Abstract
To measure velocities of currents automatically, the author has made a recording current meter using a phototube, in which the intermittent, photoelectric current is depicted on a chart of a recorder on deck. The speed and direction of water current can be measured respectively by the time intervals and by the intensity of photoelectric current; Experiments on the sea have shown that by using the current meter, the actual under-water conditions can be immediately observed, and fine, accurate and rapid observations of water current have been made possible.
