Written by Mary Somerville
A Preliminary Dissertation on the Mechanisms of the Heavens
by Mary SomervillePhysical astronomy is the science which compares and identifies the laws of motion observed on earth with the motions that take place in the heavens, and which traces, by an uninterrupted chain of deduction from the great principle that governs the universe, the revolutions and rotations of the planets, and the oscillations of the fluids at their s..