Prize Essay on the Distribution of the Moon's Heat and Its Variation With the Phase

Excerpt from Prize Essay on the Distribution of the Moon's Heat and Its Variation With the PhaseThe bolometer used in this research exposes a sensitive surface of about 19 sq. Mm. It is covered by a diaphragm of white card pierced by a central circular aperture, cm. In diameter, which permits a more accurate setting, especially in the condition of tangency to the moon's limb. The part of the image of the moon selected for measurement is brought to coincide with this aperture by the adjusting cords of the siderostat, all the coarser details of the surrounding lunar surface being readily seen on the White card. The adjustment having been made, the clock-work of the siderostat is trusted to keep the image fixed within small limits which will be described further on.The siderostat-mirror, (also of glass silvered on the front surface) is large enough to give a beam which more than covers the concave mirror at all times, and the second mirror being placed centrally in the path of the horizontal reflected beam, with its Optical axis slightly inclined to the direction of the former, gives an image on the white card bright enough, as has been said, to be readily seen in much of its detail, and hot enough to give, with the extremely sensitive heat measuring apparatus, a deflection of nearly 100 mm. Divisions on the galvanometer scale from the small part near the center of the disc of the full moon.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis 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.