Excerpt from Index to the Journal of the Franklin Institute (Including the Franklin Journal) For the One Hundred and Twenty Volumes From 1826 to 1885: Arranged According to Subjects and Authors In preparing an index to a work of 120 volumes embracing a record of the progress of the sciences and the arts, during a period of sixty years, in which many theories have been pre sented, modified, or discarded, and many new arts created, and in which many words have undergone changes in signification, numerous difficulties presented themselves. A perfect index under the circumstances would imply a complete knowledge of all the heterogeneous materials in the work, and of the history of the progress of the sciences and the arts during the period of its publication. In editing the work for publication it became obvious that a too rigorous adherence to the phraseology of titles on the part of the compiler greatly multiplied the difficulties, and would impair the usefulness of the work. It was, therefore, found necessary to rewrite much of it so as to adapt it better to the user's point of view. 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.