Working notes, correspondence, annotated papers and printed pamphlets relating to telegraphy, collected by Heaviside 1872-1921. The collection comprises: Notebooks mainly consisting of mathematical equations and calculations with drafts and transcripts of papers submitted to the Philosophical Magazine and the Electrician, covering subjects such as problems with long distance signal transmission and the development of a non-distortional circuit, duplex telegraphy, the age of the earth including the development of equations for heat loss from a spherical body, measurement of resistance, eletromagnetic theory of light, the transmission of an electric charge along a wire, Maxwell's equations, vector operators for mathematical calculations; Pamphlets and publications mainly relating to telegraphy, many annotated, including works on the analysis of cathode rays, radiation, radioactivity and early attempt to define the workings of the atom, telegraphy and telephony; Papers, comprising rough notes and calculations, including drafts of papers such as Operators in Physical Mathematics Parts 2 and 3, proof copies of Electromagnetic Theory with notes and calculations on the reverse, and correspondence with The Electrician and other periodicals over the publication of his articles; Official awards and honours presented to Heaviside and other assorted items, including the award of Cedergren Medal and Gottingen University Honorary Doctorate, 1924; Notes by Heaviside on plane waves and electrification, the application of zonal harmonics on physical problems, magnetic induction, gravitational dimensions, the magnetism of the earth, on the backs of old letters; Correspondence from notable scientists and mathematicians including Sir Oliver Lodge, W E Ayrton, W H Bragg, S P Thompson, and Sir William Thomson, Baron Kelvin of Largs; Material found at Paignton, 1957, including Preliminary drafts of articles for Electromagnetic Theory; annotated galley proofs of Electromagnetic Theory; assorted papers, spare proofs of papers and miscellaneous correspondence, and additional correspondence sent to Heaviside.