I have carefully considered everything, positively everything, connected with the safety of such a descent.

The air in the cavity where my shell now rests is perfectly good; I have tested it.

The temperature is simply warm, and there is no danger of quicksands or anything of that sort, for my shell still rests as immovable as when I first saw it below the bottom of the shaft.
"As to the distance I should have to descend, when you come to consider it, it is nothing.

What is fourteen miles in a tunnel through a mountain?
Some of those on the Great Straightcut Pacific Railroad are forty miles in length, and trains run backward and forward every day without any one considering the danger; and yet there is really more danger from one of those tunnels caving in than in my perpendicular shaft, where caving in is almost impossible.
"As to the danger which attends so great a descent, I have thoroughly provided against that.

In fact, I do not see, if I carry out my plans, how there could be any danger, more than constantly surrounds us, no matter what we are doing.