After graduating from Oxford, Lewis was a science master at
Exeter School from 1894 to 1901, Among Lewis's students at the college was
George Roger Clemo, who was greatly influenced by Lewis and went on to become a successful organic chemist. From 1925 until his retirement in 1935, he combined his position as Professor with that of Vice-Principal of the College, helping to publicise the institution throughout Devon. In his role as Professor, he was regarded as having built up the Chemistry department from nothing into a "strong and vital unit." He was responsible for the planning of the Washington Singer Building, which was opened in 1931 and was home to new chemical laboratories. Lewis was an active member of the scientific community. He was elected as fellow of the
Chemical Society in 1894, with his candidacy endorsed by his former lecturer
Henry Lloyd Snape as well as former classmate and collaborator
Frederick Daniel Chattaway. Lewis was also the local representative of the Chemical Society in Exeter from 1932 to 1936. Later in his scientific career, one of Lewis's areas of interest was
river pollution. He was credited in
Aubrey Strahan's report to the
Royal Geographical Society in 1908 for supporting the research of impurities in the
River Exe. Lewis was credited with having an instrumental role in establishing the Committee for the Furtherance of University Education in the South-West with his Exeter colleagues, Professors Walter J. Harte (1866-1954) and
Arthur Eustace Morgan (1886-1972). Lewis was made
Professor Emeritus on his retirement in 1935 == Personal life and death ==