger of ignition from the hot engine placed in the car.

CHAPTER XII. A Non-rigid Balloon

Hitherto we have described the rigid and semi-rigid types of air-ships.
We have seen that the former maintains its shape without assistance
from the gas which inflates its envelope and supplies the lifting power,
while the latter, as its name implies, is dependent for its form partly
on the flat rigid framework to which the car is attached, and partly on
the gas balloon.

We have now to turn our attention to that type of craft known as a
NON-RIGID BALLOON. This vessel relies for its form ENTIRELY upon the
pressure of the gas, which keeps the envelope distended with sufficient
tautness to enable it to be driven through the air at a considerable
speed.

It will at once be seen that the safety of a vessel of this type depends
on the maintenance of the gas pressure, and that it is liable to
be quickly put out of action if the envelope becomes torn. Such an
occurrence is quite possible in war. A well-directed shell which pierced
the balloon would und