There are two methods of attacking the problem of the elastic properties of the earth, (1) the study of the seismological evidence, on which I shall not touch at all, and (2) the study of earth tides. Even after the best available observational evidence from the earth tides has been obtained, a good deal of hypothesis and interpretation is required before we can say: “The elastic constants of the earth are thus and so.” It is not, however, of this that I wish to speak, but rather of the problem of obtaining the true values of the earth tides. This subject is connected with several other geophysical questions and this paper, therefore, falls naturally into three divisions: (1) Earth tides and the long‐period oceanic tides; (2) earth tides and the short‐period oceanic tides; (3) earth tides and the variation of l