Duboscq colorimeter, steel frame, by F. Hellige and Co., Freiburg, Germany, 1901-1914

A colorimeter compares colours of samples with standard colours during chemical analysis to determine the concentration of a sample. Samples are viewed through a monocular microscope. The Duboscq colorimeter was used in urine analysis and later blood analysis to determine concentrations of its components in physiological laboratories and medical diagnosis.

Jules Duboscq (1817-86), a French optical instrument maker, invented this type of colorimeter in 1854. It was one of the earliest colorimeters and proved to be one of the most popular.