Jed Buchwald
Doris and Henry Dreyfuss Professor of History
Caltech

Throughout most of the 19th century the atom and molecule were not
customary presences in the calculations and laboratories of many physicists.
Although most were convinced of atomic reality, many were not, and in any
case the vast bulk of work in physics had little to do with the micro-world.
All of this had changed dramatically by 1910, for microphysics was by then
at the very foundation of theoretical and experimental research. How did the
micro-world acquire this central role, one that it has played ever since?
Was it propelled to prominence by a series of stunning experimental
discoveries (the electron, X-rays, and radioactivity) that occured between
1895 and 1900? Or did it first emerge on paper, only subsequently acquiring
a new life in such laboratories as the Cavendish? Why did the world of the
atom displace the world of the ether during the 1890s?