ANNUAL ADDRESS OF THE PRESIDENT. XLIX 
the analogy of chemical properties, but also the similarity of physi- 
cal forms;”* the discoveries in electrolysis, with their bearing on 
atomicity, as published by Faraday in 1834, in the Seventh Series or 
his Experimental Researches ; + the labors of Berzelius in clarify- 
ing the atomic weights of the elements; the “law of Octavyes,” an- 
nounced by Newlands in 1865, according to which the elements were 
divided into groups, having numbers differing by seven, or some 
multiple of seven ;{ the enlarged Periodic System of the elements, 
as published by Mendelejeff in 1869, with the prognostication of 
undiscovered metals required to make the system complete—among 
them a metal which the Russian chemist proceeded to namé “ekaalu- 
minium” in advance of its discovery ;§ the discovery of the missing 
metal in 1875, by Lecoq de Boisbaudran, who found it in a blende 
from the mines of Pierrefitte, in the Pyrenees, and gave to it the 
name of “Gallium,” without knowing that he had lighted on the 
“missing link” of Mendelejeff; || the extension of this periodic 
system by Lothar Meyer, with his Curve of the Elements, showing 
that the ductility, fusibility, and volatility of bodies are functions 
of their comparative atomic weights; the periodic system, as re- 
vised and extended during this very year, by Prof. Carnelley, in the 
light of the experimental boiling and melting points and heats of 
formation of the halogen compounds of the elements,§] (chlorides, 
bromides, and iodides;) Carnelley’s tables of color relations in 
chemical compounds as indicating the influence of atomic weights ;** 
and, lastly, Carnelley’s new reduction of the periodic system of the 
elements considered in the light of their occurrence in nature, with 
the helpful inferences to be drawn from it ***—these, and such like 
discoveries as these, following in the wake of the modern atomic 
-* Experimental Researches in Electricity, vol. I, pp. 230-258. 
+ Wurtz: The Atomic Theory, p. 58. 
t+ Newlands: The Discovery of the Periodic Law, &c., p. 14. 
3 Annalen der Chemie und Pharmacie, Supplement Band 8, p. 133 et seq. 
|| Comptes Rendus, t. LX X XI, p. 493. How fully Mendelejeff recognized 
in gallium the characters wanted to fill the gap in his periodic system, see 
Comptes Rendus, same volume, p. 969. 
{| Philosophical Magazine for July, 1884. 
** Phil. Mag. for August, 1884. 
*** Phil. Mag. for September, 1884 
18 
