Referee's report by Ralph Howard Fowler, on a paper 'Relaxation methods applied to engineering problems VIIC - Free transverse vibrations of membranes, with an application (by analogy) to two-dimensional oscillations in an electro-magnetic system' by D N De G Allen, L Fox, H Motz and Richard Vynne Southwell Sectional Committee: Engineering Recommended for publication in the 'Philosophical Transactions of the Royal Society'. Contains extra question - 'Is there any information contained in the paper which likely to be of value to the enemy?' Referee replies yes, secret printing required. [Published in the Philosophical Transactions of the Royal Society] Endorsed on verso as received 14 March 1941. [1941]