116 The Rev. Dr. Robinson on the Longitude of the Armagh Observatory. 



ARMAGH OBSERVATORY. 



The correction of the Armagh transit clock on September 21st was = — 

 30'. 45 by a and /3 Lyrae ; f , 7, a and /3 Aquilae ; and a Cygni. 



On Sept. 23rd, by the same stars, It = — 31'.23, and the rate = — 0'.38. 



Hence I derive the following longitudes of Armagh ; each being the mean 

 of those coming and returning : 



