This one, the diameter of which is nineteen feet, and the thread twenty-three feet, performs about 120 revolutions in a second." "And you get then ?" "A speed of fifty miles an hour." "I have seen the Nautilus manoeuvre before the Abraham Lincoln, and I have my own ideas as to its speed.

But this is not enough.

We must see where we go.

We must be able to direct it to the right, to the left, above, below.

How do you get to the great depths, where you find an increasing resistance, which is rated by hundreds of atmospheres?
How do you return to the surface of the ocean?
And how do you maintain yourselves in the requisite medium?
Am I asking too much ?" "Not at all, Professor," replied the Captain, with some hesitation; "since you may never leave this submarine boat.