Excerpt from Elements of Precise Surveying and Geodesy Mistakes are errors due to such serious mental confusion that the Observation cannot be regarded with any confidence, as for instance writing 53 when 35 is intended. Observa tions affected with mistakes must be rejected, although when these are of small magnitude it is sometimes not easy to distinguish them from errors. Accidental errors are those that still remain after all con stant errors and mistakes have been carefully investigated and eliminated. Such, for example, are the errors in leveling arising from sudden expansions Of the bubble and standards, or from the effects of the wind, or from irregular refraction. They also arise from the imperfections of human touch and Sight, which render it difficult to handle instruments delicately or to read verniers with perfect accuracy. These are the errors that exist in the final observations and whose discus sion forms the subject of this chapter. However carefully the measurements. Be made, the final Observations do not agree; all of these observations cannot be correct, since the quantity has only one value, and each Of them can be regarded only as an approximation to the truth. The absolutely true value Of the quantity in question cannot be ascertained, but instead of it one must be deter mined, derived from the combination Of the Observations, which shall be the most probable value, that is to say, the value which is probably most nearly to the truth. 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.