Discoyitinuity in the Phenomena of Radiation 73 



To meet this difficulty two courses seem immediately 

 possible, one is to abandon the principle of equipartition, but 

 still retain the classical dynamical principles and discover the 

 flaws in the chain of inference which leads from the latter to 

 the former. Such a course is perfectly logical, and finds favour 

 among the older and more conservative of physicists. But on 

 the whole, opinion seems to be turaing generally to a more 

 drastic solution, to a detn'al of the complete validity of Newtonian 

 Dynamics itself. It must be confessed that it is not only on 

 these matters that the foundations of classical dynamics have 

 shown signs of being no longer able to support the superstructure 

 of our knowledge, and of requiring something broader still to rest 

 on. It is not surprising that in this particular difficulty attempts 

 are being made to arrive at a set of principles of Avider application 

 than any contemplated by Newton or his immediate followers. 

 To the treatment of the movements of our solar system and of 

 bodies of ordinary dimensions on the earth's surface, the 

 Newtonian dynamics has shewn itself admirably adapted, although 

 there are one or two minute discrepancies which have obstinately 

 resisted explanation. 



When we pass into the region of molecular, atomic and 

 electronic motion and the transference of energy from such 

 exiguous bodies to the ether, we are dealing with orders of mag 

 nitude far removed from those contemplated in gravitational 

 theory. Bodies of excessively minute dimensions but possessed 

 of enormous speeds are our material. The 30 kilometres per 

 second or so of our earth's motion round the sun is a very snail's 

 pace compared to the speed of electronic movement with which 

 we are now-a-days familiar, attaining in some cases almost to the 

 speed of light, 300,000 kilometres per second. There is little to 

 marvel at, if it should turn out that we want new laws to 

 co-ordinate the new knowledge in regions so remote from our 

 customary perceptions, laws to which Newton's principles consti- 

 tute an excellent approximation under the conditions for which 

 they were designed. 



