Michelson and Morley's 1887 ether-drift apparatus

This project sought to deliver new perspectives on the material, conceptual, and disciplinary foundations of physics in the period from 1870 to the 1920s. A primary focus (and the subject of a book manuscript) was a new account of the multiple lines of investigation—theoretical, experimental, and instrumental—which coalesced, diverged, and intersected anew to produce not only the history of relativity we currently recognize, but a more complex, contingent, and involved story with a cast of unfamiliar characters and new themes. Why did Michelson and Morley never complete the ether-drift experiment as planned in 1887? How was the history of the screw relevant to the analysis of space and time in 1905? Who invented “classical” physics?

There were several important methodological underpinnings to the project. The first was to follow the multiple threads of many actors with different trajectories and interests, as they work overlapping but not parallel lines of investigation. This meant exploring the research concerns of the originator of the ether-drift experiment, and what he made of his experiment—a new instrument—rather than inquiring solely about crucial experiments or the use theorists made of the Michelson-Morley experiment. It meant investigating the material culture of measuring space and time, in experimentalists’ work to track the motion of electrons on minute photographic plates in 1905. It means exploring the formulation of concepts of "classical physics” in the work of a host of theorists after the arrival of Planck’s quanta and Einstein’s relativity in 1900 and 1905.

But if theorists, experimentalists, and instrumentalists pursue open-ended, intersecting, but often divergent lines of investigation, how do they form coherent and stable knowledge, decisive experiments, and robust instruments? A further methodological underpinning is a close study of the various strategies used to create coherence amidst and across the diverse realms of theoretical and experimental physics.


Detail of Michelson's 1893 apparatus to determine the length of the metre in terms of the wavelength of light.

Institutionally Richard Staley explored two different conferences that offered very different insights into the physics discipline: the broad and inclusive but now largely forgotten Inaugural International Congress of Physicists that was held in conjunction with the Paris World Fair in 1900; and the small, elite, and still iconic first Solvay Congress of 1911. Intellectually he focused particular attention on an important means for conveying the meaning and implications of new research beyond the realm of its initial development: physicists’ research histories. Investigating the constructive role of participant histories that integrate current research with past physics, the project established significant links between the detailed work involved in achieving a common interpretation of a single set of equations and physicists’ maneuvers on the broader stage of international disciplinary politics. Probing the importance of particular understandings of the past for the formation of a new physics enables us to trace the complex process by which relativity came to be proclaimed “a Copernican revolution,” just five years after Einstein’ s 1905 paper; and to explain for the first time when and why relativity and quantum theory came to be described as overthrowing “ classical physics.”

Related research has involved a study of the meteorological tradition in Cambridge that informed C.T.R. Wilson’ s development of the cloud chamber in 1895, and an exploration of the nature of experimental work on “natural standards.” Empirical work in the late nineteenth century—often configured around the idea of developing standards—prepared the grounds for the subsequent articulation of a vision of physics based on principles and constants by the people who became the key theorists, Planck, Poincaré, and Einstein. Rather than seeking the sources of modern physics in theoretical change alone, this project would provide a way of exploring its development as an outgrowth of the concerns of experimentalists also. One facet of this work, in collaboration with Otto Sibum, was a historical contextualization of the concepts of repetition, (re)determination, and replication, which are key to understanding the economy of experimental performance that shaped physicists choices of research projects.