Excerpt from The Testing of Machine Tools From the general point of view the common function of all machines may be regarded as the performance of work or the production of output, no special defini tion being given to the meaning of either work Or output when used in this connection, since both vary considerably and depend in any particular case upon the kind of machine to which they have reference. In any case, however, we generally sup pose that the work or output is (either immediately or ultimately) of a more or less useful character so far as mam - individually or collectively - is con cerned, though there are, undoubtedly, exceptions even to this excellent rule in regard to the utility of individual mechanical processes and machines. 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.