Referee's report by William Cawthorne Unwin, on a paper 'A throw-testing machine for reversals of mean stress' by Osborne Reynolds and J H Smith Sectional Committee: Physics and Chemistry Recommended for publication in Philosophical Transactions, in full. The heading to the last column of table six appears erroneous. All the illustrations are required but a scale drawing of the machine would be much more useful than the photograph. [Published in Philosophical Transactions A, 1902]. Endorsed on verso as received 21 April 1902. 20 April 1902