Excerpt from Optical Radiation Measurements: Fundamental Principles of Absolute Radiometry and the Philosophy of This Nbs Program (1968 to 1971) Key words: Absolute detector radiometry; electrically calibrated detectors; International Pyrheliometric Scale; irradiance; radiometry. 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.