Campman was by reputation something of a scientific recluse, difficult to dislodge from his laboratory, although he did play a full part in University and College affairs.
He married one of his research students, Muriel Holmes (a member of the university's Society of Oxford Home-Students) in 1918 and together they had a daughter, Ruth.
[3] Chapman was a science master at Giggleswick School for a time before becoming a member of staff at the University of Manchester.
Chapman had a particular interest in the photochemical reaction of hydrogen and chlorine, establishing that minute traces of impurities caused unexpected consequences.
Other areas of interest were the theory of detonation in gases (the subject of an important paper that Chapman published in 1899,[4] with reliable calculations of detonation speeds; the theory is still known as the Chapman-Jouget treatment) and the distribution of ions at a charged surface (with the name of the Gouy-Chapman layer being given to the surface layer that he envisaged).