the skids, or to
the wheels, so that the airship, in calm weather, may be able to rest,
like a sea bird, on the waves, if desired.

The blimp's balloon envelope must contain two smaller balloons, together
holding 19,250 feet of hydrogen gas. The idea, of course, is that if
anything happens to the major balloon--puncturing by gunfire or by other
mishap--the "balloonets" inside of it will keep the machine afloat.

The wingless aeroplane is suspended from the balloon by cables of
galvanized wire. There is a special arrangement by which the
"pilot"--the man who steers and operates the airship--can at any time
measure the pressure of hydrogen in the balloon, thus knowing what he
has to count on in the way of carrying power.

The front part of the blimp's car is occupied by the engine and
radiator, behind which is a bulkhead of sheet steel. In the rear of this
bulkhead sits the pilot, and behind him the "observer," who makes
sketches and takes notes of anything important that he sees. Behind the
observer are the tanks for fuel oil and 300 gallons of water ballast.
The body of the car is covered with aeroplane linen, save for the
engine, which is sheathed with sheet aluminum.

In order to hold whatever position in the air may be desired, the blimp
is equipped with two horizontal fins and three vertical fins. Not every
blimp, that is to say, but the pattern approved and required of
contractors by the Navy Department. These fins are made of wood and
light steel tubing, reinforced with wire, covered with aeroplane linen
rubber painted and finished with varnish.

THE "BLIMP" WELL EQUIPPED.

There are also two horizontal rudders and two vertical rudders, for
steering up and down or sidewise. They work on ball bearings. A blimp,
one should understand, is a fish in the ocean of air, a swimmer--just as
the aeroplane is a flyer, like the bird.

The blimp's "car" carries an electric storage battery to furnish lights.
The same battery energizes a searchlight for night scouting. A wireless
apparatus, for transmitting information to the shore station, is part of
the equipment.

The blimp, as already stated, is a sea scout. It is meant to be operated
from a base on shore--which base is in constant communication by
telegraph and wireless with the great radio stations that are strung all
along our coasts at intervals of 200 miles. These stations, in turn, are
in communication with the huge wireless outfit at Arlington (across the