-west lay, as far as the eye could reach, a boundless expanse of
dense forest and jungle and swamp, a gloomy and forbidding-looking
region which it would be well-nigh impossible to traverse on foot.

Early in the afternoon the four voyagers were gathered in the
deck-saloon, closely examining a somewhat rudely-drawn chart that was
spread out on the table. It was the map that formed part of the
manuscript which had been found in the car of Louis Holt's miniature
balloon, and sketched out his route from Zanzibar to Aeria, and the
country lying round so far as he had been able to observe it.

"This gives us, after all, very little idea of the distance we have
yet to go," said Arnold; "for though Holt has got his latitude
presumably right, we have very little clue to his longitude, for he
says himself that his watch was stopped in a thunder-storm, and that
in the same storm he lost all count of the distance he had travelled.
Added to that, he admits that he was blown about for twelve days in
one direction and another, so that all we really know is that
somewhere across this fearful wilderness beneath us we shall find
Aeria, but where is still a problem."

"What is your own idea?" asked Colston.

"Not a very clear one, I must confess. At this elevation we can see
about sixty miles as the atmosphere is now, and as far as we can see
to the south-west there is nothing but the same kind of country that
we have under us. We have travelled rather more than 2700 miles since
we left the Hindu Kush, and according to my reckoning Aeria lies
somewhere between 3000 and 3200 miles south-west of where we started
from on Thursday morning. That means that we are within between three
and five hundred miles of Aeria, unless, indeed, our calculations are
wholly at fault, and at that rate, as we only have about four and a
half hours' daylight left, we shall not get there to-day at our
present speed."

"Couldn't we go a bit faster?" put in Natasha. "You know I and the
Princess are dying to see this mysterious unknown country that only
two other people have ever seen."

"You have but to say so, Natasha, and it is already done," replied
Arnold, signalling at the same moment to the engine-room by means of
a similar arrangement of electric buttons to that which was in the
wheel-house. "Only you must remember that you must not go out on deck
now, or you will be blown away like a feather into space."

While he was speaking the three propellers