Excerpt from An Elementary Treatise on Astronomy: Adapted to the Present Improved State of the Science, Being the Fourth Part of a Course of Natural Philosophy, Compiled for the Use of the Students of the University at Cambridge, New England Tm: following treatise was selected from Biot's Traite Elemcntaire d' Astronomie Physique, 2d edition, printed at Paris in Although the original is in three vol umes octave, all the body of the work is retained in this translation, except what relates to a description of astro nomical instruments, the construction of tables, the tem perature of the earth, the determination of certain astro nomical periods, used in chronology, and two or three other topics anticipated in the parts of this course already published. A few only of the notes are given, and these are subjoined at the end in the form of an Appendix. The centesimal notation of the original has been changed to the sexagesimal; and alterations and additions have, in'a few instances, been made for the purpose of adapt ing the work to the latest discoveries and improvements. 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.