Walfrid Ekman (WE) was during ICES first years 1902-8 employed at its Central Laboratory (CL) in Norway. He was in this period very active in writing theoretical articles , as well as constructing instruments. In 1905 he described a propeller current meter (CM), where small balls, directed by a compass, fall into compartments.

When ICES in 1908 closed its CL, WE returned to Sweden where he was appointed Professor of Theoretical Physics at the University of Lund. During his Norway years he had met Björn Helland- Hansen (HH) then working in Bergen/Norway. The two families met and many letters were exchanged. The contact was then nearly none before 1919, from when it grew more and more up to WEs death in 1954. Common oceanographic cruises on Norwegian ‘Armauer Hansen’ were carried out. In 1924 HH tested WEs Repeating CM at sea with good results. Sverdrup at al. (1942) describes it shortly:

“In this instrument (WE 1926) the propeller is released and stopped by messingers. When the propeller is stopped, three numbered balls are released from a container. One ball drops down into a compass box, giving the direction of the current at the time the propeller was stopped, and two balls are guided into other slots by the position of dials turned by the propeller. From the slots into which the balls fall, the positions of the dials can be found and thus the number of revolutions of the propeller can be obtained. The messengers are designed to split when they strike the instrument, and the two parts are caught in a container. The operation can be repeated forty-seven times, when the store of numbered balls is exhausted.”

I’ll give a Power Point Presentation including most of the figures of WE (1926) in demonstrating this CM. A map of the sea area west of Gibraltar will show the sites of June-August 1930 current measurements at stations A-F, deepest at E of nearly 4.000 meters and longest at D of 141 hours.