Excerpt from Knowledge and Illustrated Scientific News, 1905, Vol. 2: January to December, 1905 Now there is a decided periodicity in spot activity. For some years only a few spots become visible, while a little later they become more numerous until a maxi mum is reached, after which they begin to dwindle again in numbers until the succeeding minimum is attained when the sun remains spotless for months together. The accompanying diagram (fig. 2) will give the reader a good idea of this variation. The dark portion, which looks like a silhouette of a cathedral city, shows the change of the amount of spottedness of the sun for each solar rotation from the year 1867 to 1879 the arrows indicate the. Epochs or times, as determined from a curve specially smoothed for this purpose, when there are fewest (minimum) or most (maximum) spots. It will be noticed that there is not a gradual increase of spotted area. 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.