Excerpt from Interferometer Measurements of the Longer Wavelengths in the Iron Arc Spectrum Column 2 contains the new wave-length values obtained by direct comparison with the primary standard, and in the two succeeding columns the number of observations and the probable error of the mean value are given for each line. A indicates a probable error less than A, B, to A, and C means that the determination is poor. Columns 5 and 6 present the values and probable errors published by Burns and in the next column the values obtained by Eversheim are re peated. In the last two columns are presented, for purposes of comparison with preceding values, the present values of the international secondary standards and the interpolated values adopted by the International Astronomical Union.9 In order to make comparisons with a considerable number of the accepted secondary standards we begin our table with 5434 A, thus includ ing 25 standards, 4 of which belong to group (i. 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.