204 



Mr. W. Sutherland on Molecular 



round the axis of electrization. If we imagine the axes of 

 magnetization and of rotation in the Earth to coincide, it 

 will furnish a large mechanical model of the pair of electrons, 

 magnetization replacing electrization. The pair of electrons 

 is a gyrostat electrized parallel to the axis of rotation. The 

 electrons of a pair do not move round one another in a plane, 

 but each may be treated on the averageas moving in a plane at 

 right angles to the axis of electrization. The figure illustrates 

 the conception. PN is the axis of electrization, the positive 



Tier. 3. 



electron moving in a circle round P as centre in the direction 

 shown by an arrow, and the negative electron round N. 

 The components of the attraction between # and \> along 

 P# and Nfc> keep # and \> in their circular orbits, while the 

 components of the attraction along NP equilibrate the forces 

 acting on # and \} on account of the electric field of the 

 whole molecule parallel to NP. The length of NP is a. 

 Other rotational motions of these electric gyrostats may have 

 to be considered in other connexions, but at present the 

 motion postulated suffices. The independence of electric 

 moment in the molecules of the element gases both of tem- 

 perature and density indicates that P# and Np are small 

 compared with NP, and that the rotatory energy of a pair 

 of electrons is a constant like its electric moment. Probably 

 the same statements apply to compounds, the change associated 

 with the replacing of v in the attractional virial hj v + k 

 being probably apparent rather than real. Imagine an 

 element gas so compressed that there is no gap between 

 molecule and molecule, the whole mass being a uniform 

 collection of pairs of electrons at distance r 2 apart, each pair 

 having an electric moment e<j Y proportional to r x . Imagine 



