ch Lieutenant Procope had thus become
the originator; but the very existence of them all was at stake, and the
design must be executed resolutely. For the success of the enterprise it
was absolutely necessary to know, almost to a minute, the precise time
at which the collision would occur, and Captain Servadac undertook the
task, by gentle means or by stern, of extracting the secret from the
professor.

To Lieutenant Procope himself was entrusted the superintendence of the
construction of the montgolfier, and the work was begun at once. It was
to be large enough to carry the whole of the twenty-three residents in
the volcano, and, in order to provide the means of floating aloft
long enough to give time for selecting a proper place for descent, the
lieutenant was anxious to make it carry enough hay or straw to maintain
combustion for a while, and keep up the necessary supply of heated air.

The sails of the _Dobryna_, which had all been carefully stowed away in
the Hive, were of a texture unusually close, and quite capable of being
made airtight by means of a varnish, the ingredients of which were
rummaged out of the promiscuous stores of the tartan. The lieutenant
himself traced out the pattern and cut out the strips, and all hands
were employed in seaming them together. It was hardly the work for
little fingers, but Nina persisted in accomplishing her own share of it.
The Russians were quite at home at occupation of this sort, and having
initiated the Spaniards into its mysteries, the task of joining together
the casing was soon complete. Isaac Hakkabut and the professor were
the only two members of the community who took no part in this somewhat
tedious proceeding.

A month passed away, but Servadac found no opportunity of getting at the
information he had pledged himself to gain. On the sole occasion when he
had ventured to broach the subject with the astronomer, he had received
for answer that as there was no hurry to get back to the earth, there
need be no concern about any dangers of transit.

Indeed, as time passed on, the professor seemed to become more and more
inaccessible. A pleasant temperature enabled him to live entirely in his
observatory, from which intruders were rigidly shut out. But Servadac
bided his time. He grew more and more impressed with the importance of
finding out the exact moment at which the impact would take place,
but was content to wait for a promising opportunity to put any fresh
qu