A double anxiety now possessed all on board the _Susquehanna_: the prisoners in the Nautilus were in danger as well as the prisoners in the Projectile.

Marston and his friends, however, were anything but disquieted on their own account, and, pencil in hand and noses flattened on the glass plates, they examined carefully everything they could see in the liquid masses through which they were descending.
For the first five hundred feet, the descent was accomplished with little trouble.

The Nautilus sank rather slowly, at a uniform rate of a foot to the second.

It had not been two minutes under water when the light of day completely disappeared.

But for this the occupants were fully prepared, having provided themselves with powerful lamps, whose brilliant light, radiating from polished reflectors, gave them an opportunity of seeing clearly around it for a distance of eight or ten feet in all directions.