Excerpt from The Effects of Tension and Quality of the Metal Upon the Changes in Length Produced in Iron Wires by Magnetization That the two flrst laws are correct for the flelds that Joule used cannot be doubted; but as to the thlrd law there 18 much uncertalnty. The 1nvestigat10ns of Shelford Bldwell 1ndlcate that not only hardenlng but also anneallng, an 1ron rod dlminish the elongatlng effect, and at the best the relatlon between the softness of the 1ron and lts change of length 1s to - day very much confused. 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.