Excerpt from Theory of Measurements: A Manual for Physics Students Personal Errors. These are. Errors characteristic of the individual observer. If we swing a pendulum before a class of students and ask them to indicate the times of greatest displacement by tapping with their pencils, the result will well illustrate the personal equation. In the experiment in wireless telegraphy by which time messages were sent from Paris to Arlington, each observer was carefully rated in order that this error should be guarded against. Mistakes are, unfortunately, too common in students' laboratory work to call for an extended explanation. Errors in reading scales, in computation, and in tabulation may be classed as mistakes, and these should become less and less frequent as the student gains experience. 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 techlogy 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.