Empirical Transformations from U.T. to E.T. for the Period 1800-1988

Approximation formulae describing the long-term changes in the rotation of the Earth are evaluated. The time scale reduction from Universal to Ephemeris Time can be accomplished by a 12th degree polynomial with a mean error of less than one second for the entire time span 1800 - 1988. The maximum residuals of least squares fits of the 19th and 20th century data, respectively, can be limited to this accuracy be even simpler expressions.