Anemometer

The location is at the eastern end of Euston Square. The camera faces south east. In the foreground there are trees, in the middle distance the Euston Road, (a junction with traffic lights), the camera and the anemometer were set on tripods within a few feet of each other. The camera angle did not change during the shooting but the filming speed varied according to the wind speed. (See anemometer circuit diagram circuit diagram and specifications).
Once it was connected to the power supply and switched on the camera was not interfered with in any way until all of the film was used up.