Excerpt from Report on the Total Eclipse of the Sun: Observed at Mina Bronces, Chile, on April 16, 1893

It was decided that if the Lick Observatory could secure the necessary funds to send out an expedition, some point in the interior of Chile should be selected for observing the eclipse, as the atmospheric conditions throughout the Desert of Atacama were known to be excellent. Mrs. Phebe hearst, a friend of the Observatory, had provided in 1892 a fund which was to be used in aid of scientific undertakings at the Observatory. On the recommendation of the Director of the Observatory, and with her cordial sanction, the sum of from the hearst Fund was set aside for the expenses of the expedition in the field. The Regents of the University authorized the use of the necessary instruments.

Preparations for the eclipse were commenced in the fall of 1892. I was particularly desirous of photographing certain phenomena on a very much larger scale than had ever before been done, for it seemed that only in this way could certain doubtful points be decided, and marked advantages be gained over the usual results.

The finer details of the corona are necessarily lost in photo graphs taken on a small scale. Special attention was therefore first given to the designing of an instrument which should be capable of furnishing satisfactory results on a very large scale when used under the peculiar conditions presumably prevailing in the interior of Chile.

The excellent clark Objective of 5 inches aperture and 40 feet focal length, specially corrected for the photographic rays, seemed to' be the lens most suitable for this purpose. It forms part of the horizontal photo-heliograph of the Lick Observatory. In deciding upon the method of mounting it was never for a moment thought practicable to use the ordinary equatorial form in which the tube is suspended near the middle of its length, on account of the great expense attending the completion of such a plan, and for the still more serious reason of its instability in an exposed position at a high altitude, where the atmospheric movements are often quite strong. Any advantage due to the large scale given by a telescope 40 feet long will, in a great measure, be lost unless great stability of the image on the photographic plate is secured.

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.