[Illustration: GASSENDI. Nov. 7. 1867 10 P.M.] THE MOON: CONSIDERED AS A PLANET, A WORLD, and A SATELLITE. BY JAMES NASMYTH, C.E. AND JAMES CARPENTER, F.R.A.S. LATE OF THE ROYAL OBSERVATORY, GREENWICH. WITH TWENTY-FOUR ILLUSTRATIVE PLATES OF LUNAR OBJECTS, PHENOMENA, AND SCENERY; NUMEROUS WOODCUTS, &c. LONDON: JOHN MURRAY, ALBEMARLE STREET. 1874. LONDON: BRADBURY, AGNEW, & CO., PRINTERS, WHITEFRIARS. TO HIS GRACE THE DUKE OF ARGYLL, IN RECOGNITION OF HIS LONG CONTINUED INTEREST IN THE SUBJECT OF WHICH IT TREATS, _This Volume_ IS MOST RESPECTFULLY DEDICATED BY THE AUTHORS. PREFACE. The reason for this book’s appearance may be set forth in a few words. A long course of reflective scrutiny of the lunar surface with the aid of telescopes of considerable power, and a consequent familiarity with the wonderful details there presented, convinced us that there was yet something to be said about the moon, that existing works on Astronomy did not contain. Much valuable labour has been bestowed upon the topography of the moon, and this subject we do not pretend to advance. Enough has also been written for the benefit of those who desire an acquaintance with the intricate movements of the moon in space; and accordingly we pass this subject without notice. But very little has been written respecting the moon’s physiography, or the causative phenomena of the features, broad and detailed, that the surface of our satellite presents for study. Our observations had led us to some conclusions, respecting the cause of volcanic energy and the mode of its action as manifested in the characteristic craters and other eruptive phenomena that abound upon the moon’s surface. We have endeavoured to explain these phenomena by reference to a few natural laws, and to connect them with the general hypothesis of planet formation which is now widely accepted by cosmologists. The principal aim of our work is to lay these proffered explanations before the students and admirers of astronomy and science in general; and we trust that what we have deduced concerning the moon may be taken as referring to a certain extent to other planets.