pl23_ship4043.jpg
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https://www.noaa.gov/media/digital-library-photo/pl23ship4043jpgDescription
Figure 38. Percussion current meter invented by Julien Thoulet. Top: Number99 0610. Bottom: Number 99 0611. When the helix turned it caused a striker to fall on a steel plate. The sound of this was recorded by a hydrophone and thenumber of recorded sounds per unit time was directly related to current strength. This was tested off Monaco by Dr. Jules Richard in 1921.
Credit
Oceanographic Museum of Monaco
Photographer
P. Roggero
Category
Voyage to Inner Space
History of Oceanography Collection
The Early Instruments - Collections of the Oceanographic Museum at Monaco
Current Measuring Devices
Keywords
Oceanography
Historical instruments