Scope and Contents Correspondence and related papers on the time signal and time ball service, including the failures of the Greenwich time signal; requests for information on time balls; the establishment of time balls or guns at Queenstown, Sheffield, Bristol and Manchester; a paper by S.P. Langley 'On the Allegheny system of electrical time signals'; experiments with the Post Office chronopher; corrections and errors of the Post Office and Westminster clocks; the system of operation employed by the London...