1911.] Anniversary Address by Sir A. Geikie. 443 



meteoric swarms, and (in the domain of the more classical astronomy) on 

 periodic orbits. 



Sir George Darwin's ' Collected Papers ' have now been published in four 

 volumes by the Cambridge University Press. They form a monument of 

 •analytical skill and power devoted persistently through a long series of 

 years to the elucidation of a definite series of questions of the highest 

 interest. The difficulties of the tasks to which he has addressed himself 

 are enormous ; but, although some of the conclusions only claim as yet to be 

 provisional and speculative, a mass of definite achievement remains which 

 will always rank as one of the most substantial contributions to the study of 

 •cosmic evolution. 



Eoyal Medals. 



The assent of His Majesty the King has been signified to the following 

 awards of the two Eoyal Medals : — 



The Eoyal Medal on the physical side was assigned to Prof. George 

 Chrystal, of Edinburgh University, on account of his contributions to 

 mathematical and physical science, especially, of late years, to the study 

 of seiches on lakes. Conspicuous in his early years as one of Clerk 

 Maxwell's principal lieutenants, it is to him that we owe the experimental 

 proof of the extreme precision of Ohm's law of electric conduction (' Brit. 

 Assoc. Eeport,' 1876). His memoir on the differential telephone ('Trans. 

 Eoy. Soc. Edin.,' 1880) was a notable early extension of the theory and 

 practice of Maxwell's principles as regards inductances, now become more 

 familiar when power transmission, as well as telephonic intercourse, proceeds 

 by use of alternating currents. His duties as a teacher of mathematics led 

 to the ' Treatise on Algebra,' which, besides being a book of original vein, 

 was the earliest systematic exposition in our language of the more rigorous 

 methods demanded in recent times in algebraic analysis. But this purely 

 mental discipline, and its continuation in various memoirs on abstract 

 mathematics, could not wholly occupy a mind trained originally in the 

 school of physical science. Of late years Prof. Chrystal has been engaged 

 with great success in a most interesting subject of research, in the theory 

 and the observation of the free persisting oscillations of level in lakes, 

 first observed and analysed by Forel on the Lake of Geneva. By this work 

 he has, on the one hand, added a new interest to the scenery and the 

 physical geography of the Highlands, and, on the other hand, has extended 

 the domain of the exact application of the principles of mathematical 

 hydrodynamics. 



At the moment when the Council was adjudicating this Medal it was 

 unaware that the illustrious mathematician at Edinburgh was then lying on 



