Heinrich Gustav Johannes Kayser

ForMemRS Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural knowledge, including mathematic ...

(; 16 March 1853 – 14 October 1940) was a German

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

and spectroscopist.

Biography

Kayser was born at

Bingen am Rhein Bingen am Rhein () is a town in the Mainz-Bingen district in Rhineland-Palatinate, Germany. The settlement's original name was Bingium, a Celtic word that may have meant "hole in the rock", a description of the shoal behind the ''Mäuseturm'', k ...

. Kayser's early work was concerned with the characteristics of acoustic waves. He discovered the occurrence of

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic ta ...

in the

Earth's atmosphere The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...

in 1868 during a

solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of the Earth, totally or partially. Such an alignment occurs during an eclipse season, approximately every six mon ...

when he detected a new

spectral line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to ident ...

in the solar spectrum. In 1881 Kayser coined the word “

adsorption Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a ...

”. Together with Carl Runge, he examined the spectra of

chemical element A chemical element is a species of atoms that have a given number of protons in their atomic nucleus, nuclei, including the pure Chemical substance, substance consisting only of that species. Unlike chemical compounds, chemical elements canno ...

s. In 1905, he wrote a paper on

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have n ...

theory.Kayser, Heinrich. (1905). Die elektronentheorie. DC Heath & Company. The kayser unit, associated with

wavenumber In the physical sciences, the wavenumber (also wave number or repetency) is the '' spatial frequency'' of a wave, measured in cycles per unit distance (ordinary wavenumber) or radians per unit distance (angular wavenumber). It is analogous to te ...

, of the CGS system was named after him. He died at

Bonn The federal city of Bonn ( lat, Bonna) is a city on the banks of the Rhine in the German state of North Rhine-Westphalia, with a population of over 300,000. About south-southeast of Cologne, Bonn is in the southernmost part of the Rhine-Ru ...

in 1940.

Delegates to the Fourth Conference International Union for Cooperation in Solar Research at Mount Wilson Observatory

Works

* ''Lehrbuch der Physik für Studierende'' . Enke, Stuttgart 3rd ed. 190
Digital edition
by the

University and State Library Düsseldorf The University and State Library Düsseldorf (german: Universitäts- und Landesbibliothek Düsseldorf, abbreviated ULB Düsseldorf) is a central service institution of Heinrich Heine University. Along with Bonn and Münster, it is also one of t ...

References

External links

* 1853 births 1940 deaths Foreign Members of the Royal Society 20th-century German physicists People from Mainz-Bingen University of Bonn faculty People from Rhenish Hesse 19th-century German physicists {{Germany-physicist-stub