1. 1883. Proc. L.M.S., republished in Rayleigh's Scientific Papers, vol. ii. art. 109.
2. See Baltimore Lectures 593 593 (letter to Professor Tait, of date 23rd Aug. 1871) and pp. 600, 601 (letter to William Froude, reprinted from ‘Nature’ of 26th Oct. 1871).