MEMORISLOT RTP SLOT One form of mercury light switch uses a sealed glass vial that is tipped by the toggle lever, causing a drop of liquid metallic mercury to roll from one end to the other, bridging a pair of contacts to complete the circuit. Another style of mercury light switch uses a metal wheel with an insulator separating the two halves that has a hole which allows the mercury to connect either side of the wheel in only one position.|Despite Remaining on the 124-inch Wheelbase