Volney Mathison, an early Dianeticist who, after listening to a lecture by L. Ron Hubbard outlining the equipment and circuits necessary to detect mental charge, built the first E-Meter in 1951, the Model B. There were various other models of E-Meters built by Mathison which were used by auditors. The E-Series in 1954 was his lastmodel as his meters had become too complex to be workable. —3rd South African published appr gls (14.4.92)