destined to produce oxygen,
was furnished with enough chlorate of potash for two months. It
necessarily consumed a large quantity of gas, for it was obliged to keep
the productive matter up to 100 deg.. But there was abundance of that also.
The apparatus wanted little looking after. It worked automatically. At
that high temperature the chlorate of potash changed into chlorine of
potassium, and gave out all the oxygen it contained. The eighteen pounds
of chlorate of potash gave out the seven pounds of oxygen necessary for
the daily consumption of the three travellers.

But it was not enough to renew the oxygen consumed; the carbonic acid
gas produced by expiration must also be absorbed. Now for the last
twelve hours the atmosphere of the bullet had become loaded with this
deleterious gas, the product of the combustion of the elements of blood
by the oxygen taken into the lungs. Nicholl perceived this state of the
air by seeing Diana palpitate painfully. In fact, carbonic acid
gas--through a phenomenon identical with the one to be noticed in the
famous Dog's Grotto--accumulated at the bottom of the projectile by
reason of its weight. Poor Diana, whose head was low down, therefore
necessarily suffered from it before her masters. But Captain Nicholl
made haste to remedy this state of things. He placed on the floor of the
projectile several receptacles containing caustic potash which he shook
about for some time, and this matter, which is very greedy of carbonic
acid, completely absorbed it, and thus purified the interior air.

An inventory of the instruments was then begun. The thermometers and
barometers were undamaged, with the exception of a minimum thermometer
the glass of which was broken. An excellent aneroid was taken out of
its padded box and hung upon the wall. Of course it was only acted upon
by and indicated the pressure of the air inside the projectile; but it
also indicated the quantity of moisture it contained. At that moment its
needle oscillated between 25.24 and 25.08. It was at "set fair."

Barbicane had brought several compasses, which were found intact. It
will be easily understood that under those circumstances their needles
were acting at random, without any constant direction. In fact, at the
distance the projectile was from the earth the magnetic pole could not
exercise any sensible action upon the apparatus. But these compasses,
taken upon the lunar disc, might show particular phenomena. In any ca