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NOAA Photo Library Image - ship4043

Figure 38. Percussion current meter invented by Julien Thoulet. Top: Number 99 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 the number of recorded sounds per unit time was directly related to current strength . This was tested off Monaco by Dr. Jules Richard in 1921.

Image ID: ship4043, Voyage To Inner Space - Exploring the Seas With NOAA Collect
Photographer: P. Roggero
Credit: Oceanographic Museum of Monaco

Category: Oceanography/Historical instruments/

High Resolution Photo Available

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Last Updated:
November 10, 2017