Referee's report by Sydney Chapman, on a paper 'Time-lag in a control system' by A Callender, Douglas Rayner Hartree and A Porter Sectional committee: Mathematics Not recommended for publication. The paper is 'able', but is not of sufficient scientific importance to be published by The Royal Society. It would be better off published in a technical journal, specifically one devoted to scientific instruments. An abstract may be worth publication by the Society. [Published in Philosophical Transactions A, 1936]. Endorsed on verso as received 15 October 1935. October 1935