1 873.] Changes in the Moon's Surface. 497 



that no change whatever has taken place in the condition of 

 Linne, and that if any appearances have been presented indi- 

 cating change, such appearances are to be explained either by 

 defective observations, by unfavourable conditions of our own 

 atmosphere, by variations in the angles under which we see 

 lunar objects, or by different incidences of the solar light 

 falling upon them. 



" The results that have as yet been arrived at, and which 

 are supported both by English and Continental observations, 

 are as follows : — 



" First. The existence of a shallow crater, usually pre- 

 senting the appearance of a whitish cloud, which, by the 

 way, is of variable size ; the crater itself has been very 

 rarely seen. Respighi saw it on the 10th of May, 1867, 

 during a perfectly tranquil state of the air. Knott caught a 

 sight of the ring on January 12th, 1867, and, on the 

 same evening, in moments of quiet air and good definition, 

 Buckingham noticed the shallow depression. Webb saw 

 the ring on April nth, 1867. 



" Second. In this shallow crater or depression, a little 

 west of the centre, a small crater with a well-marked 

 interior shadow has been seen more or less distinctly, both 

 in England and on the Continent, since November, 1866 ; 

 in some cases a perfect crater, in others portions only 

 have been detected. The evidence tending to establish the 

 existence of this small crater is certainly beyond dispute. 



" Third. Herr Schmidt, of Athens, carefully observed 

 Linne from October 16th, 1866, and during November, 1866, 

 without having detected either the large shallow crater 

 or the small one within it. The rim of the small crater 

 appears to have first arrested his attention on December 

 13th, 1866, as a delicate white hill ; Buckingham seems to 

 have first seen the shadow as a black spot on the following 

 evening, December 14th. 



" From the data given, a table (see next page) has been 

 constructed. 



" Respighi would seem to have measured the shallow 

 crater instead of the small one." 



Wollf makes the following remarks in the Comptes Rendus 

 for June 17, 1867 : — 



" Since the 10th May I have noticed that the crater Linne* 

 continues to exist, but with a much smaller diameter than 

 that of the crater indicated in the maps of Lohrmann 

 or Beer and Madler. In the centre of the white spot 

 a circular black hole may be seen, bordered on the west by 

 a portion of ground which seems prominent above the 



