This book details the groundbreaking work of David Gill and his team at the Royal Observatory Cape of Good Hope in determining the parallax of numerous stars using the advanced technology of the heliometer. The observations made here were instrumental in advancing our understanding of the scale of the universe. A must-read for any astronomy enthusiast or historian. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

Excerpt from Heliometer Observations for Determination of Stellar Parallax Made at the Royal Observatory, Cape of Good Hope The instrument as employed at Mauritius and Ascension is fully described in the Dun Echt publications, Vol. II. For use at the Cape I could not obtain the original equatoreal mounting, and therefore ordered a new stand for the Heliometer tube and cradle from Sir H. Grubb of Dublin, taking advantage of the opportunity thus offered to have some alterations made on the instrument which previous experience had proved to be desirable. These alterations were chiefly in connexion with the slow motion of the tube in position-angle. In the original instrument the quick motion in position angle was accomplished by turning a rod, which carried a pinion which acted on a wheel of which the Heliometer tube formed the axis. Slow motion was given by rotating this rod very slowly by means of a toothed wheel acted on by a tangent screw, but the effect was to create a certain amount of torsion of the rod before any rotation of the tube took place, so that there was wanting that immediate and precise response to the observer's action which is essential for easy and accurate measurement. I therefore planned the following arrangement. 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.