Excerpt from Notes on the Chemical Lectures in the Medical Department of the University of Pennsylvania: For First-Year Students Natural Philosophy. General Philosophy. Chemistry. Astronomy. Chemistry is that branch of physics, or the science, which treats of the properties and laws relating to the ultimate molecules and atoms of matter. Science is the knowledge of the laws pertaining to any given class of phenomena. Chemistry became a fixed science in 1774, when oxygen was discovered. 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.