Referee's report by James Alfred Ewing, on the Bakerian Lecture 'The constitution of the Copper-Tin series of alloys' by Charles Thomas Heycock and Francis Henry Neville Sectional Committee: Physics and Chemistry Recommended for publication in Philosophical Transactions. In general the paper is a remarkably clear and thorough discussion of an exceedingly complex subject. To abbreviate it in any way, or to reduce the number of illustrations, would be to injure it. [Published in the Philosophical Transactions A, 1904]. Endorsed on verso as received 20 April 1903. April 1903