Miscellaneous correspondence regarding matters relating to magnetic instruments, including the following material:

Correspondence with Adam Hilger Ltd regarding a quartz-fibre vertical force magnetograph, 1920-1924.

Miscellaneous correspondence relating to the repair, purchase and testing of magnetic instruments, 1923-1937, including the repair of Elliot Magnetometer No. 75 by Elliott Bros., the testing of the Shuster-Smith Magnetometer for Abinger, the return to the Royal Observatory of Magnetometer No. 161, and the ordering of a galvanometer from the Cambridge Instrument Co.

Correspondence with the Cambridge Instrument Co. regarding a new magnetograph and reordering mechanism for the new Magnetic Pavilion, 1912-1916.

Correspondence with the Admiralty regarding equipment for a new Magnetic House, contracts, estimates and costs, 1913-1914.

Correspondence with the Cambridge Instrument Co concerning the supply of quartz-fibres for the suspension of a declination magnet, 1913.

Correspondence regarding tungston-wire suspension for magnetometers, 1914.

Correspondence regarding the deflection bar of a high frequency magnetometer sent for testing to the National Physical Laboratory, 1914.

Correspondence on the loan of a Watson Quartz Fibre V.F. Magnetograph from Eskdalemuir and its repair at the Imperial College of Science and Technology, London, 1915-1916.

Correspondence with Adam Hilger Ltd regarding a convex lens and plane quartz mirror loaned from Eskdalemuir, 1915-1916.

Correspondence with John Grundy regarding a drawing of apparatus for keeping the temperature constant in the new Magnetic Pavilion, 1916.