Papers concerning instruments not held by the Royal Observatory:
Correspondence with various firms regarding whether instruments are tested at the Royal Observatory, 1902.
Correspondence with the United States Naval Observatory, Washington, concerning a new altazimuth pavilion, 1903.
Correspondence with various individuals concerning the testing of clocks and watches, 1903.
Correspondence with J.E. Norris concerning a suitable clock for his observatory, 1903, including a photograph of the observatory.
Correspondence with the University of Pennsylvania regarding the reflex zenith tube, 1903.
Correspondence with various individuals regarding instruments, their testing at Kew and the addresses of makers, 1903.
Correspondence with various individuals regarding telescopes and makers, setting sundials and testing optics, 1904.
Correspondence with various individuals regarding telescopes, new designs of instruments, Brunsviga Calculating Machines and sundials, and the 'Auto Meter' car speedometer, 1905.
Correspondence concerning telescopes and eyepieces, a school orrery, sundials and student's telescopes, 1906, including a suggestion to purchase a glass prism.
Correspondence concerning telescopes and makers, old instruments, an observatory for sale in Ireland, the offer of a globe for sale, a pamphlet on the Watts Dividing Engine, and a new invention for giving latitude and time from Australia, 1907.
Correspondence with F.E. Rosse regarding his photographic reflex zenith tube for the U.S. Coast and Geodetic Survey, 1908.