192 proceedings: philosophical society 



contributions have been made to the knowledge of the nature of the 

 atom. The discussion of the bearing of these contributions (i.e., the 

 existence of the positive nucleus in the atom as indicated by scatter- 

 ing and deflections of alpha particles by atoms, and the atomic number 

 with its significant bearing on the nuclear charge, as shown by the 

 experiments on the X-ray spectra of the elements and the chemistry 

 of the radio-elements) on the nature of the forces acting between atoms, 

 furnished the main body of the paper. The experimental results in- 

 dicate that the atom is entirely electrical in nature with a highly con- 

 centrated electrically positive nucleus surrounded by neutralising nega- 

 tive electrons. Of these electrons those in the outer layer are active 

 in chemical unions. The possibility that the chemical forces are due 

 to the magnetic fields of electrons revolving in the atoms was shown for 

 several different reasons to be highly improbable. The mode of action 

 of the electrons in binding the atoms was discussed. The electrons 

 were shown to be capable of binding atoms in two ways in the two great 

 classes of chemical compounds, i.e., the compounds showing strong 

 electrolytic dissociation, such as NaCl, and the compounds showing no 

 dissociation, such as the organic compounds and molecules like 2 and 

 N 2 . In the former class there seems to be a complete transfer of the 

 electron from one atom to the other, the atoms being held together by 

 the opposite charges on them due to the transfer. In the latter class 

 the electrons probably lie midway between the two atoms, acting then 

 as actual binding links between them. The two classes of binding 

 merge into one another in compounds of intermediate type. The type 

 of binding taking place between two atoms is governed entirely by the 

 nature of the atoms as given by the periodic system. The bearing of 

 the atomic number and of the periodic system on valency were then dis- 

 cussed. It was shown that according to an idea of J. J. Thomson, 

 which has recently been elaborated by Kosseo, the valency activities 

 of the elements may be explained by the assumption that the atomic 

 number represents the nuclear charge, and that every atom, even at 

 the expense of losing or gaining outer electrons and thus becoming elec- 

 trically charged, attempts to achieve the outer electronic configuration 

 of the inert gas which immediately precedes or follows it. Since the inert 

 gases are assumed to have eight electrons in their outer stable layer, 

 one can explain many regularities found in the periodic table, e.g. why 

 it is that the sum of the negative and positive valencies are equal to 

 eight. To make the facts presented more concrete, the speaker, after 

 having pointed out its weaknesses, adopted the Rutherford saturnian 

 atom with revolving electrons as the most satisfactory model. With 

 this model it was shown by diagrams how, on a theory recently sug- 

 gested by Kossel, various kinds of molecules might be built up from 

 such an atom. 



Mr. F.*R. Bichowsky then spoke on Valence and color. He pointed 

 out that the characteristic feature of chemical union is that the valence 

 electrons are held in equilibrium by forces of attraction and repulsion, 

 both of which are presumably electrical and both of which are due 



