1894.] President's Address. 53 



disposal was only about 1 gram, but with this small quantity he 

 determined the atomic weight of the element, and ascertained the 

 characters of its salts with such precision as to leave no doubt of the 

 identity of scandium with the element Ekabor, the existence of which 

 was predicted by Mendeleef, in the memorable paper in which he 

 first enunciated the Law of Periodicity. 'Cleve's research, indeed, 

 constitutes one of the most brilliant proofs of the soundness of the 

 great generalisation which science owes to the Russian chemist. 



A not less remarkable instance of Cleve'a skill as a worker is seen 

 in his research on samarium and its compounds, which he communi- 

 cated, as one of its Honorary Foreign Fellows, to the Chemical Society 

 of London. The existence of samarium was inferred independently by 

 Delafontaine and Lecoq de Boisbaudran, but we owe to Cleve the 

 first comprehensive investigation of its characters and chemical 

 relations. From the nature of its compounds, a large number of 

 which were first prepared and quantitatively analysed by Cleve, and 

 from the value of its atomic weight, which was first definitely estab- 

 lished by him, it wo aid appear that samarium most probably fills a 

 gap in the eighth group of Mendeleef 's system. 



We are further indebted to Cleve for a series of determinations of 

 the atomic weights of the rare substances yttrium, lanthanum, and 

 didymium; these are generally accepted as among the best authenti- 

 cated values for these particular bodies. 



No record of Cleve's scientific activity would be complete without 

 some reference to his investigations in the domain of organic 

 chemistry, and more particularly to his studies, extending over 

 twenty years, of naphthalene derivatives. By these researches, 

 made partly independently, and partly in conjunction with his pupils, 

 among whom may be named Atterberg, Widman, Forsling, and 

 Hellstrom, Cleve has gradually brought order out of confusion, and 

 has supplied most valuable experimental evidence of the constitution 

 of naphthalene, and of the course of substitution of naphthalene 

 derivatives. Within recent years a score of workers have occupied 

 themselves with the same field of research, and no greater proof of 

 Cleve's accuracy and care as an investigator could be furnished than 

 the manner in which his naphthalene work confessedly one of the 

 most intricate and complicated sections of the chemistry of aromatic 

 compounds has stood the ordeal of revision. 



DARWIN MEDAL. 

 Et. Hon. T. H. Huxley, F.B.S. 



The Darwin Medal is awarded to Thomas Henry Huxley. 



Of Mr. Huxley's general labours in biological and geological 



