Lunar Sketches. 441 



their own way. They show under what unexpected circum- 

 stances the greatest distinctness may be found; and that, 

 therefore, no night should be condemned untried ; and that it 

 is extremely difficult for an inexperienced person to form, from 

 a brief trial on celestial objects, an accurate opinion of the 

 quality of any large instrument : small apertures are far less 

 affected by atmospheric disturbance.] — 1865, Mar. 6, 5-£-in. 

 Central hill beginning to appear. " Copernicus very magnificent, 

 covered with hillocks and roughnesses, which, under the pre- 

 sent illumination, so extend over the terraces of the ring that 

 the summit of the latter does not appear as though it rose 

 clear above the external lava-streams, but as though they had 

 flowed over it."—] 866, Feb. 23, 5^-in. " W. ring just be- 

 ginning to come on terminator : marvellously rough glacis, 

 but no distinct radiation. — 1867, Dec. 5, 9^- in. mirror. "It 

 is very interesting to mark the contrast between the bright 

 white illumination of the interior of the wall and its terraces 

 on the E. and the colossal heaps of grey scoriae, which look 

 as if they had been rolled over the summit of the ring on 

 every side, and remained piled one above another even to its 

 summit ; it being quite evident in this illumination that the 

 wall has nowhere a distinct existence above them. The radia- 

 tions, which are very clear, do not begin till a long way 

 below." 2h. later, when the ring was distant a diameter from 

 term., it is noted that the E. side, " at some little distance from 

 its summit, casts a black shadow for a considerable length, 

 giving the mistaken impression of a perpendicular cliff, or 

 even overhanging edge, so that there must be a sudden increase 

 of declivity at this part j the radiations are all below, and the 

 upper part of the ring looks exactly as though it had been rolled 

 over the lip of the crater, or forced by pressure out of the 

 interior, subsequent to the formation of the radiated surface ; 

 the lava- currents, if they are such, and not streams of blocks 

 or scoriae, must have been in a more fluid condition than the 

 wall, both as extending further, and over a more gentle slope. 

 The internal terraces look as though they had resulted from 

 the slipping back into the interior of matter which had failed 

 to be projected over the lip." l|h. afterwards, "the black 

 shadow is passing off, and there is a distinct impression that 

 the ring proper is convex on the outside in a vertical section," 

 as the' terraces, at least W., had been found to be in the 

 interior. " Above this there is a low, narrow, irregularly bent 

 central crest or lip, of considerable steepness, which seems to 

 divide the ring proper — i.e., the convex part without, and the 

 terraces within, into nearly equal parts in point of horizontal 

 extent." My powerful reflector exhibits with ease the curious 

 vertical gullies which cut down for a short distance the inner 



