GEOPHYSICAL INSTRUMENTS - NAMELY, MAGNETOMETERS, GRAVIMETERS, RESISTIVITY AND INDUCED POLARIZATION APPARATUS, ELECTROMAGNETIC AND VERY LOW FREQUENCY INSTRUMENTS, SEISMOGRAPHS, BOREHOLE LOGGING AND DEVIATION APPARATUS, AND GROUP RADAR UNITS
GEOPHYSICAL INSTRUMENTS - NAMELY, MAGNETOMETERS, GRAVIMETERS, RESISTIVITY AND INDUCED POLARIZATION APPARATUS, ELECTROMAGNETIC AND VERY LOW FREQUENCY INSTRUMENTS, SEISMOGRAPHS, BOREHOLE LOGGING AND DEVIATION APPARATUS, AND GROUP RADAR UNITS