One of our members donated this device to Explorer. It consists of a frame attached to a Venturi containing an impeller connected to two worm drives. The worm drive is attached what presumably was a recording device. A bourdon tube is attached for reasons yet to be gleaned. It seems to have a depth limit of 210m inscribed and looks like it might have been an instrument to measure sub sea currents. I’m betting John Dunn will know.
And of course he does.
This is a Currie Foxton depth /flowmeter. It used smoked glass cylinders which the stylus attached to the bourdon tube scratched out how deep a plankton net had been on a tow. The impeller turned a series of clockwork type dials and gave you a rough idea how much water had been filtered by the plankton net. I used to melt Vaseline in very hot water which the clean glass tubes were dipped in and allowed to cool. Then special smokey candles were used to smoke the glass cylinders and they were stored on wooden trays which wooden pegs of the correct diameter. The stylus is missing of this model as is the clockwork gauges!
Ze next question Meester Dunn maybe be a leetle treekier.