Set of standard solutions used in spectroscopy, 1870-1871.

A set of sealed glas vials containing aqueous solutions that were used for comparision to materials being examined using the spectroscope. Produced by John Browning, London, around 1871, these solutions would produce spectra at known wavelengths. Used in conjunction with specimens being analysed, they would give a comparison spectra in the spectroscope from which the wavelength of the unknown substance could be found and its identity uncovered.