KEPLER'S SYSTEM OF REGULAR SOLIDS. KEPLER. SYMBOLICAL REPRESENTATION OF THE PLANETARY SYSTEM. THE COMMEMORATION OF THE RUDOLPHINE TABLES. WOOLSTHORPE MANOR. TRINITY COLLEGE, CAMBRIDGE. DIAGRAM OF A SUNBEAM. ISAAC NEWTON. SIR ISAAC NEWTON'S LITTLE REFLECTOR. SIR ISAAC NEWTON'S SUN-DIAL. SIR ISAAC NEWTON'S TELESCOPE. SIR ISAAC NEWTON'S ASTROLABE. SIR ISAAC NEWTON'S SUN-DIAL IN THE ROYAL SOCIETY. FLAMSTEED'S HOUSE. FLAMSTEED. HALLEY. GREENWICH OBSERVATORY IN HALLEY'S TIME. 7, NEW KING STREET, BATH. From a Photograph by John Poole, Bath. WILLIAM HERSCHEL. CAROLINE HERSCHEL. STREET VIEW, HERSCHEL HOUSE, SLOUGH. From a Photograph by Hill & Saunders, Eton. GARDEN VIEW, HERSCHEL HOUSE, SLOUGH. From a Photograph by Hill & Saunders, Eton. OBSERVATORY, HERSCHEL HOUSE, SLOUGH. From a Photograph by Hill & Saunders, Eton. THE 40-FOOT TELESCOPE, HERSCHEL HOUSE, SLOUGH. From a Photograph by Hill & Saunders, Eton. LAPLACE. THE OBSERVATORY, DUNSINK. From a Photograph by W. Lawrence, Dublin. ASTRONOMETER MADE BY SIR JOHN HERSCHEL. SIR JOHN HERSCHEL. NEBULA IN SOUTHERN HEMISPHERE. THE CLUSTER IN THE CENTAUR. OBSERVATORY AT FELDHAUSEN. GRANITE COLUMN AT FELDHAUSEN. THE EARL OF ROSSE. BIRR CASTLE. From a Photograph by W. Lawrence, Dublin. THE MALL, PARSONSTOWN. From a Photograph by W. Lawrence, Dublin. LORD ROSSE'S TELESCOPE. From a Photograph by W. Lawrence, Dublin. ROMAN CATHOLIC CHURCH, PARSONSTOWN. From a Photograph by W. Lawrence, Dublin. AIRY. From a Photograph by E.P. Adams, Greenwich. HAMILTON. ADAMS. THE OBSERVATORY, CAMBRIDGE. INTRODUCTION. Of all the natural sciences there is not one which offers such sublime objects to the attention of the inquirer as does the science of astronomy. From the earliest ages the study of the stars has exercised the same fascination as it possesses at the present day. Among the most primitive peoples, the movements of the sun, the moon, and the stars commanded attention from their supposed influence on human affairs. The practical utilities of astronomy were also obvious in primeval times. Maxims of extreme antiquity show how the avocations of the husbandman are to be guided by the movements of the heavenly bodies. The positions of the stars indicated the time to plough, and the time to sow. To the mariner who was seeking a way across the trackless ocean, the heavenly bodies offered the only reliable marks by which his path could be guided. There was, accordingly, a stimulus both from intellectual curiosity and from practical necessity to follow the movements of the stars. Thus began a search for the causes of the ever-varying phenomena which the heavens display.