Excerpt from Addition Theorems for Spherical Waves In order to carry out this approximation it is necessary to de compose the scattered field of a sphere with center at 0 into incoming spherical waves for a second sphere with center at O'. Such a decomposi tion requires an addition theorem which expresses a spherical wave with center at O, in terms of spherical waves with center at O'. Such an expansion or addition theorem for cylindrical waves is well known1 Using this expansion, Twersh'y2 was able to calculate the scattered field obtained by a plane wave striking a configuration of cylinders, taking into account the contributions to the excitations of a particular element by the radiation scattered by the remaining elements. The analogous case of a plane wave striking a configuration of spheres may be treated with the help of the addition theorems we have obtained in this paper. 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.