(1) General correspondence regarding time balls, 1879-1893, including the following material:

Correspondence regarding reprints, ordered by G.B. Airy in 1880, of articles from 'Nature', 1876, concerning the distribution of time signals.

Correspondence, 1879-1880, regarding the Prussian Government's request for information on colonial time in South Africa, Canada, India, St Helena, Mauritius, Australia, Tasmania and New Zealand, and similar requests from the U.S. Hydrographic Office.

Advice given to the Transvaal Government with regard to a time ball for Pretoria, 1879.

Information given to the Hydrographer regarding the Royal Observatory and the Deal Time Ball, 1880.

Correspondence regarding the enquiry of M.L. Manchez concerning time signals, 1880.

Correspondence with the Harbour Department regarding the transmission of time signals to different parts of the United Kingdom, 1880.

Correspondence relating to Maxwell Hall's proposed system of time signals and storm warnings for the West Indies, 1878-1879.

Correspondence regarding the Hong Kong Time Ball, 1883.

Correspondence regarding the Amsterdam Time Ball, 1881.

Correspondence regarding a revised list of time signals of the Hydrographic Department, 1885.

Correspondence regarding the establishment and maintenance of British time balls, 1884-1888, including correspondence with Lloyd's relating to the setting up of time balls, providing the difference in time between Greenwich and various other places and the mean time of high tide at London Bridge and at various other ports, 1885.

Correspondence regarding information supplied to Plymouth Borough engineers on time ball apparatus, 1885.

Correspondence, newscuttings and a Harbour Board notice and report relating to the Southampton Time Ball, 1885.

Miscellaneous enquiries regarding time balls, 1881-1892, including prices and estimates of the cost of apparatus, suppliers, etc.; advice on apparatus; and particulars of the Greenwich Time Ball.

Correspondence regarding the Brisbane Time Ball, 1891, including its erection and cost, and correspondence with Saxby and Palmer concerning its manufacture.

Correspondence with Crown agents and manufacturers regarding the time ball for the Grenada Government, 1892-1893, including specifications and estimates.

(2) Correspondence regarding the time ball for the Straits Settlements (Singapore) on Mount Serapong, 1888-1892.

The correspondents are Crown agents and firms involved with the time ball. There is correspondence with E. Dent and Co., regarding clocks; Troughton and Simms, regarding a portable transit circle; Messrs Fuller and Son, regarding the electric trigger apparatus; J. Mercer, regarding chronometers; V. Kullberg, regarding clocks; and Captain C. Crawford, regarding the testing of the transit circle. There are also plans and blueprints of the apparatus.

(3) Correspondence with Lloyd's regarding the setting up of time balls at their signal stations at home and abroad, 1896.

(4) Correspondence regarding proposed time balls, 1897-1905, comprised of advice on manufacturers and suppliers, equipment and apparatus, estimates and other matters, including the following material:

Correspondence with Crown agents regarding the time ball for Mauritius, 1897.

Correspondence with Lloyd's, 1899, regarding the setting up of time balls at their signal stations at Tangier, Gibraltar and Malta and the transmission of the Greenwich Time Signal.

Correspondence with the Oriental Telephone Company regarding electrical apparatus, 1904.

Correspondence with M. Trépied regarding the time ball for Algiers.

(5) Correspondence with the Master Attendant, Crown agents and E. Dent and Co. regarding the time ball and town clock for Colombo, Ceylon, 1912-1915, including details, specifications, reports of inspections, complaints, etc.

(6) General correspondence regarding time balls, 1912-1927, including the question of what causes a time ball to drop and the irregularity of the Norwich Time Ball.