For I was not prepared to see Father Mapple after gaining the height, slowly turn round, and stooping over the pulpit, deliberately drag up the ladder step by step, till the whole was deposited within, leaving him impregnable in his little Quebec.
Some weeks after, the Commodore set sail in this impregnable craft for Valparaiso.
Finally, though, as will soon be revealed, its contents partly comprise the most delicate oil; yet, you are now to be apprised of the nature of the substance which so impregnably invests all that apparent effeminacy.
Furthermore: concerning these last mentioned Leviathans, they have two firm fortresses, which, in all human probability, will for ever remain impregnable.
Unerringly impelling this dead, impregnable, uninjurable wall, and this most buoyant thing within; there swims behind it all a mass of tremendous life, only to be adequately estimated as piled wood is—by the cord; and all obedient to one volition, as the smallest insect.
There are no more uses of "impregnable" in the book.