Earth's Rotation from Eons to Days reviews long-term changes, methods of measurement, and the major influences on rotation parameters. In order to understand secular changes, the momentary behavior of ocean tides must be analyzed and appropriately modelled. Researchers and students in astronomy and all fields of geosciences will find a wealth of information related to the interaction of geophysical phenomena and the rotation of the planet Earth.

In the four years which elapsed between our first workshop on .Tidal Friction and the Earth's Rotation and the second, the proceedings of which are presented here, many of the disciplines involved made ad vances which we felt should be exchanged. We were encouraged by the good reception our first report met with. Of course, more insight often means more problems. Therefore, this volume contains new results and revisions of matters which previously appeared settled. We are certainly far from "final answers". For this reason, differing opinions on some issues are to be found in this book. Moreover, we have refrained from making mathematical symbols uniform to avoid the risk of errors and non-compatibility with the earlier work of an author. The two workshops have stimulated collaboration between participants working in various fields. The final versions of the contributions have already profited from these discussions. We are convinced that they will also influence further investigations. This advancement of our past and future aims is based on the very existence of the Centre for Interdisciplinary Studies and on the support we have received from its leading members. The authors have agreed to dedicate this book to Dr. H. Gerstenkorn, who died in 1981. He contributed fundamental ideas to the scientific fields treated in the meeting. P. Brosche Daun, September 1982 J. Slindermann Contents * Julius Robert Mayer's Ideas on a Theory of Tidal Friction H.P. Miinzenmayer ...***.***..**.*..*...**..*...*.***.****....*..

P.Brosche The development of the ideas and observational techniques related to the subject of our meeting "Tidal friction and the Earth's rotation," Bielefeld, September 1977 is one of the most fascinating books - not merely chapters - of the modern history of science. Its genealogical tree is as intricate as that of mankind itself: There are dead ends and superfluous re-discoveries. Due to these circumstances and to the pure extent of the topic, it is impossible to give more than a few highlights here. The first relevant observational fact was discovered by the famous English astronomer E. Halley in 1695 (Berry, 1961). He simply could not arrive at an agreement between ancient and recent eclipses using a constant mean angular motion of the Moon. Instead, he had to intro duce an empirical acceleration term in the mean motion. Known as the "secular acceleration," it has ever since been a most challenging sub ject of celestial mechanics and a main branch of the genealogical tree already mentioned. In 1754, completely independently and almost certainly in ignorance of those specialists' activities, the German philosopher Kant established the idea of tidal friction as a decelerating mechanism for the rotation of the Earth (Felber, 1974). Although he made some errors in his rough computations, the majority of the constitutive elements of his concept have survived to the present day (Brosche, 1977)."