Interesting post, especially in the context of the Enlightenment thinking in which Mary Shelley was schooled, formally and informally (her anarchist philosopher father's house serving sometimes as a salon for London's radical intellectuals). In the context of a Regency-period political culture already jittery about goings-on across the Channel (the continuing fallout of the French Revolution) and inclined to censorship and suppression of radical discourse, Mary Shelley's imagery is maybe even more charged (pardon the electrica pun) with significance and ambiguity. Enlightenment thinking did in several ways pose destabilizing danger to the status quo and powers-that-were of the age. Enlightenment philosophy, harbouring a new valuation of democracy, rights, and secular values (which also entailed a critical rethink of monarchy as absolute, meaning divinely conferred, power), had driven the French Revolution and the English ruling elite's fear was that it would mean anarchy in the UK too.

So the fact that Shelley here investigates the positive, negative, and ambiguous charges and valences of the imagery of light evinces both a familiarity with Enlightenment thought -- and a suspicious wariness of it and its applications (when specifically wielded by overzealous men who also play fast and loose with research ethics...)