212 



ASTRONOMY. 



Frigga (77) was refouud by Peters on July 17, 1879, after having been 

 at large for several years. Prof. Peters suggests that Frigga may be 

 variable. 



The discoveries for 1880 were : 



Date. 



No. 



Xame. 



Discoverer, 



1880. 

 February 6 

 February 17 

 March 1 - 

 April 7 - - 

 April 10 - 

 August 30- 

 September 4 

 September 30 



212 

 213 

 214 

 215 

 216 

 217 

 218 

 219 



Lilaea - 

 Oenone 



Palisa. 



Peters.* 



Palisa. 



Knorre. 



Palisa. 



CosKia. 



Palisa. 

 Palisa. t 



"• His 4l8t discovery. 



t His 28tli discovery. 



The Jalirhuch for 1882 gives some details regarding the first 173 as- 

 teroids, which we condense as follows : Out of these 173, there are 120 

 which have been satisfactorily observed at 5 (or more) oppositions, 11 

 which have been observed at 4 oppositions, 10 at 3, 14 at 2, and 18 at 1 

 only. Of these last 18, some are new discoveries and only _DiA'(?(BoRELLY), 

 and Scylla (Pax,isa) are yet to be rediscovered. Jueica (Watson) has 

 been lately found, after having been lost six years. 



The Moon. — The lunar photographs taken with the 13-inch reflector at 

 the University Observatory, Oxford, have been utilized for finding a 

 new value for the semi- diameter of the Moon. The process adopted was 

 very nearly the same as that employed by Wichman, and the resulting 

 mean semi-diameter is 15' 34" .175 + 0".069. Mr. Neison has, from a 

 careful discussion of nearly 1,100 observations, made at Greenwich, Ox- 

 ford (Kadcliffe), and Washington, deduced the value — 



15' 33".37+4".10-r(l + 0".70 x aperture in inches). 



This empirical formuUi, he adds, agrees closely with the theoretical 

 formula, founded on the assumpution that the differences between the 

 semi-diameters obtained with instruments of different aperture vary as 

 the diffraction discs and the amount of light. Ai^plyingthe formula to 

 a 13-iuch reflector, and adding the photographic irradiation, which Mr. 

 Nieson states his experiments indicate to be about -f 0".3, the photo- 

 graphic semi-diameter should be 15' 34" .08. 



!N^o papers on the Moon published during the past year exceed in im- 

 portance those by Mr. G. H. Darwin on the secular eifects of tidal fric- 

 tion on the configuration of a planet and its satellite. In the first paper 

 the theory of the deformation of a viscous or imi^erfectly elastic spheroid 

 under the attraction of satellites is investigated. Kumericitl calculations 

 show that bodily tides in the Earth are at present very small. From this 

 point ]\rr. Darwin was led to consider the perturbed rotation of such 

 a spheroid, and the reaction on the perturbing bodies. He has in 

 the A. K. 2294 given the following summary of the results arrived at 



