Neighbourhood of the Lunar Spot, Mare Grisium. 361 



dered at if they were to consider this " all moonshine/' nor 

 would a closer acquaintance with the author increase their con- 

 fidence in his judgment. But he had a very fine eye, and there 

 may be hints here not to be despised. As to the general 

 question of vegetation, no doubt a flora like our own could not 

 exist under such very adverse conditions. But this would 

 furnish no argument against the possibility of one adapted to 

 its peculiar situation, and we must not omit to mention that 

 one of our first authorities on this point, De la Rue, is inclined 

 to favour such an idea from the circumstance that in the course 

 of his photographic investigations he has found that parts of 

 the moon, equal in apparent brightness, are by no means equal 

 in actinic energy. This indicates the presence, in certain 

 situations, of rays not otherwise manifested, which are inca- 

 pable of producing a photographic effect — such a result as 

 might naturally be expected if those portions of the surface 

 were clothed with vegetation. 



I have been repeatedly struck with the very singular aspect 

 of this region under a high illumination, in its uncommon con- 

 tour and sharply -defined intermixture of light and darkness ; . 

 and I venture to think that a very careful study of it might 

 probably be in some way ultimately rewarded. We have not, 

 as far as I am aware, a single representation made on an ade- 

 quate scale, and with sufficient accuracy, of the appearance of 

 this district in the full moon, and the attempted delineation of 

 B. and M. is scarcely so successful as the rough but charac- 

 teristic draught given by old Hevelius, of what he calls his 

 " Paludes Amarae." This is in fact not surprising. The object 

 of Beer and Madler, as of Lohrmann before them, having been 

 the delineation of the elevations and depressions of the surface, 

 any adequate representation of those varied tones of grey and 

 white, to which the term "local colour" may be conveniently 

 though not very correctly applied, and which are so strangely 

 unconformable with the actual relief, would have been a simplo 

 impossibility. Hitherto the attention of selenographers has 

 been, naturally enough, much more directed to the very intel- 

 ligible relief than to the intricate and perplexing shadowing of 

 the surface ; and hence we do not as yet possess either special 

 topographical delineations, or a general map of the full moon, 

 at all corresponding with the present requirements of science.* 

 A general chart would demand a great expenditure of time and 

 labour, especially if the gradations of light are accurately repre- 

 sented, without which it would be of little service ; but careful 

 drawings of separate spots might be very advantageously un- 



* Russell's, fifteen inches in diameter, published about 1797, is the best that I 

 have seen, but it is rather a spirited sketch than a faithful likeness. 



