Letter from Thomas Gold to Academician Sergey Mandelshtam, PN Lebedeva Institute of Physics -- FIAN, Moscos [Moscow], USSR Thanks him for his letter and preprint. Says that he understands and agrees with Mandelshtam's points. Says that 'I am not quite clear, however, whether one would have to assume that kilovolt electrons would necessarily be either present diffusely in the vicinity of the Moon, or be absent'. Goes on to talk about it in more detail. 1 February 1968