Harvey Fletchers Untersuchungen zur Brown'schen Molekularbewegung

The project focuses on Harvey Fletcher, who participated in the research of his Ph.D. supervisor Robert A. Millikan in Chicago from 1909 to 1911 and independently continued this research in Provo, Utah. The study sheds light on the realization and development of a central experiment in the history of the atomic debate. Experimental practice involving several objects of investigation - the determination of the elementary charge and the thermal motion of particles - within a laboratory with many physicists using a single instrumental setup raises several questions: What mechanisms do researchers use to stabilise an experiment across diverse research questions? How does recording experimental data adapt when used to analyse different theories? And how do individuals with different approaches and skills collaborate in a laboratory, shaping the collective experimental practice?

To answer these questions, I analyse the publications of the Ryerson Laboratory in Chicago and the existing laboratory books and letters of the employees from 1908 to 1920. Additionally, the papers of Harvey Fletcher in Provo will be explored in this context for the first time. The project will also consider the material components by including and reflecting on a replica of one of the oil drop apparatuses, which is particularly relevant to the study of experimental practice.

The analysis improves our understanding of how apparatus and experiments in physics enable research on different topics simultaneously. Furthermore, it shows us how collaboration characterises and enables research practice in the laboratory, broadening our understanding of the complex realities of scientific research.