Gerald Creagh Scully, chemist, was the son of the plant collector William Charles Scully* and his wife Honoria Emily, born Richards. He attended the Boys' High School, Stellenbosch, and passed the matriculation examination of the University of the Cape of Good Hope in 1907. Continuing his studies at Victoria College, Stellenbosch (forerunner of the University of Stellenbosch) he was awarded the BA degree with honours in chemistry by the University of the Cape of Good Hope in 1911. He stayed on at the college for the next two years and was awarded the MA degree in chemistry in 1913. Meanwhile he had been assisting Professor Robert Broom* (in 1912) and Professor Ernest J. Goddard* (in 1913) with geology and mineralogy, and in 1912 presented a number of mollusc shells from the raised beaches of Algoa Bay to the South African Museum in Cape Town.
After graduating Scully taught chemistry at the Huguenot College, Wellington, until June 1915. At this time he and A.R.E. Walker* published a 'Note on spodumene from Namaqualand' in the Transactions of the Royal Society of South Africa (1914/5, Vol. 4, pp. 65-68). He was next employed at the Dynamite Factory, Somerset West, where he remained to at least 1936.
Scully was awarded an honorary Doctor of Science (DSc) degree by the University of Natal. He was a Fellow of the Royal Institute of Chemistry (FRIC) and by 1917 was a member of the Royal Society of South Africa. He became a member of the South African Chemical Institute in 1937 and was still a member in 1958. In 1959 he was re-appointed as a member of the Council for Scientific and Industrial Research.
In December 1915 Scully married Muriel Powell, with whom he had a son and two daughters.