Referee's report by Alfred Fowler, on a paper 'The spark spectrum of thallium, Tl III' by John Cunningham McLennan, A B McLay and M F Crawford Sectional Committee: Physics Recommended for publication in the 'Proceedings of the Royal Society of London'. [Published in the 'Proceedings of the Royal Society of London' A, 1929] Endorsed on verso as received 11 June 1929. 10 June 1929