| Description | Letters dated 1909 thanking Pearson for his lectures and guidance, and seeking advice regarding the publication of a thesis in the Proceedings of the Royal Society; letters dated 1925 in his position at Henry Hughes & Son Ltd., Manufacturers of Nautical, Aeronautical, Optical and Drawing Instruments, regarding the modification of a Rayleigh Anomaloscope to create a "Precision Anomaloscope". |