The nodal corrections are effective for K1; O1 and K2. The components Q1, J1, OO1 and NO1(M1) are stabilized at sites where the tide is predominantly linear and where third order effects are minimal. The effectiveness of the corrections for Nu2 and Mu2 is not apparent but this fact has little practical importance. It is not prudent to apply any a priori corrections to 2N2, N2 and L2. S2 may at times be modulated by its non linear interaction with M2. P1 could theoretically be modulated by its interaction with K1 but no example of this occurrence could be found. The component M2, which usually is the major component, exhibits much variability; it may be demodulated by the nodal corrections when the local tide is linear. The amplitude corrections for M2 become excessive when non linear effects become preponderant although the phase corrections continue to help.