Rawson W. Rawson, colonial civil servant, was the eldest son of Jane Rawson and Sir William Adams, who adopted his wife's surname when they married. Rawson began his career as a clerk in the Board of Trade in 1829 and from 1834 to 1842 served as secretary to two successive presidents of the Board. Meanwhile he had developed an interest in statistics and in 1829 read a paper on "An inquiry into the statistics of crime in Englamd and Wales" before the statistical section of the British Association for the Advancement of Science. From 1838 to 1842 he served as honorary secretary of the Statistical Society of London and editor of its journal. In the latter year he was transferred to Canada as chief secretary and when that post was abolished in 1844 went to Mauritius as treasurer and paymaster-general. He married Mary-Anne Ward in 1849 and they had at least four children. Their second son was Colonel Herbert E. Rawson*.
In May 1854 Rawson was appointed colonial secretary at the Cape of Good Hope, arriving in May that year. His post made him the chief executive in the Cape government and a member of the Executive Council. Attending debates in both Houses of the first Cape Parliament he did much to instruct their members in parliamentary procedure. The successful functioning of the first parliament (1854-1858), and the cordial relations between parliament and the government, were largely ascribed to Rawson's expertise and patience. In addition his administrative duties included the supervision of all the work normally associated with government departments of public works, finance, justice, education, native affairs, welfare, etc. In recognition for his services he was created a Commander of the Order of the Bath (CB) in 1858.
Rawson was a man of great ability and had a capacity for hard work. His many interests included some scientific subjects. He chaired a government committee to investigate the possibility of forming a museum in Cape Town and in May 1855 reported that a museum should be established, a building for it provided, and a parliamentary grant be made available to finance it. The South African Museum was established by the Governor, Sir George Grey, who appointed Rawson and Dr C.W.L. Pappe* as trustees. Rawson served as trustee until 1860, when he temporarily left the Cape. He was again appointed in 1862, serving until he left the Cape for good in 1864. In 1855 he donated most of the museum's shell collection.
Rawson collaborated with Pappe in a study of South African ferns and they published an extensive two-part paper, "Synopsis filicum Africae Australis; or, an enumeration of the South African ferns" in the Cape Monthly Magazine (November and December 1857, Vol. 2, pp. 257-287, 359-381). The paper contained descriptions of 160 species and a classification of the genera. It was re-published as a monograph entitled Synopsis filicum Africae Australis; or, an enumeration of the South African ferns hitherto known (Cape Town, 1858, 57p). On 1 August that same year, having submitted a proposal to Rawson for the creation of the post of government botanist, Pappe was appointed to this position. When Pappe died in 1862 Rawson ensured that the government purchased his personal herbarium. He sent specimens of ferns to the Royal Botanic Gardens at Kew, near London, and corresponded with its director, Sir William Hooker on matters relating to ferns. The plant genus Rawsonia was named after him by W.H. Harvey* and O.W. Sonder*, and in the preface to Volume 3 of the Flora Capensis (1865) they thanked him for the interest he took in the project and for his powerfull advocacy in the Cape Parliament (to obtain financial support). A few years earlier Harvey had already dedicated the first volume of his Thesaurus Capensis(1859) to him.
When the Cape of Good Hope Horticultural and Floricultural Society was founded in Cape Town in 1856 Rawson was elected chairman of its first committee. He also served on the committee of the Cape of Good Hope Agricultural Society.
He left the Cape in July 1864 to take up an appointment as governor of the Bahama Islands. The next year he became lieutenant-governor of Jamaica and in 1869 governor-in-chief of the Windward Islands. He retired to London in 1875 and that same year was honoured as a Knight Commander of the Order of St Michael and St George (KCMG). After his retirement he maintained his interest in statistics and from 1885 to 1896 was president of the International Statistical Institute. He became president of the Royal Statistical Society in 1884 and was a member of both the Statistical Society of Paris and the Central Statistical Commission of Belgium. Furthermore he was vice-president of the Royal Geographical Society until just before his death, and a member of, among others, the American Philosophical Society. His many published reports included the following: Statistical description of the Bahamas, and account of the hurricane of 1866 in those islands (1866), Report on the rainfall of Barbados and upon its influence on the sugar crops 1847-71, with two supplements, 1873-1874 (1874), International vital statistics (1885, and Analysis of the maritime trade of the United Kingdom, 1869-1889 (1890). His contributions to the measurement of rainfall included a paper on "Periodicity of rainfall" in Nature (1874), and were acknowledged by the American meteorologist Professor Cleveland Abbe*, who wrote (Todd & Abbe, 1890, p. 565): "At Barbados I... was delighted to find that the magnificent system of rainfall stations developed by Sir Rawson W. Rawson, Governor at Barbados 1866-1875, is still maintained by the government; and although the number of stations had fallen from 250 to 80, yet the system remains one of the best in the world".
Rawson's herbarium of some 2000 ferns, collected in Mauritius, the Cape of Good Hope and the West Indies, was purchased by the British Museum (Natural History) in 1900. Specimens from him are also in the herbarium of Kew Gardens and in the Compton Herbarium, National Botanical Institute, Cape Town. The small town Rawsonville in the Western Cape was named after him.