Some reflections upon the moon considered as a world, in reference to questions of habitability, and to the peculiar conditions which would attend a sojourn on the lunar surface, have appeared to us not inappropriate. These, though instructive, are rather curious than important. More worthy of respectful consideration are the few remarks we have offered upon the moon as a satellite and a benefactor to the inhabitants of this Earth. In reference to the Illustrations accompanying this work, more especially those which represent certain portions of the lunar surface as they are revealed by the aid of powerful telescopes, such as those which we employed in our scrutiny, it is proper that we should say a few words here on the means by which they have been produced.—— During upwards of thirty years of assiduous observation, every favourable opportunity has been seized to educate the eye not only in respect to comprehending the general character of the moon’s surface, but also to examining minutely its marvellous details under every variety of phase, in the hope of rightly understanding their true nature as well as the causes which had produced them. This object was aided by making careful drawings of each portion or object when it was most favourably presented in the telescope. These drawings were again and again repeated, revised, and compared with the actual objects, the eye thus advancing in correctness and power of appreciating minute details, while the hand was acquiring, by assiduous practice, the art of rendering correct representations of the objects in view. In order to present these Illustrations with as near an approach as possible to the absolute integrity of the original objects, the idea occurred to us that by translating the drawings into models which, when placed in the sun’s rays, would faithfully reproduce the lunar effects of light and shadow, and then photographing the models so treated, we should produce most faithful representations of the original. The result was in every way highly satisfactory, and has yielded pictures of the details of the lunar surface such as we feel every confidence in submitting to those of our readers who have made a special study of the subject. It is hoped that those also who have not had opportunity to become intimately acquainted with the details of the lunar surface, will be enabled to become so by aid of these Illustrations. In conclusion, we think it desirable to add that the photographic illustrations above referred to are printed by well-established pigment processes which ensure their entire permanency. CONTENTS. PAGE