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AKNtJAL REPORT SMITHSONIAN INSTITUTION, 1942 



All the actions and reactions in the world of physical things may be 

 expressions of three fundamental forces — gravitational, electromag- 

 netic, and nuclear. All three may ultimately be reduced to different 

 aspects of the same all-pervading, all-inclusive type. Perhaps some 



FiGTJEE 15.— Daily means of cosmic-ray intensity and geomagnetic horizontal- 

 force component, showing effect of geomagnetic storm of April 25-30, 1937, 

 on cosmic-ray intensity. 



obscure atomic effect of the extremely high pressures of the centers 

 of such bodies as the earth and the sun may be the cause of their mag- 

 netization. Therefore, experimental studies of nuclear physics 



