224 



ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1928 



of the bend in the ionization-depth curve is completely incompatible 

 with any general distribution of the frequencies of cosmic rays 

 like that found in white light, or in the general X radiation which 

 is produced by the bombardment of the atoms of a target by high- 

 speed electrons (cathode rays). 



Third. — If the Einstein special theory of relativity may be taken 

 as a sound basis of reasoning — and no results predicted by it have 

 ever thus far been shown to be incorrect, while it has many striking 

 successes to its credit — then it follows that radiant energy can never 

 escape from an atomic system without the disappearance of an equiva- - 

 lent amount of mass from that system, these relations being con- I 

 tained in the now well-known and universally used equation of 



24 



55 



i8 



40 50 60 70 



Figure 1.- — Ionization in ce./sec. against depth in equivalent meters of water beneath 

 top of atmosphere ; upper curve 8 to 40 meters, lower 38 to 70 meters 



Einstein (1905) Mc - ^ E, where M is mass in grams, c is the velocity 

 of light in centimeters per second and E is energy in ergs. Now 

 through the recent, very exact work of Aston -- we know the mass 

 of every one of the atoms with a great deal of certainty, and we can 

 therefore compute the amount of ether-wave energy that can be gen- 

 erated by any sort of atomic transformation that can take place, and 

 knowing this energy we can compute with the aid of the Einstein 

 equation the frequency, and with the aid of the Dirac formula ^^ the 

 penetrating powers of the rays resulting from all possible atomic 

 transformations. Such studies reveal the fact that there are no pos- 

 sible transformations cafohle of yielding rays of the enormous pene- 

 trating power observed by MiUikan and Cameron except those cor- 



" Aston, Proc. Roy. Soe., 115, 487 (1927). 

 == Dirac, ibid., 109, 206 (1925). 



