The aim of this work is comparative study the long term variation in third and fourth harmonics of daily variation of cosmic intensity on sixty quietest days in a year using the data of equatorial and mid – latitude neutron monitoring stations have been investigated for studying comparative variation in third harmonic of cosmic ray intensity during solar cycle twenty one and twenty two. It has been observed that in spite of the abrupt changes in the amplitude and phase of the tri-diurnal anisotropy in cosmic ray intensity, the amplitude of third harmonic is observed relatively larger during the declining phase of solar cycle twenty one and twenty two as it is observed during the declining phase of solar cycle twenty at equatorial stations. Further ,the amplitude of third harmonics of daily variation on quiet days in significantly low value during the 1981 and 1990 at mid-latitude stations. Furthermore the phase in third harmonics shift to earlier over during the period 1990-91 showing the dependence on the polarity of solar magnetic filed, which is attributed to drift effect at mid – latitude neutron monitoring stations.