The Nature Study Review Volume 17 PDF Download

Excerpt from Nature-Study Review, Vol. 17: Devoted to Elementary Science in the Schools The construction of a sun-dial and the setting it up properly should he a delightful means of educating the pupils in a very important subject, the measuring of time, - a subject which is given very little thought in this day of clocks and watches. Even during the discussion of "time saving" turning back the clock an hour, very few understood its real meaning. Sun-dials are very ancient of origin; and probably the earliest form was a pole fixed in the ground with the spaces covered by its shadow during the day divided and marked by stones or in some other manner. The earliest mention of a sun-dial is found in Isaiah xxxviii, 8: "Behold, I will bring again the shadow of the degrees which is gone down in the sun-dial of Ahaz ten degrees backward." This must have been written about 700 years B. C. but we have no idea of the form of this dial. The earliest dial, the construction of which we know, was made by the Chaldean astronomer Berossus who lived about 300 B. C. and it consisted of a hollow hemisphere with its rim horizontal and a bead fixed at its center which cast a shadow, the path of which was an arc which was divided into twelve equal parts. This form of dial was used many centuries by many peoples. No one knows certainly when the first clock was invented nor by whom, but the use of clocks in Europe in the 13th century has been recorded. 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.