Referee's report by Arthur Mannering Tyndall, on a paper 'The ionization of helium by neutral helium atoms' by Frank Horton and Dorothy M Millest Sectional committee: Physics Recommended for publication in Proceedings. It is a 'substantial contribution' to a subject that has received attention elsewhere. The paper should be shortened in two places, as there are too many detail. The paper 'smacks of a doctor's thesis where one would expect it'. No reference has been made to metastable atoms. [Published in Proceedings of the Royal Society A, 1946]. Date received not given. 19 March 1945