34 * 4 ? Mr. Schroeter’s Observations 
effect of the immediate solar light, probably illuminating some 
prominent, flat area, as yet situated in the dark hemisphere. 
Thus far the observations: and now for the application of 
them. 
I need hardly insist upon the proofs, that the very faint pyra- 
midal glimmering light, observed on the 24th of February, at 
the extremities of both cusps, could by no means be the imme- 
diate effect of the solar light, all the circumstances of the ob- 
servations militating uniformly and decidedly against this 
supposition, which, were it true, would oblige us to admit a 
most unaccountable diminution of light, and thence also a 
density of the lunar atmosphere, that ought to exceed even 
the density of ours; a fact absolutely contradicted by all the 
lunar observations hitherto made. This light, indeed, was so 
very faint, that it disappeared at 7 h 20', when the moon ap- 
proached the horizon ; whilst, on the other hand, Aristarchus, 
which had no light but what it received from the earth, was 
still very distinguishable ; and the summit of Leibnitz /, fig. 1, 
(which, though far within the dark hemisphere, was, however r 
illuminated by the immediate solar rays) displayed a degree of 
brightness which, although when compared with that of the 
cusp d ef, it appeared very faint and dwindling, equalled, how- 
ever, that of our Pic of Teneriffe. Nor can it be conceived 
why this glimmering light broke off so suddenly at both the 
cusps, without a progressive diminution. It can hardly be 
supposed that similar, grey, prominent, flat areas, of the same 
form and dimensions, and comparatively of a faint light, which, 
whilst in the dark hemisphere, they derive immediately from 
the sun, exist on all parts of the moon; more especially as at 
the places observed, the limb happened to exhibit throughout 
