A high power gives us little more evidence than a low one upon the nature of the long bright streaks that radiate from some of the more conspicuous craters, but it enables us to see that those streaks do not arise from any perceptible difference of level of the surface—that they have no very definite outline, and that they do not present any sloping sides to catch more sunlight, and thus shine brighter, than the general surface. Indeed, one great peculiarity of them is that they come out most forcibly where the sun is shining perpendicularly upon them; hence they are best seen where the moon is at full, and they are not visible at all at those regions upon which the sun is rising or setting. We also see that they are not diverted by elevations in their path, as they traverse in their course craters, mountains, and plains alike, giving a slight additional brightness to all objects over which they pass, but producing no other effect upon them. To employ a commonplace simile, they look as though, after the whole surface of the moon had assumed its final configuration, a vast brush charged with a whitish pigment had been drawn over the globe in straight lines radiating from a central point, leaving its trail upon everything it touched, but obscuring nothing. Whatever may be the cause that produces this brightness of certain parts of the moon without reference to configuration of surface, this cause has not been confined to the formation of the radiating lines, for we meet with many isolated spots, streaks and patches of the same bright character. Upon some of the plains there are small areas and lines of luminous matter possessing peculiarities similar to those of the radiating streaks, as regards visibility with the high sun, and invisibility when the solar rays fall upon them horizontally. Some of the craters also are surrounded by a kind of aureole of this highly reflective matter. A notable specimen is that called _Linné_, concerning which a great hue and cry about change of appearance and inferred continuance of volcanic action on the moon was raised some years ago. This object is an insignificant little crater of about a mile or two in diameter, in the centre of an ill-defined spot of the character referred to, and about eight or ten miles in diameter. With a low sun the crater alone is visible by its shadow; but as the luminary rises the shadow shortens and becomes all but invisible, and then the white spot shines forth. These alternations, complicated by variations of atmospheric condition, and by the interpretations of different observers, gave rise to statements of somewhat exaggerated character to the effect that considerable changes, of the nature of volcanic eruptions, were in progress in that particular region of the moon.