Referee's report by Alfred Fowler, on a paper 'Luminescence of mercury vapour along an a-ray pencil, and transfer of nitrogen excitation to mercury' by A Luyckx Sectional Committee: Physics Recommended for publication in the 'Proceedings of the Royal Society of London'. The paper follows on from the work of Robert John Strutt, 4th Baron Rayleigh. Suggests the Communicator be asked to make improvements to the paper and correct the use of English. Suggests clarifying the references between text and plates. The importance of iron oxide requires mention in the summary. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on verso as received 16 May 1939. [May 1939]