TRANSACTIONS OF SECTION A. 301 
elements. Now, going back to the region in which hydrogen was situated, one 
was tempted to suggest that this gas was the only known representative of an 
extra short period of three elements. Doubling this number and adding two 
one obtained eight—the number of elements in each of the known short periods. 
Doubling eight and adding two one obtained eighteen—the number of elements 
in each of the long periods, and so on. Although such treatment of the matter 
might appear like playing with figures, it seemed to the speaker of some interest. 
Professor Kerr Grant summarised the difficulty as to the stability of a 
system consisting of one nucieus and one electron. It was difficult, too, to 
account for the non-magnetic character of the hydrogen atom with this struc- 
ture. Magnetism, however, depended probably more on molecular than on 
atomic structure. 
Sir E. Ruruerrorp (replying) said that the chemical inseparability of certain 
isotopes was, indeed, derived from experiments with small quantities, but the 
methods used were very delicate. The separation of Radium D from lead was 
a most important problem; there seems evidence that different leads exist, 
having different atomic weights. The difficulty of stability is common to all 
theories-of the atom; but what it points to is that there is something wrong 
with the theory of electromagnetic radiation—not of the atom. 
The following Paper was then read :— 
On Salts coloured by Cathode Rays. By Professor E. GotpstrEin. 
See Reports, p. 250. 
The following Papers were read in Section A :— 
1. Note on the Magneton as a Scattering Agent of a and B Particles. 
By Professor W. M. Hicks, F.R.S. 
Weiss has proved the existence of elementary magnetic magnets—or their 
equivalent—as a constituent of the atoms of matter. These magnetons should 
act as very effective scatterers of a and @ rays, but the mathematical difficulties 
of a complete discussion of the scattering by a single electron are probably 
extremely great. The particular case where the electrons move in an equatorial 
plane of the magneton admits, however, of a complete mathematical solution, 
and may be useful as throwing some light on the nature of the scattering to be 
expected. It is essentially a question of the orbits of charged particles coming 
from an infinite distance, and in the paper the nature and distribution of these 
are explained. Incidentally also a theory of combined electrons appears. 
2. Demonstration of a Mechanical Analogue of Wireless Telegraphic 
Circuits. By Professor T. R. Lytn, F.R.S. 
3. On the Thermal Conductivity of Air. By Professor T. H. Lay 
and BE. O. Herens. 
4. The General Magnetic Survey of Australia. By EK. Kipson. 
