That gave rise to a question in my mind.

How would the commander of this floating dwelling-place proceed?
Would he obtain air by chemical means, in getting by heat the oxygen contained in chlorate of potash, and in absorbing carbonic acid by caustic potash?
Or--a more convenient, economical, and consequently more probable alternative--would he be satisfied to rise and take breath at the surface of the water, like a whale, and so renew for twenty-four hours the atmospheric provision?
In fact, I was already obliged to increase my respirations to eke out of this cell the little oxygen it contained, when suddenly I was refreshed by a current of pure air, and perfumed with saline emanations.

It was an invigorating sea breeze, charged with iodine.

I opened my mouth wide, and my lungs saturated themselves with fresh particles.
At the same time I felt the boat rolling.

The iron-plated monster had evidently just risen to the surface of the ocean to breathe, after the fashion of whales.