OVER THE VOLCANO




The sea was as rough as ever, and the symptoms became alarming. The
barometer fell several millimeters. The wind came in violent gusts,
and then for a moment or so failed altogether. Under such
circumstances a sailing vessel would have had to reef in her topsails
and her foresail. Everything showed that the wind was rising in the
northwest. The storm-glass became much troubled and its movements
were most disquieting.

At one o'clock in the morning the wind came on again with extreme
violence. Although the aeronef was going right in its teeth she was
still making progress at a rate of from twelve to fifteen miles an
hour. But that was the utmost she could do.

Evidently preparations must be made for a cyclone, a very rare
occurrence in these latitudes. Whether it be called a hurricane, as
in the Atlantic, a typhoon, as in Chinese waters a simoom, as in the
Sahara, or a tornado, as on the western coast, such a storm is always
a gyratory one, and most dangerous for any ship caught in the current
which increases from the circumference to the center, and has only
one spot of calm, the middle of the vortex.

Robur knew this. He also knew it was best to escape from the cyclone
and get beyond its zone of attraction by ascending to the higher
strata. Up to then he had always succeeded in doing this, but now he