34^^ Optical Th^cnomen&n 3j> M'oon-Ughi 



my duty to publifli the moft ftriking parts of that work which 

 my memory has enabled me to preferve. It is poffible that 

 among theie obfervations there are forae particulars which 

 require to be rectified : but I Ihall leave to thofe who m.ay be 

 defirous of employing their time on fimilar refearches to exa- 

 mine them with attention, and to increafe the number fo as 

 to form a complete work founded upon fa6ls. 



LVIII. Obfervations on an Optical 'Ph<snomenon produced by 

 Moon-light in ike Vaponrs of the Atmojphere. By ProJeJpjT 

 Wrede*. 



A) 



-BOUT fifteen minutes paft ten at night on the 14th of 

 December iSoo, I obferved above- the horizon of Joachims- 

 thal, in the Ukermark, a very fingular kind of reflection of 

 the rays of the moon's light, and fuch as I had never before 

 obferved. The temperature of the air, in confequence of a 

 thaw, was extremely moderate, and towards the fouth and 

 welt the fky was perfectly ferene, fo that ftars from the firfl 

 to the third magnitude, notwithftanding the great fplendour 

 of the moon's light, could be clearly didinguiflied on the blue 

 ground of the atmofphere. Towards the ealt and north, 

 however, it had a milk white colour, and there appeared 

 near the horizon in the north-ead quarter a few Itreaked 

 clouds, which the common people generally confider as an 

 indication of wind. But thefe as well as the other cloudy 

 parts were fo tranfparent that feveral of the circumpolar flars, 

 luch as the Great and Lcfs Bear,Cepheus, and Caffiopeia, could 

 be obferved. The lower parts of the atmofphere, as well as 

 thofe ftrata in which the above clouds floated, appeared on 

 the firit view to be entirely at relt. The moon feemed to be 

 nearly in the weft-fouth-wefi; quarter, and was fo bright that 

 the fpots of her illuminated fide could be eafily dirtingiiiflied. 

 In regard to her agronomical pofition flie was near the ftar it 

 in the eaftern band of the Fifli, a little to the weft of Mars, 

 and much further from Jupiter. In this pofition fhe was 

 furroundcd by two very eccentric rings, thefmaller of which, 

 being concentric, had the form of an ellipfc; but the larger 

 was circular, as reprefented in the annexed engraving, 

 (Plate V[II.) — ^The principal axis of the ellipfis lay fouth 

 and north, and the conjugate axis eaft and weft. It was 

 interfetled in the former direftion by the eccentric circle, 



• From DiY Gefellfc.haftl^atwjorjchcnder Freunik %u Berlin Nate Hcbriftcn, 

 vol. iii. 1 80 1, 



which 



