This is a digital reprint of the revised 1976 edition of this classic work. It examines seismology, gravity, the strength of the shell, the variation of latitude and the figure of the Moon.  Meer

A scientific theory is originally based on a particular set of observations. How can it be extended to apply outside this original range of cases? This question, which is fundamental to natural philosophy, is considered in detail in this book, which was originally published in 1931, and first published as this third edition in 1973.  Meer