Referee's report by William Cawthorne Unwin, on a paper 'On the conditions for effective scour in drain-pipes of circular section' by Henry Hennessy Not recommended for publication in the Proceedings of the Royal Society of London. The paper gives no practical results. It is 'the worst type of merely mathematical solutions of practical problems'. Subject: Physics, Applied Sciences, Mathematics [Published in the 'Proceedings of the Royal Society of London', 1889] 9 March 1889