440 Lunar Shetches. 



remark applies to his observation of 1797, Feb. 6, when he 

 discovered, with a power of 288, the cleft already described on 

 the N.E. side of the glacis, and when he says the terraces of 

 the ring were so sharply defined that he felt as though he 

 could climb them. Contrast this with the fact that, without 

 any previous knowledge of its existence, and without any 

 special attention to its site, I detected this object, 1832, April 

 9, with an aperture of 3-inches of an ill- corrected fluid achro- 

 matic, bearing a power somewhere about 100.) — 1864, March 

 17. 5|-inch; Copernicus entered more than its own breadth. 

 " There are wonderful radiating streams, as of a continuous 

 succession of blocks, or of lava cracked and roughened in 

 cooling, extending to a long distance on every side. They are 

 most visible in the present illumination through the E. semi- 

 circle — least distinct S.W. Through the W. semicircum- 

 ference these streams seem to cover all the glacis even from the 

 top of the wall; on the opposite shadowy side the terraces are 

 so strongly marked that the radiations do not appear across 

 them, though they cover the slope beneath. The S. half of 

 the interior (or rather the S.E. quadrant, the S.W. being in 

 shade) is all strewed with blocks — especially with 212 [a very 

 keenly defining microscopic eye-piece] ; the N. part is much 

 smoother/' — 1864, March 18. 5^-inch. Terminator just be- 

 yond Sin. Iriduni, and touching W. wall of Gassendi. " The 

 interior terraces are shown by their shadow to have a convex 

 outline, from the foot of the highest wall to the floor, indi- 

 cating, perhaps, that in settling down the upper part was the 

 most fluid/' 



1864, Dec. 8, 5i-in. Terminator through Heraclides. "A. 

 strange observation — definition marvellously sharp — I have 

 very rarely seen it matched ; but low clouds hanging around, 

 and dissolving into rain so close over our heads, that when 

 one of them was passing as a haze across the Moon, I found, 

 by lengthening the focus, that a profusion of the minutest 

 dark globules were streaming over the disc from the W. 

 (somewhat like Messier's "observation of the Sun), notwith- 

 standing which the details, though pale from haze and a 

 considerable amount of dew and rain on the object-glass, 

 continued sharp, and the limb was fairly defined even when 

 I tried a power (461 and Barlow lens reversed) which must 

 have approached 700 or 800. Copernicus glorious, full of 

 details, almost like Secchi [the engraviiig]. The S. half of 

 the floor is very irregular ; the unevennesses have more the 

 aspect of streams flowing from the central cones than of single 

 blocks. There is some, but a less degree of roughness in the 

 N.W. quarter; I trace none in the N.E." [The particulars 

 of this observation are given in full, as being instructive in 



