This contraption is a semaphore which was used to indicate wind speed and direction to mariners leaving Bremerhaven. In an age without radio optical telegraphy was a easiest and most reliable means of communication with vessels at sea. Measurements are given for Heligoland (H)and Borkum island (B- the centre and the western approach to the German Bight- the clock-like dials give the direction, the hands on top indicate wind speed ( In this case Heligoland reports winds from North at 4 beaufort). The locals tell clueless tourists an amusing story about this indicating the prices for Kippers (Bückling in German) and herring