Excerpt from The Principles of Science: A Treatise on Logic and Scientific Method It is hardly needful to point out too that on the earth's surface we live under nearly uniform conditions of gravity, temperature, and atmospheric pressure, so that if we are to extend our inferences to other parts of the universe where conditions may be widely different, we must be prepared to imitate those conditions on a small scale here. We must have intensely high and low temperatures we must vary the density of gases from approximate vacuum up wards we must subject liquids and solids to pressures or strains of almost unlimited amount. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.