Letter from J. H. Gardiner, 59 Wroughton Road, Balham, to James Mackenzie Davidson Alerts Mackenzie Davidson to his desire to carry out an experiment to test if one can detect any difference in the x-rays produced at the focus of the cathode stream from those paracathodic rays produced in a working tube. Notes that there is no doubt that the latter differ from proper cathode rays. If this difference is proven, asks if Mackenzie Davidson will approach A. [Alan] A. [Archibald Campbell] Swinton in order that he can try the experiment with Swinton's battery and make absolutely certain that there is no electricty at the anticathode. Also notes that he does not like Mackenzie Davidson's Mural rays; the rays that produce them cannot be cathode rays in the ordinary way. Makes some suggestions as to Mackenzie Davidson's description of his pin-hole experiment. 27 January 1912