Referee's report by Nevill Francis Mott, on a paper 'Coriolis perturbations in the methane spectrum. IV. Four general types of Coriolis perturbation' by H A Jahn Sectional Committee: Physics Recommended for publication in the 'Proceedings of the Royal Society of London'. The paper seems correct as regards the theoretical physics. The results should be looked at by someone familiar with band spectroscopy, especially as further papers are being prepared. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on verso as received 6 March 1939. [March 1939]