Note 10 — Chapter VII · AURORA-LIKE PATCHES ON THE PARTIALLY-ECLIPSED MOON.

This observation is not without a certain amount of confirmation by more recent ones, in which certain lunar objects and regions have been suspected of mist or vapour. Mr. Birt (‘English Mechanic,’ vol. xxviii. no. 725) mentions two—the cloud-like appearance of the white patch west of Picard, and the interior of Tycho, which at one time always misty and ill-defined, is now become perfectly distinct and sharply defined.

December 4, 1878, 4h 45m. I observed Klein’s crater as a dull dark spot, larger than the true object; and while definition was good and other objects were well defined, “the floor of Klein’s object, the oval spot near, and also Agrippa (especially), all had an odd misty look as if vapour were in or about them” (‘English Mechanic,’ vol. xxviii. no. 727). The mystery of different observers seeing and not seeing Klein’s object on the same night is hardly to be accounted for by the angle of illumination.