Hans Christian Ørsted (1777-1851) was one of the leading scientists of the nineteenth century, having played a crucial role in founding electromagnetism. Unfortunately for the English-speaking world, almost all of his research was published in other languages, particularly his native Danish. This book will help to elevate Ørsted to his rightful place in the history of science by finally making his most important scientific works available in English. The book includes, for example, Ørsted's account of his revolutionary experiments in electromagnetism. In 1820, he discovered that a compass needle deflects from magnetic north when an electric current is switched on or off in a nearby wire. This showed that electricity and magnetism were related phenomena, a finding that laid the foundation for the theory of electromagnetism and for research that later created such technologies as radio, television, and fiber optics. The unit of magnetic field strength was named the Ørsted in his honor. Selections here also show the extraordinary breadth of Ørsted's interests, which range through a long and prolific career from the study of plant alkaloids and the compression of fluids to the nature of light and the "natural science" of beauty. The writings are taken from scientific papers, Ørsted's correspondence, and reports of the Royal Danish Academy of Sciences and Letters. The book will not only draw long overdue attention to Ørsted's own work but will also shed new light on the nature of scientific study in the nineteenth century. Originally published in 1998. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.