PRESIDENTIAL ADDRESS. 15 



He propounds the idea that non-metals are bodies which 

 have a strong affinity for electrons, while metals are bodies 

 with but slight affinity, and thus indicates the phenomenon 

 of predisposing affinity. To the electron he assigns the 

 symbol "E" and the hypothesis is thus summed up: — 

 " Electrons are atoms of the chemical element, electricity; 

 they possess mass; they form compounds with other 

 elements; they are known in the free state, that is, as 

 molecules; they serve as "bonds of union" between atom 

 and atom, and the simple equation that symbolises the 

 union of sodium and chlorine should henceforth be written 

 as E Na + 01 = Na E 01. Sir William Ramsay thus sum- 

 marises his arguments for the disintegration or breaking 

 down of the elements : — 



"The conversion of an atom into an ion by gain or loss of an 

 electron completely changes the property of the element. Certain 

 elements, termed radio-active, are losing electrons and changing 

 into other forms of matter which have equal claims to be considered 

 elementary. Under the influence of ultra-violet light many metals 

 (tin, etc.) lose electrons, but no proof exists that they yield other 

 elemental forms. Loss of electrons is coincident with an enormous 

 evolution of energy in a concentrated form, so that probably 

 change from one elemental form to another will be manifested, 

 like chemical change, by gain or loss of energy. The irregularity 

 of the numbers representing the atomic weights can be represented 

 on the hypothesis that the addition or subtraction of definite 

 groups of electrons is the cause of their divergence from a perfectly 

 regular series." 



Prout in 1815 advanced the theory of a fundamental basis 

 of matter called ' protyl,' of which all the elements are but 

 modifications, and that the numbers we call atomic weights 

 are multiples of hydrogen, and should therefore be expres- 

 sible by whole numbers. Egerton in February last published 

 a research which Sir William Ramsay describes as an epoch 

 making paper, which briefly put is as follows: — The atomic 



