Excerpt from The Variation of Resistances With Atmospheric Humidity The possibility of these changes being due to atmospheric humidity suggested itself, but it was not at first evident how an increase of resistance could be produced by an increase of humidity. The effect of leakage arising from moisture deposited on the coils or upon the tops of resistance boxes is of course to decrease the resistance, and this effect would increase with the humidity. In order to ascertain the cause of the marked change in the opposite direction, to determine its magnitude, and to find how to prevent it, we took up last November a systematic study of the question. It was very soon found that changes such as occurred during an interval of six months in the atmosphere of the laboratory could be induced in a few days by placing the resistances in a closed case in which an atmosphere of high humidity was maintained, although it usually required several weeks for the resistance of a coil to reach a maximum, or to return to its former value when restored to the original conditions of humidity. Two apparatus cases were employed, the atmosphere within one being kept at a nearly constant relative humidity of about 25 per cent, the other being kept at higher humidities, ranging from 40 to 100 per cent, although seldom higher than 80, and oftenest about 60 per cent. Each case was provided with thermometers and record ing hygrometers, the latter being frequently calibrated by aspiration psychrometers. 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.