the working of some powerful engine
Inevitably, language like this calls to mind the, by now, obligatory
laboratory equipment so characteristic of cinematic versions of the novel.
That is all the more reason, then, for us to recognize that Mary Shelley
is deliberately evoking not mere instrumentation but rather what we would
now call a dynamo to infuse the creature with what she called at the close
of the previous paragraph "vital warmth." Since the first successful
electric generators were demonstrated only in the 1860s, Mary Shelley's
vagueness ("some") reflects her sense that such an engine is a necessary
technological development of current scientific knowledge but has not yet
been invented.
