itudes. This was another observation--of Uncle Prudent's--a
new inexplicable phenomenon.

"Couldn't we get up to the window and see where we are?"

"We might," said Uncle Prudent. "Frycollin, get up!"

The Negro arose.

"Put your back against the wall," continued Prudent, "and you, Evans,
get on his shoulders while I buttress him up."

"Right!" said Evans.

An instant afterwards his knees were on Frycollin's shoulders, and
his eyes were level with the window. The window was not of lenticular
glass like those on shipboard, but was a simple flat pane. It was
small, and Phil Evans found his range of view was much limited.

"Break the glass," said Prudent, "and perhaps you will be able to see
better."

Phil Evans gave it a sharp knock with the handle of his bowie-knife.
It gave back a silvery sound, but it did not break.

Another and more violent blow. The same result.

"It is unbreakable glass!" said Evans.

It appeared as though the pane was made of glass toughened on the
Siemens system--as after several blows it remained intact.

The light had now increased, and Phil Evans could see for some
distance within the radius allowed by the frame.

"What do you see?" asked Uncle Prudent.

"Nothing."

"What? Not any trees?"

"No."

"Not even the top branches?"

"No."

"Then we are not in the clearing?"

"Neither in the clearing nor in the park."

"Don't you see any roofs of houses or monuments?" said Prudent, whose
disappointment and anger were increasing rapidly.

"No."

"What! Not a flagstaff, nor a church tower, nor a chimney?"

"Nothing but space."

As he uttered the words the door opened. A man appeared on the
threshold. It was Robur.

"Honorable balloonists" he said, in a serious voice, "you are now
free to go and come as you like."

"Free!" exclaimed Uncle Prudent.

"Yes--within the limits of the "Albatross!"

Uncle Prudent and Phil Evans rushed out of their prison. And what did
they see?

Four thousand feet below them the face of a country they sought in
vain to recognize.

Chapter VII

ON BOARD THE ALBATROSS

"When will man cease to crawl in the depths to live in the azure and
quiet of the sky?"

To this question of Camille Flammarion's the answer is easy. It will
be when the progress of mechanics has enabled us to solve the problem
of aviation. And in a few years--as we can foresee--a more
practical utilization of electricity will do much towards that
solution.