BLONDEL, (ANDRE É.). - THE INVENTION OF THE ELECTROMAGNETIC OSCILLOGRAPH.

Oscillographes; nouveau appareils pour l'étude des oscillations électriques lentes.

(Paris, Gauthier-Villars), 1893. 4to. No wrappers. In: "Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences", Tome 116, No 10. Pp. (453-) 542 (entire issue offered). Blondel's paper: pp. 502-506 a. textillustration.

First printing of the paper in which Blondel describes his invention of the electromagnetic oscillograph, a device that allowed electrical researchers to observe the intensity of alternating currents.
The bifilar and soft iron oscillographs won the grand prize at the St. Louis Exposition in 1904. They were more powerful than the classical stroboscope, invented in 1891 then in use. They remained the best way to record high-speed electrical phenomena for more than 40 years when they were replaced by the cathode ray oscilloscope. They paved the way for a greater understanding of the behavior of alternating current.

Order-nr.: 49886