The gizmo in question is a
Crookes Radiometer but they are also known as solar radiometers and light mills. Neither of these latter names is technically correct as the movement comes as a result of heat not light, but there is still much conjectur as to exactly which train of forces cause the movement.
I remember playing with one of these at school a lot - they have a partial vacuum inside the bulb, the vanes will not rotate under full air pressure, nor under a strong vacuum.
They are still a hell of a lot fun to play with!
