Figure 23. Current meter invented by Jacob Amsler-Laffon about 1876. This
instrument was devised to measure the currents of streams and rivers. It was an
application of Woltman's electrical turnstile method of measuring the current.
The first use of this instrument was in the Rhine River near Schaffhouse in 1876
. 278 measurements were made at 26 stations at 6 meters depth.