The purpose of this part of IEC 60404 is to define the method of measurement of the magnetic flux density@ magnetic polarization and the magnetic field strength and also to determine the demagnetization curve and recoil line of permanent magnet materials@ such as those specified in lEC 60404-8-1 [1] 1@ the properties of which are presumed homogeneous throughout their volume. The performance of a magnetic system is not only dependent on the properties of the permanent magnet material but also on the dimensions of the system@ the air-gap and other elements of the magnetic circuit. The methods described in this part of IEC 60404 refer to the measurement of the magnetic properties in a closed magnetic circuit. 1 Numbers in square brackets refer to the Bibliography.