Second 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 Communicator has made many amendments to the paper, which is now ready for the printers. Suggests the editor of the Proceedings read the paper carefully, and make any necessary alterations to the numbering of the figures. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on verso as received 26 June 1939. [June 1939]