The conclusions can be characterized as follows: The values of the amplitudes of the diurnal variations of the magnetic field for the vertical component decrease with the diminution of the latitude of the place of observation. This regularity is observed in the middle latitudes of the USSR. Considering the insignificant magnitude of the maximum amplitudes of the diurnal variations of the vertical component of the magnetic field, it is possible not to introduce any corrections for variations in the case of measurement of the vertical component of the magnetic field in the middle latitudes (from 42° to 54° N. L.) of the USSR, if we can confine ourselves to an approximation of ±20 gammes in the results of measurements and verifications. In latitude higher than 54° N it is necessary to take into account the diurnal variations of the magnetic field if we wish to obtain results of measurements and verifications with a precision not under ±40 gammes for the vertical intensity. In cases of measurements of the horizontal intensity it is necessary to introduce corrections depending on variations in observations in every part of the USSR, if we desire to obtain results of measurements and verifications with a precision not under ±40 gammes.