This suggests that Walton implicitly recognizes the third element, after electricity
and magnetism, in what would in the twentieth century be called a "grand unified field
theory," gravitation.
That a unified field theorem is a still unrealized ideal of experimental physics,
one that has excited the ambitions of major scientific minds in all quarters of the
world, may indicate the seriousness of the scientific issues and passions underlying
Mary Shelley's novel. Without denigrating those ambitions here, she characteristically
reminds us of human limitations in Walton's inability to recognize that in a land
of eternal light, as he imagines the pole might be, celestial observations would be
impossible.