74 



Anniversary Meeting. 



[Nov. 30, 



of energy and on vortex motion and molecular vortices, Sir William 

 Thomson has propounded conceptions which belong to the prima 

 philosophia of physical science, and will assuredly lead the physicist 

 of the future to attempt once more to grapple with those problems 

 concerning the ultimate construction of the material world, which 

 Descartes and Leibnitz attempted to solve, but which have been 

 ignored by most of their successors. 



One Royal Medal has been awarded to Dr. T. Archer Hirst, F.R.S., 

 for his investigations in pure geometry ; and, more particularly, for 

 his researches into the correlation of two planes and into the com- 

 plexes generated by them. 



The other Royal Medal has been awarded to Dr. J. S. Burdon 

 Sanderson, F.R.S., for the eminent services which he has rendered to 

 physiology and pathology ; and, especially, for his researches on the 

 electrical phenomena exhibited by plants, and for his investigations 

 into the relation of minute organisms to disease. 



In making this award, the Council desire not merely to recognise 

 the merit of Dr. Burdon Sanderson's researches, especially those 

 which demonstrate the analogy between the electrical changes which 

 take place in the contractile tissues of plants and those which occur 

 in the like tissues of animals ; but to mark their sense of the important 

 influence which Dr. Sanderson has exerted upon the study of 

 physiology and pathology in this country. 



The Davy Medal has this year been again awarded in duplicate to 

 M. Marcellin Berthelot, Member of the Institute of France, and 

 Foreign Member of the Royal Society, and Professor Julius Thomsen, 

 of Copenhagen. 



The thermo-chemical researches of Berthelot and Thomsen have 

 extended over many years, and have involved an immense amount of 

 work, partly in the application of established methods to new cases, 

 partly in devising new methods and applying them to cases in which 

 the older methods were not applicable. Chemists had identified a 

 vast variety of substances, and had determined the exact composition 

 of nearly all of them, but of the forces which held together the 

 elements of each compound they knew but little. It was known that 

 certain elements combine with one another with great evolution of 

 heat-forming products in which they are firmly united ; while other 

 elements combine but feebly, and with little evolution of heat. But 

 the materials for forming any general theory of the forces of chemical 

 combination were but scanty and imperfect. 



The labours of Messrs. Berthelot and Thomsen have done much 

 towards supplying that want, and they will be of the utmost value for 

 the advancement of chemical science. 



