List of sources:
Cape of Good Hope. Civil service list, 1896, 1899, 1903.
Cape of Good Hope. Report of the Meteorological Commission, 1879, 1880, 1897, 1901-1904.
FamilySearch: Charles Collis Hammond. https://ancestors.familysearch.org/en/G3LH-N2Q/charles-collis-hammond-1859-1935 AND https://www.familysearch.org/ark:/61903/3:1:33SQ-G5FL-VF4?view=index&personArk=/ark:/61903/1:1:7MRC-PNZM&action=view&cc=1779109
General directory and guide book to the Cape of Good Hope and its dependencies... (title varies), 1868, p. 230; 1869, p. 361.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to Hammond, Charles Collis/Hammond, C.C.
Venter, R.J. Bibliography of regional meteorological literature. Vol. 1. Southern Africa, 1486-1948. Pretoria: Weather Bureau, 1949.