Clifford Hiley Mortimer. 27 February 1911 — 11 May 2010

The passing of Clifford Hiley Mortimer, shortly before the centenary of his birth, ended a scientific career that was as varied and versatile as it was long. Few investigators of a natural environment—here that of lakes—penetrated so deeply and widely over the range of physics, chemistry and biology. In this setting he won worldwide respect; he was ‘at home’ with personal relations, language and professional enterprise in Britain, central Europe and North America. In science he had an ability to combine ‘hands on’ practicality with deep theoretical penetration. He could combine his science with historical essay, elegant draughtsmanship, the inspiration of students and the administration of a research institute. All these appeared in the first half of his life. He worked methodically and with tenacity of purpose, even in the vicissitudes of extreme age. In his nineties he published a major book centred on the physics of Lake Michigan, beside which lake he then lived. The near-final draft of another work, intended to inform students on water density within inland waters, was in existence on his death in his hundredth year.