surface area,
and the fact that it is attached to the hull in such a way as to admit
of its being turned freely in any direction, thus dispensing with all
necessity for a rudder."

"Why have you left the hull unpainted, professor? I suppose you had
some good reason for so doing?" remarked the colonel, chiming into the
conversation.

"I had no less than _three_ good reasons for leaving the hull of the
ship unpainted," answered the professor. "In the first place, aethereum
is quite insensible to the attacks of air and water--it never oxidises,
and paint was therefore unnecessary for its preservation. In the next
place, the quantity of paint necessary to cover that enormous surface
would weigh something considerable; and, as I have throughout the work
taken the utmost pains to keep down all the weight to the lowest ounce
consistent with absolute safety, I rejected it on that account. And
lastly, I take it that we are anxious to avoid all unnecessary
observation; and I believe this cannot be better accomplished than by
preserving the brilliant metallic lustre of the hull, which, especially
when we are floating in mid-air, will reflect the tints of the
surrounding atmosphere, and so make it almost impossible to distinguish
us."

"Except when the sun's rays fall directly upon us, eh, professor?"
remarked Mildmay.

"In that case," returned the professor, "observers will see a dazzling
flash of light in which all shape will be indistinguishable."

"And we shall thus be mistaken for a meteorite," exclaimed the baronet
somewhat sarcastically. "Excellent! admirable! I really must
congratulate you, professor, upon the wonderful foresight with which you
seem to have provided for every possible and impossible emergency. Now,
what is the next marvel?"

"There is nothing more down here. We will now proceed on board, if you
please, gentlemen," said the professor; and he forthwith led the way up
a ladder which leaned against the vessel's lofty side. This conducted
them as far as the upper curve of her cylindrical bilge, at which point
they encountered a flight of light ornamental openwork steps permanently
attached to the ship's side, up which they passed to the gangway in the
stout metal railing which served instead of bulwark, and so reached the
spacious promenade deck. Looking down into the yard from this coign of
vantage, they seemed to be an enormous height from the ground; and the
baronet shrugged his shoulders mo