296 [Dec. 1 



skilfully in this catalogue are of the highest value. The stars ob- 

 served are almost entirely those observed by Bradley, and the com- 

 parison of the observed places gives a great addition to our knowledge 

 of the proper motions of the fixed stars, and thus forms an enlarged 

 basis for our deductions respecting the proper motion of our system 

 in space. 



Dr. Robinson gives a separate catalogue of the proper motions 

 which he considers to be established by the comparison above men- 

 tioned. 



The duties of the observatory and the preparation of the above- 

 mentioned catalogue have not prevented Dr. Robinson from devoting a 

 large amount of attention to physical research; as will be seen from his 

 papers on the Lifting Power of an Electro-magnet, published in the 

 f Transactions of the Royal Irish Academy,' which contain the results 

 of careful quantitative experiments extending, as far as other avoca- 

 tions permitted, over a period of about ten years ; those on the curious 

 subject of the Stratification of the Electric Discharge, published in the 

 ' Proceedings ' of the same Academy ; and more recently an elaborate 

 paper " On Spectra of Electric Light, as modified by the Nature of 

 the Electrodes and the Media of Discharge," presented to the Royal 

 Society on the 1 9th of last June, and since ordered to be printed in 

 the ' Philosophical Transactions.' This last paper contains the results 

 of careful measures of the angular position of the bright lines observed 

 in no less than 173 spectra. The results would seem to indicate 

 that in this branch of physics, which has recently excited a great 

 deal of attention, overhasty generalizations have in some cases been 

 made ; but however that may be, the data collected in this paper 

 can hardly fail to be of high importance in the event of any theory 

 being propounded to account for the positions and variations of 

 brightness of the lines. 



PROFESSOR STOKES, 



In presenting you with this Medal to be transmitted to Dr. 

 Robinson, I may express the regret of the Royal Society that he 

 should have been prevented by indisposition from attending person- 

 ally to receive our congratulations on the accomplishment of the 

 great work on which he has expended so vast an amount of labour ; 

 and our assurance of the warm welcome with which the Society will 



