COSMIC RAYS MILLIKAN AND CAMERON 227 



does not exist, however, with respect to the bands corresponding to 

 p.=0.30, /A=0.0J5, and fxO.OA:. Thh wUole itjorh constitutes, then, 

 ■very powerful evidence that the sort of creative, or atom-huUding 

 'processes discussed above, are continually going on all about us, 

 probably not ait all in the stars {see below), and that each such event 

 is broadcast through the heavens in the form of the appropriate 

 cosmic ray. 



EVIDENCE THAT THE COSMIC RAYS ORIGINATE IN INTERSTELLAR 



SPACE 



If it may be regarded as established by the evidence thus far ad- 

 vanced that the cosmic rays are the signals sent out through the 

 heavens of the creation of the common elements out of positive and 

 negative electrons, the next important question to attempt to answer 

 is " where are these creative processes going on " ? To this question 

 there are just two possible answers, as follows : 



(1) In the stars where pressures, densities, and temperatures may, 

 one or all, be enormously high ; or else, 



(2) in interstellar space where pressures, densities, and tempera- 

 tures are all extraordinarily low. 



In both of these localities matter exists under extreme and as yet 

 unexplored conditions, and in view of the history of the last 30 

 years of physics, it would no longer be surprising if matter were 

 again found to behave in some hitherto unknown and unexpected 

 way as a new field of experimentation is entered. 



Of the two foregoing alternatives we think it possible to eliminate 

 the first and to establish the second with considerable definiteness, 

 and that for the tw^o following reasons : 



First. If the mere presence of matter in large quantities and at 

 high temperatures favored in any way the atom-building processes 

 which give rise to the cosmic rays, then it is obviously to be ex- 

 pected that the sun, in view of its closeness, would send to the earth 

 enormously more of them than could any other star. But the fact is 

 that all observers are agpeed that the change from midday to mid- 

 night does not influence at all the intensity of the cosmic rays. 



Since, however, the rays do come to us at all times, day and night, 

 and, according to all observers, at least, very nearly equally from all 

 directions, there is scarcely any escape from the conclusion that 

 the atom-building processes giving rise to the cosmic rays are favored 

 by the conditions existing in irderstellar space. If then, in going 

 from a point in interstellar space toward the center of a star the 

 favorable conditions for atom-building existing in outer space have 

 disappeared as the surface of the star is reached it is well-nigh 

 inconceivable that they will again reappear in penetrating from the 

 surface to the center — a path along which the changes in physical 



