Made in 1950 in the United Kingdom.
- electromagnetic seismometer for field acquisitions
- the coil is fixed whereas the magnetic field is used as a mobil mass
- used as horizontal or vertical seismometer
- amplificated by potentiometric bridges
- optical recording by means of a galvanometer.
It has been used in France for dams monitoring and especially during big seismic profile acquisitions from the 1960s.