Referee's report by Robert Strutt, 4th Baron Rayleigh, on the Bakerian Lecture 'On the spectrum of hydrogen' by Thomas Ralph Merton and S Barratt Sectional Committee: Physics Recommended for publication in the 'Philosophical Transactions of the Royal Society'. Suggests adding further explanation of the method. Refers to work of Joseph John Thomson [Proceedings Vol.58, 1895], to whose work the authors' attention should be drawn. [Published in the Philosophical Transactions of the Royal Society A, 1922] Endorsed on verso as received 24 January 1922. [January 1922]