The Moon. 203 



been here brought forward may appear of trifling interest, but 

 as there is reason to believe that selenography is now receiving 

 a powerful impulse, it may be useful to the student to know 

 what difficulties and uncertainties may attend his own path, 

 and what has, or has not, been done to remove them. He will 

 not regret having made acquaintance with them at his first 

 essay. 



We must not omit some other curious observations which 

 include a more extended range. Such was that of Schroter, 

 who upon one ocasion, when the moon was 2d. 23h. old, found 

 the whole W. portion of the C( Mare " unusually bright, and 

 of a yellowish hue, so as scarcely to be distinguished from its 

 mountain border ; this appearance, unprecedented here, or in 

 any similar level, fading away entirely into the ordinary grey on 

 the opposite side of the plain. At another time, the moon's age 

 being 6d. 7h., he saw " an incredible, innumerable multitude" of 

 bright specks in the grey surface, chiefly in places where no 

 known object existed. A subsequent examination of other 

 grey plains, under a similar incidence of light, showed him 

 nothing equally remarkable. More than two years afterwards, 

 however, under a very different and almost vertical illumination, 

 the moon being lid. 19h. old, the scene was renewed; the 

 plain was so interwoven and variegated, like the veins of an 

 animal, or an irregular tissue, with streaks of light, and 

 actually innumerable bright points, that it would have been 

 difficult for the most skilful artist to give a sufficiently striking 

 representation of such a magnificent scene. Two days after- 

 wards this beautiful effect had disappeared, and nothing of the 

 kind could be traced in the Mare Serenitatis on the neighbour- 

 ing levels, where the sun had by that time attained a corres- 

 sponding elevation.* No other similar instance was ever 

 recorded by him ; but the following from B. and M. (who 

 characteristically ignore what he has described) was evi- 

 dently one of the same nature. The moon being between 

 lOd. and lid. old, they noticed that the greater part of a white 

 streak which runs from Prod us (No. 12 in the Index-Map) 

 towards Vicar A B was resolved, through an area of 230 miles by 

 28, into fully 150 points of light, like a jet of water dispersed 

 into spray — the whole plain appearing also more speckled than 

 usual. I was once (1832, July 4) so fortunate as to witness 

 something of the kind, about the time of first quarter, when the 

 whole plain, notwithstanding the imperfection of my instru- 

 ment — a fluid achromatic of four inches, upon Barlow's plan — 

 was seen beautifully mottled with light and shade, a spot at the 

 N. extremity nearly rivalling the brightness of Prochis. It is 



* But from which the rays would be reflected at a very different angle to tho 

 spectator — a circumstance which Schroter does not notice. 



