Figure 69. Langevin quartz ultrasonic projector. This device was built in 1925 by the Society for Condensation and Mechanical Applications based on work byPaul Langevin. It was also distributed by the Marconi Company. It consisted of a piezo-elec
4/4/2019 2:12:27 PM
Photographer: Y. Berard
Credit: Oceanographic Museum of Monaco
Subject: Oceanography
Subject: Historical instruments