<h2 id="sigil_toc_id_47">CHAPTER XXIII.</h2>
<h3 id="sigil_toc_id_48">THE PROJECTILE-VEHICLE.</h3>
<p>On the completion of the Columbiad the public interest centred in
the projectile itself, the vehicle which was destined to carry the
three hardy adventurers into space.</p>
<p>The new plans had been sent to Breadwill and Co., of Albany, with
the request for their speedy execution. The projectile was
consequently cast on the 2d November, and immediately forwarded by
the Eastern Railway to Stones Hill, which it reached without accident
on the 10th of that month, where Michel Ardan, Barbicane, and Nicholl
were waiting impatiently for it.</p>
<p>The projectile had now to be filled to the depth of three feet
with a bed of water, intended to support a watertight wooden disc,
which worked easily within the walls of the projectile. It was upon
this kind of raft that the travellers were to take their place. This
body of water was divided by horizontal partitions, which the shock
of the departure would have to break in succession. Then each sheet
of the water, from the lowest to the highest, running off into escape
tubes toward the top of the projectile, constituted a kind of spring;
and the wooden disc, supplied with extremely powerful plugs, could
not strike the lowest plate except after breaking successively the
different partitions. Undoubtedly the travellers would still have to
encounter a violent <i>recoil</i> after the complete escapement of
the water; but the first shock would be almost entirely destroyed by
this powerful spring. The upper part of the walls were lined with a
thick padding of leather, fastened upon springs of the best steel,
behind which the escape tubes were completely concealed; thus all
imaginable precautions had been taken for averting the first shock;
and if they <i>did</i> get crushed, they must, as Michel Ardan said,
be made of very bad materials.</p>
<div class="illus"><ANTIMG alt="Illustration: THE ARRIVAL OF THE PROJECTILE AT STONE'S HILL." id="arrival" src="images/arrival.jpg" /></div>
<div class="caption">THE ARRIVAL OF THE PROJECTILE AT STONE'S
HILL.</div>
<p>The entrance into this metallic tower was by a narrow aperture
contrived in the wall of the cone. This was hermetically closed by a
plate of aluminium, fastened internally by powerful screw-pressure.
The travellers could therefore quit their prison at pleasure, as soon
as they should reach the moon.</p>
<p>Light and view were given by means of four thick lenticular glass
scuttles, two pierced in the circular wall itself, the third in the
bottom, the fourth in the top. These scuttles then were protected
against the shock of departure by plates let into solid grooves,
which could easily be opened outwards by unscrewing them from the
inside. Reservoirs firmly fixed contained water and the necessary
provisions; and fire and light were procurable by means of gas,
contained in a special reservoir under a pressure of several
atmospheres. They had only to turn a tap, and for six hours the gas
would light and warm this comfortable vehicle.</p>
<p>There now remained only the question of air; for allowing for the
consumption of air by Barbicane, his two companions, and two dogs
which he proposed taking with him, it was necessary to renew the air
of the projectile. Now air consists principally of twenty-one parts
of oxygen and seventy-nine of nitrogen. The lungs absorb the oxygen,
which is indispensable for the support of life, and reject the
nitrogen. The air expired loses nearly five per cent. of the former
and contains nearly an equal volume of carbonic acid, produced by the
combustion of the elements of the blood. In an air-tight enclosure,
then, after a certain time, all the oxygen of the air will be
replaced by the carbonic acid—a gas fatal to life. There were two
things to be done then—first, to replace the absorbed oxygen;
secondly, to destroy the expired carbonic acid; both easy enough to
do, by means of chlorate of potassium and caustic potash. The former
is a salt which appears under the form of white crystals; when raised
to a temperature of 400° it is transformed into chlorate of potass,
and the oxygen which it contains is entirely liberated. Now
twenty-eight pounds of chlorate of potassium produce seven pounds of
oxygen, or 2400 <i>litres</i>—the quantity necessary for the
travellers during twenty-four hours.</p>
<p>Caustic potash has a great affinity for carbonic acid; and it is
sufficient to shake it in order for it to seize upon the acid and
form bi-carbonate of potass. By these two means they would be enabled
to restore to the vitiated air its life-supporting properties.</p>
<p>It is necessary, however, to add that the experiments had hitherto
been made <i>in anima vili</i>. Whatever its scientific accuracy was,
they were at present ignorant how it would answer with human beings.
The honour of putting it to the proof was energetically claimed by J.
T. Maston.</p>
<p>"Since I am not to go," said the brave artillerist, "I may at
least live for a week in the projectile."</p>
<p>It would have been hard to refuse him; so they consented to his
wish. A sufficient quantity of chlorate of potassium and of caustic
potash was placed at his disposal, together with provisions for eight
days. And having shaken hands with his friends, on the 12th November,
at six o'clock a.m., after strictly informing them not to open his
prison before the 20th, at six o'clock p.m., he slid down the
projectile, the plate of which was at once hermetically sealed. What
did he do with himself during that week? They could get no
information. The thickness of the walls of the projectile prevented
any sound reaching from the inside to the outside. On the 20th of
November, at six p.m. exactly, the plate was opened. The friends of
J. T. Maston had been all along in a state of much anxiety; but they
were promptly reassured on hearing a jolly voice shouting a
boisterous hurrah.</p>
<p>Presently afterwards the secretary of the Gun Club appeared at the
top of the cone in a triumphant attitude. He had grown fat!</p>
<div class="illus"><ANTIMG alt="Illustration: J. T. MASTON HAD GROWN FAT." id="fat" src=
"images/fat.jpg" /></div>
<div class="caption">J. T. MASTON HAD GROWN FAT.</div>
<div style="break-after:column;"></div><br />