Excerpt from Annual Record of Science and Industry for 1872 The present volume is the second of a series in which it is proposed to present, year by year, the most important discoveries in the various branches of science, theoretical and applied - the selection of subjects being made, prima rily, on the ground of their absolute importance, as marking the stages of scientific advancement; and, secondarily, as being of interest to the general reader. A general sum mary of progress for the year in the different departments, prefixed to the volume, is intended to give a connected sketch of what has actually been accomplished. It will, of course, be readily understood that, in the com pass of a single duodecimo volume, it is impossible to do more than touch very briefly upon what appear to be the more noteworthy subjects. As far as the specialist is con cerned, he must necessarily have recourse, for full informa tion, to the Journals or year-books devoted to his partie ular department, of which scarcely any branch of science is at present destitute. 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.