1881.] Dr J, B. Pearson, On the Constellation Ursa Major. 93 



May 9, 1881. 

 Professor Newton, President, in the Chair. 



E. J. Sing, B.A., Christ's College, and R. I. Lynch, Curator of 

 the Botanic Garden, were balloted for and duly elected associates 

 of the Society. 



The following communications were made to the Society : 



(1) On the probable secular change in the position and aspect 

 of the Constellation Ursa Major. By J. B. Pearson, D.D. 



In the Homeric Poems, which without prejudice may fairly be 

 fixed about 750 B.C., this constellation is spoken of as distinctly 

 circumpolar: 



olw 8' a/j,fiop6<> icTTt Xoerpcov 'tl/ceavolo. 



Iliad, t. 489, Odyss. E. 275. 



Now the latitude of Alexandria, practically the most southern 

 point that could have been visited at that era by Greek navigators, 

 being about 31° 10': any star, to be circumpolar there, must be in 

 about 58|° north declination. At the present time, only one of the 

 seven chief stars ol the constellation Ursa Major is so, being in 

 N. Dec. 60° 26' : the rest being less, and one so low as 49° 57'. 

 If however we employ the method of computation indicated in 

 a former paper (Proc. Vol. hi. p. 70, &c), viz. find the present 

 Latitude and Longitude of each separate star ; subtract from the 

 Longitude an amount proportional to the annual precession of 

 50" - 1 continued during a period of about 2600 years, and then 

 find the R. A. and Dec. of each star at the commencement of 

 the period, we shall find that the star w, the one with the least 

 North Dec, was then in N. Dec. 64°, /3 and y between 67° and 68°, 

 8, e, £ 70° to 71° and a nearly 73°. Clearly in those days the con- 

 stellation fulfilled the conditions of the Homeric verse in a very 

 different way to what it does now. I may as well mention that 

 the two pointers are a and /3, and v the star at the other extremity 

 of the constellation. 



The annexed Table indicates the present positions of the 

 several stars, and also what they would have been in 750 B.C. and 

 ad. 1; the upper line obviously answering to the first, and the 

 lower to the second date : 



