500 Changes in the Moon's Surface. [October, 



time. The following description is from Mr. Browning's 

 Note-Book. I invite special attention to the times of 

 observation : — 



"Septembers, 1869. 11.30 a.m. — Saw Linne very dis- 

 tinctly as a crater, elongated north and south. The north 

 part of the crater the narrowest. The evening terminator 

 crossing Bessel. Eye-piece used, positive achromatic, 

 power 208. 



" 2.15 a.m. — The wall of the crater appears nearly per- 

 pendicular on the west. 



" 3 a.m. — The small crater is seen to be in the centre of 

 a shallow cup, about four or five times its own diameter. 

 Eye-piece same kind, power 306. 



" 4 a.m. — A white nebulous line, resembling steam, 

 appears to start from the mouth of the crater, and is con- 

 tinued in the form of a scythe, with the blade directed 

 towards the west. At 4.15 this line was much fainter, and 

 at 4.50 it was no longer visible. As this appearance only 

 presented itself for about ten minutes, I have little doubt 

 that it was an optical illusion, caused by a small cloud 

 in our atmosphere, moisture in front of the pupil of the eye, 

 or some cause quite independent of the object." (I venture 

 to doubt whether any such cause could have produced 

 an illusion of the sort lasting for so many minutes). 

 " During the time the appearance lasted," proceeds Mr. 

 Browning, " I changed the eye-piece, and rotated the 

 drawer-tube which carried the eye-pieces. As neither of 

 these proceedings affected the appearance, it could not have 

 been a * ghost,' caused by reflection from the surface of one 

 of the lenses in the eye-piece." 



Mr. Browning, after considering the evidence afforded by 

 his own observations, considered in connection with those 

 made by others, arrives at the conclusion that " there is 

 scarcely any ground for supposing that any change has 

 occurred in this small but celebrated crater. Should this 

 eventually prove to be the case," he adds, " the time that 

 has been given to this matter has not on that account been 

 lost. Attentive examination of this minute object has 

 made us acquainted with peculiarities of the reflecting 

 power of portions of the moon's surface which may ulti- 

 mately lead to some more exact knowledge of the character 

 of the surface of our most, interesting because most per- 

 plexing satellite." 



These remarks appear to me to contain the gist of the 

 whole matter. We see that Linne has a surface so consti- 

 tuted that as the sun is rising there, and so pouring his rays 



