ASTRONOMY. 



417 



The iucreasiug difficulties in this branch of astronomical discovery 

 are forcibly suggested by the fact that four of these bodies were first 

 taken for planets already known and their non-identity was only estab- 

 lished by later observations. 



l!fumber 253 was discovered while searching for Erigone, and raises 

 the whole number of those found by Palisa to fifty. Use is the forty- 

 third discovered by Professor Peters. 



Of the minor planets discovered in 1884, number 237 has received the 

 name of Ccelestina (erroneously given as Hypatia in last year's report), 

 Number 238 that of Hypatia, 239 Adrastea, 243 Ida, and 244 Sita. Up 

 to February, 1885, there were still 18 which had been observed at only 

 one opposition, excepting, of course, those discovered during the year 

 preceding. 



Ephemerides of the small planets for 1886 will be found in the Ber- 

 liner Astronomisches Jalirhuch for 1888. There are approximate i)laces 

 for every twentieth day, of 247 out of the 253 now kuown, with accu- 

 rately calculated opposition ephemerides for 19 of these. The elements 

 of these first 247 are also glveu. 



MM. Callandreau and Fabry give in the Bulletin Astronomique a set 

 of tables which will be found very useful in computing approximate 

 ephemerides for these small bodies, when the eccentricity of the orbit 

 does not exceed 0-407 (=sin 24o). 



A series of photometric observations of Ceres and Pallas made in 

 April and May, 1885, at Harvard College Observatory gave Ceres =7*71 

 magnitude with a probable error from nine observations of 0*05; Pallas 

 =8-55 magnitude with a probable error of 0-02 from ten observations. 

 Twenty-two observations of Vesta Avere made in 1880-'82, giving the 

 result G*47 as the magnitude of the plant for mean opposition, and the 

 probable error 0'04. Corresponding magnitudes for a distance of unity 

 from tjie sun and from the observer for these three bodies would be 4*27, 

 540, and 3-93, respectively. 



Mr. A. l!il. Skinner, of the United States ISTaval Observatory, has 

 kindly furnished the following complete list of the minor planets. The 

 first list gives the number, name, date of discovery, and the name of 

 the discoverer: the subscript figure to the name of the discoverer is the 

 discoverer's number. The second list is an alphabetical index of the 

 first 252 minor planets. 

 H. Mis. 15 27 



