Chapter

1 1 |   myself wrestling with so many impenetrable mysteries.~In the remarkable
2 1 | invisible.~In the midst of this impenetrable obscurity, there was no
3 3 |        that their thickets were impenetrable.~We arrived that evening
4 3 |        right, as to left, arose impenetrable masses of trees and bushes.
5 14|         but could he pierce the impenetrable fortress of the Eyrie? No!
6 16|        a threat, within his own impenetrable fortress!~Let me recall
7 17|       Robur the Conqueror. This impenetrable hiding-place where he stored