Excerpt from A Text-Book of Physics It will be seen as we proceed that in some parts of the subject the relations between Observed facts are better understood than in other parts. Thus in Mechanics the relations between phe nomens have been so well ascertained that we are able to start from a few simple laws regarding the motions of bodies and from these deduce explanations of the most complicated motions. In other parts of the subject we must be content to take from time to time some one principle and trace the logical consequences of it as far as we can, and then proceed to do the same with other principles. After classifying and studying a group of facts, the process by which we arrive at some underlying principle is called Induction. Thus the principle of gravitation was discovered by Newton after a careful comparison Of the motions of falling bodies and Of the moon and the planets. Having found a general principle underly ing and binding together many phenomena, we may reason forward from it and deduce other known or unknown facts, as in Geometry we deduce one proposition from another. This process is called Deduction. In a brief account Of Physics we must necessarily use deductive more frequently than inductive methods; but, where space will permit, the effort may be made to show how by induc tion important fundamental principles have been discovered. 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.