Excerpt from Use of Electricity in the Control of Sea Lampreys: Electromechanical Weirs and Traps and Electrical Barriers Voltage gradients created in the water during each test conducted were measured, recorded, and correlated with effects on fish and lampreys. A specially designed probe and a vacuum tube voltmeter were used to obtain these measurements. A more detailed description of test instruments is included in a later section. 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.