Dobson ozone spectrophotometer

The Dobson spectrophotometer, also known as Dobsonmeter, Dobson spectrometer, or just Dobson is the earliest instrument used to measure atmospheric ozone. It was invented in 1924 by Gordon Dobson. A history of the development of the instrument is here and an example of one of Dobson's own instruments remains on display in the University of Oxford Department of Physics.