Referee's report by Alfred Fowler, on a paper 'Hyperfine structure in the arc spectrum of bromine' by Samuel Tolansky and S A Trivedi Sectional Committee: Physics Recommended for publication in the 'Proceedings of the Royal Society of London'. The paper provides a great advance in accuracy for such observations, and the theoretical interpretations are based on good internal evidence. Suggests some of the tables could be retained in the archives, rather than printing in full, however as the tables are not very extensive, and the progress made substantial, they may be printed in full this time. Suggests the authors prepare another version of the paper, in case the tables are not printed in full. Makes some suggestions regarding the diagrams. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on verso as received 13 December 1939. [December 1939]