In this brief essay Kant throws out a notion which has since been carried out, in ignorance of Kant's priority, by Delaunay(1865) and Adams. He points out that the action of the moon in raising the waters of the earth must have a secondary effect in the slight retardation of the earth's motion, and refers to a similar cause the fact that the moon turns always the same face to the earth.
Hansen, Fundamenta nova investigationis orbitae verae quam luna perlustrat (Gotha, 1838); Darlegung der theoretischen Berechnung der in den Mondtafeln angewandten Storungen (Leipzig, 1862); C. Delaunay, Theorie du mouvement de la lune (2 vols., Paris, 1860-1867); F.
Delaunay, developed in his Theorie du mouvement de la lune (2 vols., 1860, 1867), because it contains a germ which may yet develop into the great desideratum of a general method in celestial mechanics.
It was found on comparing the results of Hansen and Delaunay that there are some outstanding discrepancies which are of sufficient magnitude to demand the attention of those interested in the mathematical theory of the subject.
This diminution was soon fully confirmed by others, especially Delaunay, although for some time Pontecoulant stoutly maintained the correctness of the older result.