Daniel John May, surveyor and Staff-Commander in the Royal Navy, reported to the government of the Cape Colony on his survey of the mouth of the Mtata River in 1882. In 1889 he succeeded W.E. Fry* as secretary of the Meteorological Commission of the Cape of Good Hope. He held this position until late in 1893. During his term of office he visited almost all the meteorological observers in the colony who regularly provided data to the commission, to inspect their instruments, compare them with his portable standards, and assess their locations. Such inspections were essential, but not always sufficient, to ensure reliable data. During 1893 May undertook three tours of inspection. The first covered Cape Town and the Cape Peninsula and the resulting report was written on 10 March. The second tour, from 29 May to 5 July, covered the western and north-western regions of the colony up to Port Nolloth, from where he returned to Cape Town by ship. The third tour took him to the Karoo and as far north as Kimberley, and was described in a report dated 2 October. He was succeeded as secretary by C. Roland Pillans*. Copies of his journals and a biography by his son are in the National Library of South Africa, Cape Town.