 Knibbs was also taking an active interest in other societies, and was president of the Institution of Surveyors at Sydney for four years in the period between 1892 and 1901, and president of the New South Wales branch and a member of the British Astronomical Association in 1897-8.Knibbs had begun contributing papers to the Royal Society of New South Wales at an early age, at first on matters arising out of surveying, and then on problems of physics.In his presidential address delivered on 3 May 1899 Knibbs showed that he had spent time studying mathematics.