Second referee's report by Paul Adrien Maurice Dirac, on a paper 'Ultimate measurements of space and time' by H T Flint Sectional Committee: Mathematics Not recommended for publication in the 'Proceedings of the Royal Society of London'. Further study of the paper has not changed his unfavourable opinion. There is nothing definite, and hardly any mathematical deduction. The essential part is the discussion of the mathematical equations, which have little meaning. Responds to comments from the author. Understands that the referee not understanding a paper is no reason to turn it down, however in this case the author has failed to make his meaning clear. The author's previous paper in the Proceedings of the Physcial Society was much clearer than the present paper. Suggests referring the paper to Rudolf Ernst Peierls, who is more familiar with this type of quantum theory, and whose work is referred to in the text. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on verso as received 5 November 1936. [November 1936]