1862.] 295 



The Council have awarded a Royal Medal to the Rev. Dr. Thomas 

 Romney Robinson, F.R.S., of Armagh, for the Armagh Catalogue 

 of 5345 Stars, deduced from observations made at the Armagh 

 Observatory, from the year 1828 up to 1854 ; for his papers on the 

 Construction of Astronomical Instruments, in the ' Memoirs of the 

 Astronomical Society ;' and his paper on Electro-magnets, in the 

 ' Transactions of the Royal Irish Academy.' 



In various papers published in the ' Transactions of the Royal Irish 

 Academy,' and in the ' Memoirs of the Royal Astronomical Society,' 

 Dr. Robinson long since showed that he had profoundly studied the 

 use as well as the mechanical construction of astronomical instru- 

 ments, the various errors to which they are liable, and the best 

 methods of discovering and eliminating them ; and he proved him- 

 self to be fertile in ingenious suggestions for the improvement of 

 instruments. 



It is not, however, necessary to dwell further on these papers, 

 as the Medal is more especially awarded for the Armagh Cata- 

 logue of the places of 5345 Stars, deduced from observations 

 made at the Armagh Observatory between 1828 and 1854. This 

 work has recently been published on the recommendation of the 

 Royal Society by the aid of the annual Government Grant. Most of 

 the stars have been observed five times, both in Right Ascension and 

 North Polar Distance, with the Transit Instrument and Mural Circle 

 respectively. No one who has not gone through some work of the 

 same kind can imagine the vast amount of labour which the reduction 

 of such a mass of observations requires. The individual results from 

 each observation are given, so that we can form an accurate idea of 

 the precision finally attained. Dr. Robinson has spared no pains to 

 study the errors of all kinds of the individual instruments employed, 

 either to correct them or to make the due allowance for them. Thus 

 he examines the divisions of the mural circle by help of twelve micro- 

 scopes, though only four are used in taking the actual observations. 

 The effect of the variation of atmospheric density on the rate of the 

 transit clock is compensated by a suitably adjusted barometer form- 

 ing part of the pendulum. The true cylindricity of the pivots, both 

 of the transit and the mural circle, is ensured by the method, intro- 

 duced by him, of using a diamond point in the turning. 



The materials which have been accumulated so laboriously and so 



