It's generally called _aeroline_.

Well, this is forced in, until the specific gravity of the whole affair, passengers and all, is as nearly as possible the same as the specific gravity of the air." "I see.

Good Lord, how simple!" "And the rest is done with planes and screws, driven by electricity.

The tail of the boat is a recent development.
(You'll see it when we're once started.) It's exactly like the tail of a bird, and contracts and expands in every direction.
Then besides that there are two wings, one on each side, and these can be used, if necessary, in case the screws go wrong, as propellers.

But usually they are simply for balancing and gliding.