Letter from Alexander Muirhead, FRS, The Lodge, Shortlands, to James Mackenzie Davidson Apologises for having failed to return the tube of radium before now. Notes that he would like to borrow it again when Mackenzie Davidson returns as a standard for the calibration of the Wilson electrometer he has. Asks if Mackenzie Davidson has J. [Joseph] J. [John] Thomson's book 'Conduction of Electricity through gases' and [Ernest] Rutherford's on Radioactivity. Notes that Rutherford's is more useful than [Frederick] Soddy's. Suggests that when Mackenzie Davidson return they do some work together on radioactivity. 27 July 1904