an of which what is now the Sahara
was probably the deepest part, Aeria was one of the many islands that
had risen above its surface; and that, as the land rose and the
waters subsided, its peculiar shape had prevented the forms of life
which it contained from migrating or becoming modified in the
struggle for existence with other forms, just as the flora and fauna
of Australia have been shut off from those of the rest of the world.

There were no traces of human inhabitants to be found; but there were
apparently two or three families of anthropoid apes, that seemed, so
far as Holt had been able to judge--for they were extremely shy and
cunning, and therefore difficult of approach--to be several degrees
nearer to man, both in structure and intelligence, than any other
members of the Simian family that had been discovered in other parts
of the world.

As may well be imagined, a month passed rapidly and pleasantly away,
what with exploring excursions by land and air, in the latter of
which by no means the least diverting element was the keen and
quaintly-expressed delight of Louis Holt at the new method of travel.
Two or three times Arnold had, for his satisfaction, sent the _Ariel_
flying over the ridge across which she had entered Aeria, but he had
always been content with a glimpse of the outside world, and was
always glad to get back again to the "happy valley," as he invariably
called his isolated paradise.

The brief sojourn in this delightful land had brought back all the
roses to Natasha's lovely cheeks, and had completely restored both
her and the Princess to the perfect health that they had lost during
their short but terrible experience of Russian convict life; but
towards the end of the month they both began to get restless and
anxious to get away to the rendezvous with the steamer that was
bringing their friends and comrades out from England.

So it came about that an hour or so after sunrise on Friday, the 20th
of May, the company of the _Ariel_ bade farewell for a time to Louis
Holt and his companion, leaving with them a good supply of the
creature comforts of civilisation which alone were lacking in Aeria,
rose into the air, and disappeared over the ridge to the north-west.

They had rather more than 2500 miles of plain and mountain and desert
to cross, before they reached the sea-coast on which they expected to
meet the steamer, and Arnold regulated the speed of the _Ariel_ so
that they would reach