The Lectures contained in this volume have been delivered at gresham college during the last two years. In response to various requests, and by the kind and liberal assistance of the gresham committee of the City of London, to whom the author desires to tender his grateful thanks, they are now published. In the description of the Planets and Satellites which they contain, such information as may be found in almost every astronomical text-book is brieﬂy recapitulated that which is less familiar, or of recent announcement, is discussed more fully. In the case of the Sun and Moon it has only been possible to mention a few points of Special interest. Those who desire fuller information may consult the larger works of Professor Young, Mr. Proctor, and the late Padre Secchi, upon the Sun; of Mr. Neison, Mr. Proctor, and others, upon the Moon. The time and space at the author's disposal have prevented him from making more than a passing reference to the cometary and meteoric members of the Solar System.