In 1859, Gustav Robert Kirchhoff and Robert Bunsen demonstrated
the reversibility of emission lines:
"within the spectrum, an element absorbs the light at the exact location of the lines which it can emit". They stated the basic law of elementary spectrometry which states: "each element has specific properties as regards the light it emits".
They explained Fraunhofer's black lines as being caused by the
absorption of solar light by metal vapours present in the colder
layers surrounding the sun. They even identified the element responsible
for some of these black lines.
This work paved the way for atomic spectrochemistry and announced the advent of modern physics.
- 1860 - Foucault observed the absorption of spectral lines in one flame by another.
- 1864 - James Clark Maxwell presented the electromagnetic theory of light.
- 1866 - William Huggins made the first spectroscopic study of a nova.
- 1868 - A J Ångström published a compilation of all the visible lines in the solar spectrum.
- 1869 - Ångström made the first reflection grating.
- 1873 - Abbe described the optical limit in imaging.
- 1873 - Maxwell presented his 'Treatise on Electricity and Magnetism'.
- 1877 - Gouy invented the first pneumatic nebuliser for introducing liquids into flames.
- 1882 - H A Rowland greatly improved diffraction gratings, introducing curved gratings.
- 1885 - J J Balmer found a formula for the Hydrogen series; J R Rydberg and W Ritz then found formulae for other simple spectra.
- 1891 - Gabriel Lippmann made the first colour photographic plate.
- 1893 - V Schumann studied the 'vacuum' Ultraviolet.
- 1897 - J J Thomson discovered the electron.
- 1899 - Hertz developed the theory of dipole radiation, the basis of modern radio.
- 1900 - Max Planck discovered the quantum.
Authors: Jean Charles Lefebvre, Jobin-Yvon Emission, and Richard Payling, Surface Analytical
First published on the web: 15 December 1999.