Light Spots in the Lunar Night. 51 



LIGHT SPOTS IN THE LUNAR NIGHT.— THE CRATER 

 LINNE.— OCCULTATIONS. 



BY THE REV. T. W. WEBB, A.M., F.R.A.S. 



After a long interval, we return to the study of some of the 

 details of the surface of our satellite. In following the arrange- 

 ment of Beer and Miidler we have last described the Lunar 

 Alps (19 in our Index-Map) and should next in order proceed 

 to the W. extremity of the great Mare Imbrium (I) ; but that 

 we ought not to pass without remark the site of a singular 

 luminous appearance described by Schroter with much pre- 

 cision; of which, as might have been expected, no notice 

 whatever has been taken by Beer and Miidler, but which we 

 think of sufficient interest to lay at some length before our 

 readers, together with some other instances of the same 

 nature. 



The earliest mention of any luminosity on the unenlightened 

 part of the moon seems to have been that of Sir W. Herschel, 

 who perceived in 1783 and 1787, three patches of feeble light, 

 which he considered to be volcanoes in eruption. As there was 

 much in favour of the possibility of such an event, and nothing 

 to contravene it, the assertion was generally received. 

 Schroter, who had in 1784 independently noticed with a 4- 

 foot Newtonian, made by Sir W. Herschel, the visibility of the 

 brilliant crater Arisiarchus (43) on the dark side of the moon, 

 and bad perceived that it shone simply by the reflection of the 

 earth-light, was thus induced to make a careful revision of 

 many parts of the unenlightened hemisphere, when sufficiently 

 in front of the earth to receive a considerable share of our 

 reflected rays ; and his attention was especially directed to the 

 neighbourhood of the great wall-plain Flato (38) — a little E. 

 of the district we have last described — by the circumstance 

 that in Jan. 1788, Fischer at Mannheim had perceived a feeble 

 illumination which he had, erroneously as it seems, referred to 

 that region. Schroter had no difficulty in recognizing three 

 phosphorescent spots; measurement and allineation enabled 

 him readily to identify them with the large and very luminous 

 craters Aristarchus (43), Manilius (24), and Menelaus (15) ; * 

 and no reasonable doubt remained that these were the three 

 supposed volcanoes of Herschel. But nothing was perceptible in 

 the vicinity of Plato. In other directions, towards the E. limb 



* B. and M. have preferred, for what reason does not appear, Aristarchus, 

 Copernicus (30), and Kepler (41). The idea of these eruptions, however, was not 

 at once abandoned. Fallows, who died at the Cape in 1831, believed that he had 

 seen them. 



