8 ENGLISH MEN OF SCIENCE. [CHAP.
tions of Darwin. In spectrum analysis the remarks of Stokes were anterior to and independent of the works of Kirchhoff and Bunsen. Electric telegraphy has numerous parents, German, English and American. The idea of conservation of energy has unnumbered roots. The simultaneous discovery of the planet Neptune on theoretical grounds by Leverrier and Adams is a very curious instance of what we are considering. In patent inventions the fact of simultaneous discovery is notoriously frequent. It would therefore appear that few discoveries are wholly clue to a single man, but rather that vague and imperfect ideas, which float in conversation and literature, must grow, gather, and develop, until some more perspicacious and prompt niincl than the rest clearly
sees them. Thus, Laplace is understood to
have seized on Kant's nebular hypothesis and
Bentham on Priestley's phrase, " the greatest
happiness of the greatest number," and each
of them elaborated the idea he had so seized,
into a system.
The first discoverers beat their contemporaries