General correspondence regarding instruments, including the following items:

Correspondence with J.S. Hindle, astronomical instrument-maker, regarding the aluminising of four 20-inch mirrors, 1960.

Correspondence with C.F. Smith, scientific instrument-maker regarding his 'Projection Spectrum Comparator', 1959, including a photograph and a copy of his paper of August 1959.

Correspondence with the Admiralty regarding the Royal Hospital Transit Clock, 1957.

Memorandum by R. Atkinson on the shipping of mirrors and other important items, 1956.

Correspondence with Dr M. Ellison of the Royal Observatory, Edinburgh, regarding the Bamberg Transit Instrument, 1954.

Correspondence with Cox, Hargreaves and Thomson Ltd regarding a hollow pentagon, 1953.

Note by H. Spencer Jones on proposed alterations to the method of right ascension and zenith distance recording on the transit instruments, 1952.

Correspondence with Dr K.M. Greenland regarding a small interference filter for use in solar photography, 1951.

Correspondence with the Abinger Magnetic Station regarding various German optical components at the National Physical Laboratory, 1950.

Correspondence with P. Janssen, Brussels, regarding the gift of an astrograph sent from the Royal Greenwich Observatory, 1950.

Correspondence with Sir Howard Grubb, Parsons and Co. Ltd regarding the torque required to turn the reversible transit circle drive rod, 1950.

Correspondence with Penrose Angwin of the Festival of Britain 1951 regarding the proposed Isaac Newton Telescope, 1950.

Correspondence with Johnson, Matthey and Co. Ltd regarding evaporated coatings on front coated mirrors, 1947.

Correspondence with Sir Howard Grubb, Parsons and Co. Ltd regarding spectrograph prisms and lenses for the 36-inch telescope, 1946.

Correspondence with the Scientific Computing Service Ltd regarding the Corbett telescope, 1946.

Copy of a letter from N.B. Dunlop of East Lothian to J.G. Crowther regarding scientific instruments in his possession, 1944.

Correspondence and a report on four telescopes presented by the United States to the Home Office Executive during World War Two and the subsequent loan of three of them to the Royal Observatory, 1942.