that "we know far too little respecting the real details of lunar scenery to form any satisfactory opinion on the subject. If a landscape-painter were invited to draw a picture presenting his conceptions of the scenery of a region which he had only viewed from a distance of a hundred miles, he would be under no greater difficulties than the astronomer who undertakes to draw a lunar landscape, as it would actually appear to any one placed on the surface of the moon. "We know certain facts—we know that there are striking forms of irregularity, that the shadows must be much darker as well during the lunar day as during an earth-lit lunar light, than on our own earth in sunlight or moonlight, and we know that, whatever features of our own landscapes are certainly due to the action of water in river, rain, or flood, to the action of wind and weather, or to the growth of forms of vegetation with which we are familiar, ought assuredly not to be shown in any lunar landscape. But a multitude of details absolutely necessary for the due presentation of lunar scenery are absolutely unknown to us. Nor is it so easy as many imagine to draw a landscape which shall be correct even as respects the circumstances known to us. For instance, though I have seen many pictures called lunar landscapes, I have never seen one in which there have not been features manifestly due to weathering and to the action of running water. The shadows, again, are never shown as they would be actually seen if regions of the indicated configuration were illuminated by a sun, but not by a sky of light. Again, aerial perspective is never totally abandoned, as it ought to be in any delineation of lunar scenery. I do not profess to have done better myself in the accompanying lunar landscapes. I have, in fact, cared rather to indicate the celestial than the lunarian features shown in these drawings. Still, I have selected a class of lunar objects which may be regarded as, on the whole, more characteristic than the mountain-scenery usually exhibited. And, by picturing the greater part of the landscape as at a considerable distance, I have been freer to reproduce what the telescope actually reveals. In looking at one of these views, the observer must suppose himself stationed at the summit of some very lofty peak, and that the view shows only a very small portion of what would really be seen under such circumstances in any particular direction. The portion of the sky shown in either picture extends only a few degrees from the horizon, as is manifest from the dimensions of the earth's disk; and thus it is shown that only a few degrees of the horizon are included in the landscape."
Our author then pictures the aspect of the lunar heavens by night and by day. "We have space but for a few passages from this description: "To an observer stationed upon a summit of the lunar Apennines on the evening of November 1, 1872, a scene was presented unlike any known to the inhabitants of earth. It was near the middle of the long lunar night. On a sky of inky blackness stars innumerable were spread, among which the orbs forming our constella-
