Article ID: CBB000850601

From Ultrasonic to Frequency Standards: Walter Cady's Discovery of the Sharp Resonance of Crystals (2008)


In 1918--1919 Walter G. Cady was the first to recognize the significant electrical consequences of the fact that piezoelectric crystals resonate at very sharp, precise and stable frequencies. Cady was also the first to suggest the employment of these properties, first as frequency standards and then to control frequencies of electric circuits---an essential component in electronic technology. Cady's discovery originated in the course of research on piezoelectric ultrasonic devices for submarine detection (sonar) during World War I. However, for the discovery Cady had to change his research programme to crystal resonance. This change followed Cady's experimental findings and the scientific curiosity that they raised, and was helped by the termination of the war. Cady's transition was also a move from applied research, aimed at improving a specific technology, to pure research lacking a clear practical aim. This article examines how Cady reached the discovery and his early ideas for its use. It shows that the discovery was not an instantaneous but a gradual achievement. It further suggests that disinterested scientific research (rather than engineering research) was needed in this process, while research aimed at design was required for the subsequent development of technological devices. I am very grateful to Chris McGahey for providing me with his research notes taken from Walter Cady's diaries kept by the Rhode Island Historical Society, henceforth Diaries. I would like to thank Aharon (Arkee) Eviatar for linguistic comments, Ido Yavetz for our helpful discussion and Jed Buchwald for his thoughtful comments and editorial work. I thank the Lemelson Center in the National Museum for American History for a grant that enabled me to study Walter Guyton Cady Papers, 1903--1974, Archives Center, National Museum of American History (henceforth, ACNMAH) and the staff of the center, especially Alison Oswald, for their help. The following abbreviations are used: NB---Cady's research notebooks kept at ACNMAH, AIP - Niels Bohr Library, American Institute of Physics, Cady's dossier.

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Authors & Contributors
Katzir, Shaul
Brady, Tim
Campanile, Benedetta
Fabbricatore, Fabio
Tim Gale
Aleksandŭr Kostov
Technology and Culture
Science in Context
Notes and Records: The Royal Society Journal of the History of Science
Historical Studies in the Physical and Biological Sciences
Historical Studies in the Natural Sciences
Configurations: A Journal of Literature, Science, and Technology
Oxford University Press
Natur & Text
Pavia University Press
Franco Angeli
World War I
Science and war; science and the military
Bragg, William Lawrence
Voigt, Woldemar
Rutherford, Ernest, 1st Baron
Laue, Max von
Langevin, Paul
Einstein, Albert
Time Periods
20th century, early
20th century
19th century
18th century
United States
Great Britain
Red Cross Societies

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