George N. Blackshaw, agricultural chemist, held a Bachelor of Science (BSc) degree and was a Fellow of the (British) Chemical Society. Around the beginning of 1904 he was appointed resident lecturer in chemistry at the Government School of Agriculture at Elsenburg, near Stellenbosch. During the next few years he lectured also in botany. In June 1909 he was transferred to the newly established analytical laboratory of the Department of Agriculture of Southern Rhodesia (now Zimbabwe), in Salisbury (now Harare), as agricultural chemist (later chief chemist). The Department of Agriculture was headed by Dr E.A. Nobbs* and the other staff included R.W. Jack* (entomologist) and H.G. Mundy* (agriculturalist and botanist).
Blackshaw remained in his post until 1926. His work consisted mainly of the analysis of soils, manures, milk, and other agricultural products. He also investigated the proposed production of sugar, alcohol and paper from maize plants. Although the initial results were not encouraging, he published an account of the work in "The sugar content of maize stalks" (Report of the South African Association for the Advancement of Science, 1911, pp. 269-273; and 1912, pp. 42-48). His other scientific publications included the following: "Lime deposits of Rhodesia and their value" (Rhodesia Agricultural Journal, 1911, Vol. 9(3), p. 313); and "Magnesia impregnated soils" (South African Journal of Science, 1920, Vol. 17, pp. 171-179).
Blackshaw was elected on the council of the Cape Chemical Society in April 1909, but was not re-elected the next year after he had moved to Salisbury. He joined the South African Association for the Advancement of Science in 1905. At the association's annual congress held in Bulawayo in 1911 he was joint secretary of Section B (which included chemistry). He served on the association's council for at least the year 1912/3. After his move to Zimbabwe he joined the Rhodesia Scientific Association, serving as its president for 1924/5. By 1920 he had been honoured as an Officer of the Order of the British Empire (OBE).