Evening star., 1925-01-17

gleam IN the chief mild eyes as he
turned the handle of the stop-cock
to the gauge. The hand of the dial
| trembled violently, then swung to 40
atmospheres indicated, where it re-
| mained steady!
Forty atmospheres" the master
said quietly. IA great reservoir. All,
Seton, it is almost sacrilege to tap 1t
the product of natures slow proc
esses through cons of time"
And now a trip to the outer world
became urgent We were short of
the stores and plant made necessary
by our development of the caves re-
sources. Again, we had TO complete
the airship design In the light of the
new gas. The chief made tests OF a
sample drawn straight from the res
ervoir and found 1t to be almost pure
aithon. The specific gravity of the
mixture he declared to be close on
five times less than that of hydrogen,
so that with our design for a helium-
lifted ship our margin for play was
enormous.
In the original design the total
fixed weight worked out at about
30, 900 Kilograms. with a dispOSable
lift of under 10000. The small pro-
weight was due to strengthening OF
the structure and the sacrifice of
carrying capacity to that end. 1t was
not anticipated that we should have
to carry heavy armament or bombs
or that sort OF thing, or a very nu-
merous crew.
With the advantages OF the much
lighter aithon l urged the master to
permit a further stiffening of the
structure, and he agreed. We thus
avoided the weaknesses which have
always chara cterized even the best of
rigid dirigibles. The length and
mold of the vessel we did not alter
She has designed to zoo meters in
length over all, % meters in diam
eter, with an extreme height of %.
In cross-section she was 12-sided
and foared with one Of the facets as
broad keel. This gave her fiat
top and two vertical facets, one on
either side. We joined the angles of
these horizontal and vertical facets,
each to the angle squarely opposite,
with latticed girders Of duralumin, so
that the structure of the vessel was
in fact broad hollow gtrder of cross
shaped section through all her length.
Her body was short and parallel,
with long rounded bows and an ex-
tended taperlng stern, the duodecago-
nal section being held throughout.
The cross-shaped section of the
longitudinal girdcr permitted the
running of Il chamber. seven meters
wide, from the point where her bows
began to round to that where she be
gan to taper 10 the stern, length of
go meters. on the main EangWay.
or eel, level, this chamber was di-
vic ed off as follows. from fore to aft:
first the room holding the control
connections from the navigating cab
in which was suspended below, the
two being joined by a ladder; next
two sleeping cabins side by side in
tended for the chief and myself; be-
hind these cabins, further aft, a big
ger companionway ran down into the
nayiga ton room; next space lead
ing into an alleyway which had cubi-
cleS on either side to the number of
Il. each cubicle taking two men and
being provided with two low berths
and two lockers; next canfe the en-
gine room with the power for work
ing the gas taps and so on, for raising
and lowering a gondola to and from
the main structure of the ship. and
also for creating the enormously high
voltage electr lefty necessary for some
OF the chiefs marvellous instruments;