The Replication of Hertz:s Cathode Ray Experiments

I reappraise in detail Hertz's cathode ray experiments. I show that, contrary to Buchwald's (1995) evaluation, the core experiment establishing the electrostatic properties of the rays was successfully replicated by Perrin (probably) and Thomson (certainly). Buchwald's discussion of &current puri"cation' is shown to be a red herring. My investigation of the origin of Buchwald's misinterpretation of this episode reveals that he was led astray by a focus on what Hertz &could do'*his experimental resources. I argue that one should focus instead on what Hertz wanted to achieve*his experimental goals. Focusing on these goals, I "nd that his explicit and implicit requirements for a successful investigation of the rays' properties are met by Perrin and Thomson. Thus, even by Hertz's standards, they did indeed replicate his experiment. ( 2001 Elsevier Science Ltd. All rights reserved.