The original data used by Daodson as he worked out the development were taken from Brown and Newcomb; the value of the obliquity of the ecliptic is the value on January 1. 1900. i.e. e = 23°27'08. 26. At present, Brown's coefficients have already been recalculated; the obliquity of the ecliptic have relative changes of 5×10-4 per century and 25×10-4 per century in the eccentricity of the earth orbit. The secular trends due to those are discernible in the tidal amplitudes. This is the time dependency of tida...