Excerpt from Studies From the Psychological Laboratory of the University of California, 1900: Reprinted From the Psychological Review<br><br>The smallest lateral difference of place that is visible has until recently been given as about 50 - 6o angular measure. The method employed by Helmholtz and others1 in reaching this result was the well-known one of bringing two parallel lines together until they finally are just distinguished as two on the same general principle by which Weber determined the tactile space-threshold, by finding the distance between two compass - points that just cease to merge into one.<br><br>But by a different method it is now evident that a lateral difference 2 of place of about 7 of arc can be directly perceived.<br><br>About the Publisher<br><br>Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com<br><br>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.