For more info about the number of seconds in a solar day, I would rather recommend the table at http://en.wikipedia.org/wiki/Solar_time#Apparent_solar_time http

For more info about the number of seconds in a solar day, I would rather recommend the table at http://en.wikipedia.org/wiki/Solar_time#Apparent_solar_time http://en.wikipedia.org/wiki/Solar_time#Apparent_solar_time . The Leap_second article discusses a much smaller variation (~2 ms) on top of the big cyclic variation (~20 s).