Kaufmann’s device was not very big.  This would actually turn out to be the source of some observational problems with the small curves on the photographic emulsions he used to detect the effects of electromagnetic fields on speeding beta-ray electrons rocketing out of a chunk of Radium.  And, of course, as Freud (who was a very busy man in the first decade of the 20th century) might well have observed for himself firsthand, “Sometimes a vacuum tube thing is just a vacuum tube thing.”  The critical spots of emulsion were smaller than a postage stamp being hit by beta-rays going about 80% of the speed of light after a quick twisty trip through a near vacuum clear of all but the finest traces of the fast-fading aether.

Interestingly, with Kaufmann’s work, we enter the realm of abundant and accessible documentation.  Wikisource has some of Kaufmann’s papers in English and at least one paper of Searle’s – the one in fact from which Kaufmann derived his formula for the field energy of a rapidly moving electron.

As always, it is worth noting the Hathi Trust Digital Library has an enormous number of books scanned as texts and PDFs  There you can find Drude 1900 in the 1902 translation, Max Born’s book on relativity and notes from the first class Dyson gave on Quantum Electrodynamics — the riches there are pretty indescribable but the huge number of entries can make searching pretty tedious.  With Kaufmann’s work and its context, things are different, probably due to the fact that Kaufmann is associated with the emergence, early testing and gradual acceptance of Special Relativity.  The association with relativity and the early electron models have their own interest, as Janssen and Mecklenburg note in their masterly and comprehensive work on early electron models – which is to say – Janssen, Michel and Matthew Mecklenburg, “Electromagnetic Models of the Electron and the Transition from Classical to Relativistic Mechanics”, a Preprint from 2004 issued in PDF format by the Max Planck Institute for the History of Science.  Janssen and Mecklenburg themselves note “A voluminous literature on the various aspects of this story.”  They cite many of our sources seen so far in this blog (Pais on Einstein, Miller on Einstein and Feynman’s Lectures Vol II Chapter 28 on electromagnetic problems).  Janssen and Mecklenburg emphasize Max von Laue’s work in 1911 showing that the electron’s stability and Minkowski Space and Special Relativity when combined provided a consistent picture of the interaction of electromagnetic fields and moving electrons.  They suggest that winding up the story of the failed electromagnetic revolution with von Laue’s description of the relativistic electron in Minkowski Space is a neglected, but worthwhile, narrative end game.  At the moment, I’m not so sure.  The situation in 1911 does seem to spell the end of the dream of an electromagnetic universe – at least for a core group of physicists.  Miller notes on page 257 of Albert Einstein’s Special Theory of Relativity that, in 1911, Sommerfeld declared that special relativity was so well established that it was no longer on the frontiers of physics, which may have been true for the physicists who were going to go on to make progress in the fundamental areas of particle physics, from electrons to nuclear models and mesons, but not so much for other areas of science and not so much for people like Lorentz and Larmor who could not quite let go of the aether or people like Stark and Leonard who came to oppose relativistic theory out of the same generalized cultural disturbance that produced Fascism.

To add some variety to the exposition of Kaufmann’s work here, I will also be using Giora Hon’s “Is the Identification of Experimental Error Contextually Dependent?  The Case of Kaufmann’s Experiment and its Varied Reception” in Buchwald’s Scientific Practice.