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Published online by Cambridge University Press: 14 August 2015
In a recent observation Clark et al. [1] have found that the intensity of γ-Rays of energies around 100 MeV is strong in the direction of the galactic plane; the observed intensity of the order of 10−4 cm−2 sec−1 rad−1 is greater by an order of magnitude than that predicted on the neutral pion decay hypothesis [2]. It should, however, be remarked that the theory is based on the assumption that cosmic rays are uniformly distributed in our galaxy. The assumption seems doubtful in view of the experimental result that the γ-Ray intensity depends rather strongly on the galactic longitude.