When I placed the south end of a magnet on the right hand side of the green CRO spot (when timebase is off) facing towards the left hand side of the screen, I expected the spot to move downwards in accordance with the left hand rule, but instead it moves upwards. The spot also moves down when I hold the same magnet on the left hand side with south facing to the right, when it ought to go up. I have checked the magnet and the pole is definitely south, and I have also tested other magnets and get the same result. By the left hand rule in the first case above, the field is left to right across the screen into the south pole of the magnet. The current is into the screen, opposite the flow of electrons in the beam towards the screen, so the force ought to be down. Can anyone explain what might be happening?