The Leyden jar is widely recognized as among the most important discoveries in the history of electricity. First described in 1745 by the Pomeranian Cleric Ewald von Kleist and independently reported by the Dutch professor Pieter van Musschenbroek in early 1746, the device was simple but surprising. By charging a glass of water in hand, the experimenters found, they were able to produce sparks far more powerful than anything they had seen before, ones capable of lighting cotton on fire and doubling over anyone brave or foolish enough to lose the blow upon themselves. Within a year, jars could be found in every laboratory in Europe; within five, more papers had been published in electricity than in any twenty-year period before. Most famously, the case is cited by Thomas Kuhn in Structure as an example of an anomaly leading to a scientific revolution.
Traditionally, these events have been presented as a mix of luck and crisis. The discovery itself is said to have resulted from an accident, and its momentous reception is typically discussed in terms of the challenges it posed to existing effluvial theories of electricity. Examining the details of the case, however, a different picture emerges. Although the discovery was not anticipated, it can be seen as a natural product of an exploratory research strategy commonly adopted by electricians at the time, not simply a fortuitous accident. On the import of theory, one finds that theoretical discussions, while not absent, were far less central than the standard narrative would lead one to believe. The common electrician seems to have been at least as concerned with their ability to control the relevant phenomena (in this case electricity) and the various practical and amusing applications of their discoveries as they were with their impact on theory. Reviewing the case, it seems clear that the electricians succeeded not despite their approach but in part because of it. The discovery was indeed revolutionary but for reasons quite different from what has long been assumed.
Research Highlights: The Leyden Jar
A summary of the results from our case study on the discovery and impact of the Leyden jar.
This research highlights document includes background on how the Leyden jar works followed by some of the principal arguments and conclusions of the research. The highlights include references to relevant passages of the case study and external sources further detail.
Translations of Unpublished Kleist Letters
In this document, we share three previously unpublished letters from Kleist detailing his early studies, along with English translations. The originals are available in the Biblioteka Politechniki Gdańskiej written in Kurrent, a cursive script common in German-speaking countries at the time. To our knowledge, the letters have not been used in English language histories. We hope sharing them will contribute to further research in the area. Thanks and credit to Helen Hunter for the transcriptions.