How far is the ship from land when Walton sees the gigantic figure in the dogsled.(Frankenstein by Mary Shelly)

Walton believes they are hundreds of miles from land when they observe the dogsled.

This appearance excited our unqualified wonder. We were, as we believed, many hundred miles from any land; but this apparition seemed to denote that it was not, in reality, so distant as we had supposed. Shut in, however, by ice, it was impossible to follow his track, which we had observed with the greatest attention.