Conceptions of science, then and now: how many movies feature a mad scientist as one of protagonists? It was a theme as popular in the 19th century as it is today; its interesting to see how the character has evolved with time.
The modern mad scientist -- a figure typified by Dr. Strangelove -- is hyper-rational. He thinks and speaks in a jargon which, although technical, conveys precision and accuracy; he makes no secret of his disdain for the non-scientists he interacts with; he is slightly eccentric, peculiar, the kid who never fit in back in his school days.
By contrast, the mad scientist of the 19th century was a figure steeped in magic. He spoke in a language reminscent of the medieval mystics, using words that were readily understandable but in new and unexpected ways. Everything about him seemed slightly supernatural; and the schemes he proposed sound like enchantments to modern ears. Shelley's Frankenstein is one book that does not fit this trend, but consider how Hawthore describes the laboratory of a such a character in Dr. Heidegger's Experiment:
It was a dim, old-fashioned chamber, festooned with cobwebs, and besprinkled with antique dust... Over the central bookcase was a bronze bust of Hippocrates, with which, according to some authorities, Dr. Heidegger was accustomed to hold consultations in all difficult cases of his practice. In the obscurest corner of the room stood a tall and narrow oaken closet, with its door ajar, within which doubtfully appeared a skeleton. Between two of the bookcases hung a looking-glass, presenting its high and dusty plate within a tarnished gilt frame. Among many wonderful stories related of this mirror, it was fabled that the spirits of all the doctor's deceased patients dwelt within its verge, and would stare him in the face whenever he looked thitherward... The greatest curiosity of the study remains to be mentioned; it was a ponderous folio volume, bound in black leather, with massive silver clasps. There were no letters on the back, and nobody could tell the title of the book. But it was well known to be a book of magic; and once, when a chambermaid had lifted it, merely to brush away the dust, the skeleton had rattled in its closet, the picture of the young lady had stepped one foot upon the floor, and several ghastly faces had peeped forth from the mirror; while the brazen head of Hippocrates frowned, and said,--"Forbear!"