Correspondence regarding the Royal Greenwich Observatory's new transit circle, including the following items:

Correspondence with Optical Works Ltd regarding filters for use in the solar eye-piece of the transit circle, 1961.

List of optical parts and accessories for the 10-inch Cooke Refractor Telescope and transit instrument that was being offered by C. Baker of High Holborn, London, to A.N. Singh, with a request from Dr Singh regarding the R.G.O. testing the telescope before it is shipped to the Banaras Observatory, 1951.

Copy of a letter from R. Atkinson to Sir Howard Grubb, Parsons and Co. Ltd regarding microscope focus, 1948.

Correspondence with British Legation, Berne, requesting diagrams and measurements of the Airy Meridian Circle, so that a replica model could be made for the Watch and Clock Industries Exhibition in Switzerland, 1948.

Correspondence with Sir Howard Grubb, Parsons and Co. Ltd and Denfords Engineering Co. Ltd regarding instruments, 1946.

Correspondence between John Irwin of the Lick Observatory, California, and H. Spencer Jones regarding the tests of the new Greenwich reversible transit instrument, 1946.

Correspondence with Cooke, Troughton and Simms Ltd regarding trials on the pivot testing telescope of the reversible transit circle, 1946.

Correspondence with J.E. Sears of the National Physical Laboratory regarding a report on tests of the Krupp 'mikrotast' gauge, 1944.

Notes regarding the excess cost of the transit circle over the estimate, with an attached schedule showing the estimate and actual cost of component parts, 1944.

Correspondence with Sir Charles Darwin of the National Physical Laboratory regarding the new reversible transit circle of the R.G.O., 1943.

Correspondence with W. Higgins, Superintendent of the National Physical Laboratory, regarding the insulation of the piers of the transit instrument, 1943.

Correspondence with A.J. Philpot of the British Scientific Institute Research Association regarding a non-reflecting film process for treating the telescope lens, 1943.

Correspondence between H. Spencer Jones and Dr A.O. Rankine regarding the figures for each 5' division of errors of graduation of the glass circle of the reversible transit instrument, which are recurrent every 2½°, 1941.

Correspondence with Cooke, Troughton and Simms Ltd regarding the methods used for dividing the circles of the reversible transit instrument, 1941.

Correspondence with Baird and Tatlock regarding a thermometer for recording the temperature of a flat surface, 1938-1939.

Correspondence with E.R. Watts and Son Ltd, regarding a sensitive spirit level, 1938.

Correspondence with Cooke, Troughton and Simms Ltd regarding a sensitive bubble, 1938.

Correspondence with Cooke, Troughton and Simms Ltd regarding the fitting of steel collars to the pivots of the two portable transit instruments, 1937.

Correspondence with J. Jackson of the Royal Observatory, Cape of Good Hope, regarding tests on the two transit circles at the Cape, 1937.