COSMIC-RAYS OF THE HIGHEST ENERGIES .2. THE MASS COMPOSITION AND PRIMARY SPECTRUM

In the previous paper we presented evidence for an enhancement of cosmic ray flux above 10(19) eV from the galactiv plane in the outer galaxy and for the likely existence of discrete sources both within the plane and away from it. Here we study the mass composition and energy spectrum of both the 'source' particles and the general flux. It is concluded that there is quite strong evidence for an increase in the fraction of heavy nuclei as one proceeds above 10(19) eV, particularly from the intermediate latitudes, these particles being of galactic origin, but at the very highest energies, E greater-than-or-equal-to 3 x 10(19) eV, protons may well dominate again; such protons would be of extragalactic origin.