594 Sir J. Larmor : Escapements and Quanta. 



one period to another being possible. E qui partition of the 

 whole energy in the molecule between the periods, so far as 

 it may tend to hold good, can only be assisted during 

 encounters or collisions between molecules, when the periodic 

 character of the internal motions is for a brief time suspended. 

 Here, at any rate, fortuitous discontinuous processes inter- 

 vene, in order to establish physical law, in a much coarser 

 manner than a regular automatic escapement mechanism 

 would involve. 



But let us now contemplate an atom differently — after 

 Rutherford's idea — as an outer physical system having its 

 constant periods of free vibration, linked dynamically, — but 

 only to a slight degree so as not much to displace these 

 periods, — to an inner system or core, of more complex 

 elasticity or structure so as not to be restricted to constant 

 periods of its own, and so massive <pr stiff that it can form a 

 receptacle of energy of large capacity, which may be re- 

 plenished from time to time, from colliding ions or other- 

 wise. There is now nothing to prevent this core from gently 

 feeding out the energy, so acquired at each encounter, to 

 sustain the vibrations and other motions of the outer physical- 

 chemical system linked with it, as the blast feeds energy to 

 the sound vibrations in an organ-pipe ? The analogy is 

 rough : but the action, on Helmholtz's exposition, of the 

 vibrating jet of air which blows the pipe, though alternating, 

 need not be discontinuous. 



A new type of vibrating system is thus suggested for 

 general dynamical exploration, possibly fruitful, — namely a 

 periodic system linked by slight continuous coupling with 

 another system of perhaps simple type but not of periodic 

 quality, and of large capacity for energy. 



It has been implied above that the outer (electric) system 

 of periodic quality is of a type which sinks into a configuration 

 free from further loss by radiation, whenever the feed of 

 energy to it fails : indeed, no other type could subsist, but it 

 is the problem of the note here following (p. 595) how such 

 electric types can be possible. 



Finally, a general remark is suggested : that wherever it # 

 proves necessary in physical science to treat of discrete 

 quanta of energy, it may well be that these are packets 

 separated in the cases concerned by the atomic mechanism, — 

 just as period in natural radiation is said in a certain sense 

 to be a creation of the resolving prism or grating, — without 

 having to face the difficult assumption that energy is itself 

 necessarily discrete. The quanta of practical physics would 

 of course be large multiples of such packets. 



