874 Lunar Details. 



ively minute, arid that it would be distinctly visible in instru- 

 ments having not more than a tenth or twentieth part of the 

 power of those employed by him. If, therefore, we were to 

 infer that this manifold outburst had taken place some time at 

 the beginning' of the present century, our argument would not 

 want plausibility. It can, however, be only advanced with 

 hesitation, especially in the face of such an authority as 

 Schmidt, who asserted (previous to the much controverted 

 discovery as to Linne) that no single region of the Moon had 

 been sufficiently investigated, even with only a 5-ffc. refractor, 

 to admit of a satisfactory solution of the inquiry, whether 

 eruptive action is still in progress. This, he then thought — 

 a few years may probably show how far correctly — would re- 

 quire a special delineation and measurement of small areas 

 little affected by lib ration, carried on for years with the most 

 powerful instruments, and, if possible, under a sky such as 

 the North of Europe does not afford. 



It may, at any rate, be admitted that Selenography is not 

 as yet sufficiently advanced to admit of our rejecting as wholly 

 unserviceable any observations made with ordinary care and 

 knowledge of the subject ; and selection can only be practised 

 among an accumulation of materials such as we do not hitherto 

 possess. It is on this ground that I venture to bring forward 

 a few extracts from my own note-books, which may be of some 

 use for the purpose of comparison, or as awakening the curiosity 

 or directing the attention of those who may be commencing 

 lunar inquiries. We shall include the Mare Vaporum and 

 Eratosthenes with our present position, in a very desultory 

 and incomplete study of some of the aspects of this region. 



"1831. April 20. Near Eratosthenes. The level plains and 

 singular dusky tracts S. and S.W. of this crater, when care- 

 fully viewed, exhibited a peculiar stripy appearance, extremely 

 like that of a cloudy sky ; and the effect was quite that of 

 local colour, not unequal surface, since the streaks made only 

 an angle of 10° or 15° with the line of the cusps." The instru- 

 ment employed was an ill-corrected fluid achromatic, on Bar- 

 low's pi-inciple, with an aperture of three inches, and power 

 about 100. 



1855, Oct. 18. The terminator passing through the Sinus 

 JEstuum, this curious effect was again observed with a good 

 3-j\-inch object-glass, as though a brushfull of dark but not 

 evenly-mixed grey colour had been swept over the surface 

 towards E. by S. — The following night, when I of the ring of 

 Copernicus was enlightened beyond the terminator, it was very 

 evident and more extensive — "a vaporous or smoky appear- 

 ance, drawn in stripes or thin parallel bands over mosl of the 

 Mil-face included between Manilms and Copernicus ; its N. limit 



