Apparatus for making seismic surveys

Claim 1

A SYSTEM FOR RECORDING THE TIME INTERVAL BETWEEN TWO EVENTS CLOSELY CONNECTED IN POINT OF TIME, ONE OF WHICH EVENTS IS THE OPERATION OF A DEVICE FOR PRODUCING SEISMIC VIBRATIONS AND THE OTHER OF WHICH EVENTS IS THE RECEPTION OF SAID VIBRATIONS AT A DEVICE FOR DETECTING SEISMIC VIBRATIONS, TRANSFORMER MEANS HAVING AT LEAST ONE PRIMARY WINDING, TWO SECONDARY WINDINGS, AND TWO OPPOSITELY WOUND INDEPENDENT SATURATION CONTROL WINDINGS, SAID PRIMARY WINDING BEING CONNECTED TO A SOURCE OF ALTERNATING POTENTIAL, SAID SECONDARY WINDINGS BEING CONNECTED IN PHASE OPPOSITION AND TO AN OUTPUT MEANS, A FIRST INPUT MEANS CONNECTED TO ONE OF SAID SATURATION CONTROL WINDINGS AND A SECOND INPUT MEANS CONNECTED TO THE OTHER OF SAID SATURATION CONTROL WINDINGS WHEREBY THE FIRST OF SAID SATURATION CONTROL WINDINGS SATURATES SAID TRANSFORMER MEANS UPON THE OCCURRENCE OF ONE OF SAID EVENTS AND THE OTHER OF SAID SATURATION CONTROL WINDINGS CANCELS THE SATURATED CONDITION OF SAID TRANSFORMER MEANS UPON THE OCCURRENCE OF THE OTHER OF SAID EVENTS, SAID OUTPUT BEING CONNECTED TO A MARKING MEANS, ONE OF SAID INPUT MEANS BEING CONNECTED TO SAID DEVICE FOR PRODUCING SEISMIC VIBRATIONS, AND THE OTHER OF SAID INPUT MEANS BEING CONNECTED TO SAID DEVICE FOR DETECTING SAID SEISMIC VIBRATIONS.