Excerpt from Selenography: Read Before the Astronomical Section of the Hamilton Scientific Association, April 29th, 1902 Although a lunation is, in many respects, a desirable standard for measuring time, it has been found extremely difficult to make it a sub-division of the tropical year, or the time taken by the earth to complete her course from, and return to, the vernal equinox. Where ever the lunisolar year has been adopted intercalations have been necessary to bring the lunar months and solar years out' even. The Greeks used simultaneously the two standards, and had no end of difficulty to keep them from overlapping. Their Olympiads supply a record for a thousand years, and are perhaps the best scale of past events on record. They originated from holding, every four years. 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.