According to recent measurements the tendency of the chemical composition above the ankle is characterized by increasing fractions of intermediate and heavy nuclei and a dominance of light nuclei around the ankle. Calculation of the chemical composition in the range 3.5 × 10 18 -5 × 10 19 eV according to new principles explains both the rising tendency of the heavy component. The calculation is prolonged to the adjacent interval 5 × 10 19 -2.4 × 10 21 eV using the same theoretical background

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... some features of the observed cosmic-ray spectrum. It results that above the energy of 6.7 × 10 20 eV, where the flux is estimated to be 1.8 × 10 −30 particles/m 2 s sr GeV, the cosmic radiation consists only of nuclei heavier than Zinc. Measurements of the spectrum of present and past experiments are compared with the calculations.