Letter from K. Schall, K. Schall & Son, Electrical Engineers, 75 New Cavendish Street, London, to James Mackenzie Davidson Informs Mackenzie Davidson that he recently received a letter from the Kny Scheerer Co. saying they cannot do anything with the patent unless they have the original and a properly signed assignment, two copies of which are enclosed [not enclosed]. With regards to Mackenzie Davidson's interrupter, notes that two models are finished and producing an excellent output, while the third should be ready in four weeks. 17 February 1911