Excerpt from Publications of the Astronomical Society of the Pacific, 1903, Vol. 15 As the light of the sky cannot be concentrated at a point, we must, if we wish to get its value in terms of the light of a star of a certain magnitude, take some means to spread out the light of the star. It was at first thought that this might be accomplished by inserting a photographic plate a few inches behind the focus of a photographic telescope. The Crocker telescope (6 inches aperture and 33 inches focus) was first used for this purpose. A rapid plate (cramer Crown) was exposed for one hour on Vega, about 25 centimeters out of focus. Aii impression centimeters in diameter was formed on the plate, but it was found that the light was very unevenly distributed. The impression was made up of small dark granules surround ed by lighter Circles. A straight gash ran nearly across the center of the circle, and there were also several smaller curved gashes. A 'second plate showed exactly the same pattern, which is clue, I suppose, to lack of homogeneity in the glass of the lenses. Similar tests with another lens gave somewhat bet ter results, but not sufficiently good for the purpose. This method had therefore to be abandoned. 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.