Referee's report by Herbert McLeod, on a paper 'A new manometer, and on the law of pressure of gases between 1.5 and 0.01 millimetres of mercury' by John William Strutt, Lord Rayleigh Sectional Committee: Physics and Chemistry Recommended for publication in Philosophical Transactions, in full with no modifications. All the illustrations are necessary. The paper exhibits the author's characteristic ingenuity and extreme care in all the minutest details. The results of the delicate measurements are extremely concordant and fully prove the truth of Boyle's law at low temperatures. [Published in Philosophical Transactions A, 1901]. Endorsed on verso as received 21 February 1901. February 1901