362 RADIATION OF ENERGY. 



maxima from the characteristic line was of the value that would be expected on 



this theory. 



Notwithstanding the fact that Einstein's theory can be used to explain these 



experimental results, I do not think that his light-quantum hypothesis is admissi- 

 ble. From my point of view energy has no existence independently of matter, 

 and therefore certainly cannot be propagated through space, apart from matter, 

 in discrete quantities. It appears to me, however, to be quite possible that the 

 experimental results just described may be explained on Planck's quantum hy- 

 pothesis which involves the disappearance of energy from matter in discrete 



quantities. 



Lorentz 1 has indicated very clearly the difficulties and absurdities into which 



the light-quantum hypothesis would lead us. For instance, he shows that since 



2 million interference maxima can be obtained for yellow light, a quantum must 



in some cases be at least a meter long. Also to fulfil the requirements of the 



theory of diffraction for optical instruments it must be as wide as the objective 



of our largest telescope. Consequently, under certain circumstances, the 



quantum would be quite bulky ! 



Finally, the question arises does Planck's energy-quantum hypothesis hold 

 for electric oscillations, that is for those oscillations whose periods are longer than 

 those of the infrared? In this case, since an energy quantum is equal to hw, 

 and v is small, the quantum would become very small. It is to be noted that the 

 sole confirmation of his hypothesis lies in his application of it to the statistical 

 theory of the elementary oscillator. His theory of radiation is a statistical 

 one derived on the assumption that the radiating body is made up of a very 

 large number of discrete elements. In order that there shall be a large number of 

 these elements they must be small, and if they are small their frequencies must be 

 high. There is, to my mind, therefore, no evidence that Planck's energy quan- 

 tum hypothesis holds for electric oscillations beyond the infra-red. 



Summary. 



1. Energy has no real existence independently of matter, and cannot exist 



free in space 



2. The types of electrical oscillators are very numerous and it is improDaD 

 that the Hertz oscillator can be considered the sole elementary type. 



3. The so-called velocity of light is not a quantity of the nature of a mechan- 

 ical velocity. Its reciprocal may, perhaps, be regarded as of the nature of a im 



reaction constant. . j 



4. Planck's energy-quantum hypothesis is a statistical hypothesis a 

 probably only true for the short waves of heat and light, and not for long elec 



waves 



5. Einstein's hypothesis of the light-quantum is untenable because it is d 

 the assumption that energy can exist free in space. 



1 hoc. cit., pp. 1249, 1250. 



