314 Anniversary Meeting. 



The discussion which took place at the recent meeting of the 

 British Association at Liverpool proved that experts still differ as to 

 the exact meaning and causes of the facts these gentlemen have dis- 

 covered. No one, I believe, disputes the theoretical interest which 

 attaches to the researches of both ; or the practical benefits which the 

 Rontgen rays may confer upon mankind as aids to medical and 

 surgical diagnosis. But whatever the final verdict upon such points 

 may be, the two investigators whom we honour to-day have been 

 toilers in a common field, they have both reaped a rich harvest, 

 and it is, therefore, fitting that the Royal Society should bestow upon 

 both of them the Medal which testifies to its appreciation of their 

 work. 



DAVY MEDAL. 

 Professor Henri Moissan. 



The Davy medal is given to Professor Henri Moissan. 



Notwithstanding the abundant occurrence of fluorine in nature, the 

 chemical history of this element and its compounds has until recently 

 been scanty in the extreme, and, as far as the element in the free 

 state is concerned, an entire blank. And yet from its peculiar posi- 

 tion in the system of elements, the acquisition of a more extended 

 knowledge of its chemical properties has always been a desideratum 

 of the greatest scientific interest. 



The frequent attempts which have been made from time to time to 

 clear up its chemical history have been constantly baffled by the 

 extraordinary difficulties with which the investigation of this element 

 is beset. 



Thanks to the arduous and continuous labours of M. Moissan, this 

 void has been filled up. He has effected the isolation of fluorine in a 

 state of purity, and prepared new and important compounds, the 

 study of which has placed our knowledge of the chemical and 

 physical properties of this element on a level with that of its imme- 

 diate allies. 



During the last few years M. Moissan has turned his attention to 

 the study of chemical energy at extremely high temperatures, and by 

 the aid of the electric furnace, which he has contrived, he has 

 succeeded in obtaining a large number of substances whose very 

 existence was hitherto undreamt of. It is impossible to set bounds 

 to the new field of research which has thus been opened out. The 

 electric furnace of M. Moissan has now become the most powerful 

 synthetical and analytical engine in the laboratory of the chemist. 



On studying the accounts which Moissan has given of his re- 

 searches, we cannot fail to be struck with the originality, care, perse- 

 verance and fertility of resource with which they have been carried 



