Excerpt from The Popular Science Monthly, Vol. 14: November, 1878, to April, 1879 A sheet of red, the other on a sheet of green paper, as indicated in Fig. 1, it will be found that the red square on the red paper will not appear nearly so brilliant and saturated in color as that placed on the green ground; hence the observer will be disposed to doubt whether the two. 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.