PREFACE.
Astronomers are so frequently obliged to recur to observations made during former ages for the purpose of supporting the results of the observations of the present day, that there is a special inducement for them to study the historical development of their science. Much labour has accordingly been spent on the study of the history of astronomy, and in particular the progress of the science in the sixteenth and seventeenth centuries has of late years formed the subject of many important monographs. The life of Copernicus has been written in considerable detail by Prowe, Hipler, and others. Of Kepler's numerous works we owe a complete edition to the patient industry and profound learning of the late Dr. Frisch of Stuttgart, while the life of Galileo, and particularly his persecution and trial, have called forth quite a library of books and essays. In the present volume I have attempted to add another link to the chain of works illustrating the birth of modern astronomy, by reviewing the life and work of Tycho Brahe, the reformer of observational astronomy.
Although not a few monographs have been published from time to time to elucidate various phases in the career of Tycho Brahe, while several popular accounts of his life (by Helfrecht, Brewster, &c.) have appeared, the only scientific
