1. A SWITCH COMPRISING A HOLLOW BODY, PLATE MEANS SEALING THE TOP OF THE HOLLOW OF SAID BODY, THE HOLLOW OF SAID BODY HAVING A SIDEWALL, A SPLIT CONE ELECTRODE MEANS INCLUDING TWO ELECTRICALLY-CONDUCTIVE ELEMENTS SUPPORTED IN THE HOLLOW OF SAID BODY BENEATH SAID PLATE, SAID ELEMENTS BEING SPACED A SMALL DISTANCE APART, MEANS FOR SEALING THE BOTTOM OF SAID HOLLOW INCLUDING A PISTON ARRANGED AT THE BOTTOM OF SAID HOLLOW BODY, SAID PISTON HAVING LIMITED AXIAL MOVEMENT IN THE HOLLOW OF SAID BODY, A SMALL BODY OF MERCURY NORMALLY RESTING ON SAID PISTON MEANS BENEATH SAID PLATE, AND DEFLECTOR MEANS ADJACENT SAID ELECTRODE MEANS FOR DEFLECTING MERCURY WHICH STRIKES THE SAME SUBSTANTIALLY AXIALLY OF SAID BODY IN THE DIRECTION TOWARD SAID ELECTRODE MEANS, WHEREBY WHEN A SUDDEN FORCE IS APPLIED AT THE BOTTOM OF SAID HOLLOW BODY SAID PISTON MEANS IS SUDDENLY RAISED TO THROW SAID MERCURY UPWARD WHERE IT IS DEFLECTED TO PASS BETWEEN SAID TWO ELEMENTS AND MOMENTARILY COMPLETE A CIRCUIT THROUGH SAID ELECTRODE MEANS.