Electron capture detector for a gas chromatograph, 1960.
© Science Museum / Science & Society Picture Library
James Lovelock (b 1919), a British chemist and pioneer in the field of environmental science, developed this highly sensitive detector for measuring air pollution in 1960. In the summer of 1967 he measured the supposedly clean air blowing off the Atlantic onto the west coast of Ireland and found that it contained chlorofluorocarbons (CFCs), now know to cause ozone depletion. He elaborated his famous, but controversial, Gaia hypothesis in 1972, in which he proposed that all life on Earth interacts with the physical environment, to form a complex system which can be thought of as a single organism.