Rolling double cone and arms, 1762. If the
© Science Museum / Science & Society Picture Library
Rolling double cone and arms, 1762. If the open ends of the arms are slightly raised and the double cone is placed at the closed end, the double cone appeared to roll uphill towards the open end. The reason for this was that the centre of gravity of the double cone actually dropped as it rolled towards the open end. This was made by George Adams, instrument maker to the king.