1919] on Ether and Matter 467 



and this is approximately and roughly what the K L M series of 

 spectrum lines correspond to — with some exceptions. 



When a cataclysm occurs and an electron is expelled, it is expelled 

 as I think with the velocity which it possessed in the atom just before 

 it burst its bonds and flew off. For the energy required to fling a 

 planet to infinity, under an inverse-square law, is just double the 

 energy with which it was already moving in its circular orbit. Its 

 own orbital energy is therefore the quantum of energy that has to be 

 supplied in order to get a satisfactory ejection. Some of it might be 

 supplied by the falling in of other particles from their original orbits : 

 for their kinetic energy therein would be inversely as the distance 

 from the nucleus. Hence if K, L, M orbits have the radii 1, 4, 9, 

 three units of L energy would represent the fall from L to K, and 

 this added to the original L energy would give the quadruple L 

 energy which is equal to the K energy, and able to eject a K particle. 

 Similarly a ninefold multiple of the M energy, eight units of which 

 would be acquired by falling to K, would supply that particle with 

 the ejection energy, equally well. 



Would an M particle falling to L be able to eject an L particle ? 

 1 - -i = /^ of a K unit of energy would be acquired in the fall from 

 M to L, that is f M units, so altogether | of M energy would be 

 transmitted, and that, being equal to a unit of L energy, ought to be 

 sufficient. 



Hence, in general, particles may be ejected from any ring, either 

 by direct impact from outside, or by accumulated disturbance of 

 X-rays, or by a collapse of particles from one orbit to the next ; and 

 from an immense group of atoms, as in a visible speck of substance, 

 all kinds of radiation can be emitted simultaneously. 



Are we to suppose that there is only one electron in each orbit, or 

 may several of them distribute themselves over a ring in accordance 

 with some law of stability ? Both alternatives are possible, and both 

 are likely to be found in nature. It seems hai'dly Hkely that a uranium 

 atom should possess 92 different orbits, although it does contain 92 

 electrons. Yet even this number of orbits is possible within the 

 dimensions of an atom. We need not exclude the possibility, as 

 taking up too much room. For given the size of the ultra-innermost 

 or J orbit as 1, the outer orbit would, on Bohr's law pressed to 

 extremes, be (92)^ times that radius, say 8464 times the size of the 

 innermost orbit ; but if this innermost orbit is near the uranium 

 nucleus, which may be 4/92, or say 5 times the radius of the hydrogen 

 nucleus, the boundary or confine of the atom is some 10,000 times as 

 far away ; leaving therefore just room enough for the 92 Bohr orbits, 

 though not much more than is required. 



Hence if there were any reason to desire them separate, they 

 30uid be made room for, without endowing the atom with outlying 

 or ever-ready electrons likely to confer upon it very active chemical 

 properties. But so far as I see, so many separate orbits are not 



