284 ANNUAL, REPOET SMITHSONIAN INSTITUTION, 1931 



formula from the energy released in the process from which the 

 radiation arises. Now the.Bothe-Kolhorster experiments of about a 

 year ago seem to show that when the energies of the incident photons 

 are sufficiently high, the rays are abnormally penetrating; so that 

 it is to be expected that, for the cosmic rays produced by the forma- 

 tion of the heavier of the common elements like silicon and iron out 

 of hydrogen, the observed absorption coefficients will be somewhat 

 smaller than those computed from the energy available for their 

 formation. This is indeed the behavior which our cosmic ray 

 depth-ionization curve seems to reveal. At the highest altitudes at 

 which we have recently observed (14,000 ft.), the helium rays have 

 reached equilibrium Avith their secondaries, and the observed and 

 computed coefficients agree reasonably well. For the oxygen rays 

 the observed coefficient is a little lower than the computed value — 

 about IT per cent lower; for the silicon rays still lower — about 30 

 per cent ; and for the iron rays considerably lower still — about 60 per 

 cent; all in general qualitative agreement with the theoretical de- 

 mands as outlined. 



The foregoing results seem to point with some definiteness to the 

 following conclusions : 



1. The cosmic rays have their origin not in the stars but rather in 

 interstellar space. 



2. They seem to be due to the building up in the depths of space of 

 the commoner lieavy elements out of hydrogen, which the spectroscopy 

 of the heavens shows to be widely distributed through space. That 

 helium and the common elements of oxygen, nitrogen, carbon, and 

 even sulphur, are also found between the stars is proved by Bowen's 

 beautiful recent discovery that the " nebulium lines " arise from these 

 very elements. 



3. These atom-building processes can not take place under the con- 

 ditions of temperature and pressure existing in the sun and stars, 

 the heats of these bodies having to be maintained presumably by 

 the atom-annihilating process postulated by Jeans and Eddington 

 as taking place there. 



4. All this says nothing at all about the second law of thermo- 

 dynamics or the Wiirme-Tod, but it does contain a bare suggestion 

 that if atom formation out of hydrogen is taking place all through 

 space, as it seems to be doing, it may be that the hydrogen is some- 

 how being replenished there, too, from the only form of energy that 

 we know to be all the time leaking out from the stars to interstellar 

 space, namely, radiant energy. This has been speculatively sug- 

 gested many times before, in order to allow the Creator to be con- 

 tinually on his job. Here is, perhaps, a little bit of experimental 

 finger-pointing in that direction. But it is not at all proved or even 



