Abstract: A target identification system for detecting a desired ferrous object concealed beneath a surface is provided for a gradiometer. The system has first and second sensors for detecting a magnetic field at a first and second points above the surface. A device for providing drive signals for the sensors is connected to the sensors, to generate sensor output signals proportional to the magnetic fields sensed by the sensors. The outputs of the sensors are connected to means for generating a difference signal at an output thereof, the difference signal being the difference between the output signals of the sensors and being proportional to the detected gradient of the magnetic field between the first and second points. An interface receives the difference signal for producing an indication signal when said magnetic field has a selected polarity and when the magnitude of the detected magnetic field gradient exceeds a set value.

Abstract: A cage lure for attachment to a fishing hook and a fishing line, and for containing bait is disclosed. The cage lure comprises a bait enclosure bag having a flexible meshed construction; a dual spring closure means for closing the open end of the bait enclosure bag; a leader having openable attachment rings, the rings adapted for attachment, in use, to the fishing line and the fishing hook; and means for releasably attaching the bait enclosure bag to the leader, the attachment means comprising at least two loops.