Excerpt from Life Testing of Incandescent Lamps at the Bureau of Standards The introduction Of new classes Of lamps, however, rendered it advisable to make considerable changes in the original photo metric equipment and in the details of the method Of testing. These changes have been made from time to time by those who have been most intimately associated with the work. The equip ment as it now stands and the present method Of the Bureau's life-testing procedure in all its details are, therefore, the result Of a gradual development in which various persons have been Of assistance. From the beginning the magnitude Of the work of inspection and life testing has been constantly increasing year by year in consequence of the natural growth of the Government's pur chases Of incandescent lamps. Fortunately, however, the quality Of the lamps supplied has, in most cases, been fairly uniform and also above the requirements Of the specifications, so that full and reliable data on the lamps supplied by each manufacturer have been Obtained by submitting to life test a yearly total of not over lamps which represent about one and a quarter millions of inspected lamps. 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.