Excerpt from A New Determination of the Ratio of the Electromagnetic to the Electrostatic Unit of Electricity This method gave as good results as we had anticipated, but in the meantime we had so much improved the work with the spher ical condensers that the results with the cylinders were not satis factory. We then added a fourth pair of cylinders to the set and insulated the two end sections of the inner cylinders so that they formed guard cylinders, after the manner of the guard rings of a plate condenser. The upper guard cylinder was provided with a micrometer screw, so that the breadth of the air gap could be varied and the computed correction for the gap checked by experimental determinations with varying widths. The use of the guard cylin ders necessitated a modification of the rotating commutator for charging and discharging the condensers, by adding three brushes on the opposite side of the ring, so that the middle cylinders and the guard cylinders could be charged and discharged simultaneously. Using the guard cylinders in this way we obtained results of much greater uniformity and greater apparent accuracy than we had expected. 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.