Letter from James Simms, Mathematical Instrument Works, 340 Woolwich Road, Charleton, to J [James] William Gifford, Oaklands, Chard Gifford's letter and photograph have reached him, and he returns the latter. The error is larger than could be ascribed to their machine and he suggests that it may be due to distortion by accident or by being attached to an untrue surface. He suggests additional observation using a second microscope to detect the extent of errors. 11 October 1906