Raphael Eduard Liesegang () (1 November 1869 – 13 November 1947) was a German
chemist
A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe t ...
, photographer and
entrepreneur
Entrepreneurship is the creation or extraction of economic value. With this definition, entrepreneurship is viewed as change, generally entailing risk beyond what is normally encountered in starting a business, which may include other values t ...
born in
Elberfeld
Elberfeld is a municipal subdivision of the German city of Wuppertal; it was an independent town until 1929.
History
The first official mentioning of the geographic area on the banks of today's Wupper River as "''elverfelde''" was in a doc ...
.
He is known for his work on
Liesegang rings
Liesegang rings () are a phenomenon seen in many, if not most, chemical systems undergoing a precipitation reaction under certain conditions of concentration and in the absence of convection. Rings are formed when weakly soluble salts are produc ...
. He also helped develop the methods of
capillary analysis, a precursor to
paper chromatography
Paper chromatography is an analytical method used to separate coloured chemicals or substances. It is now primarily used as a teaching tool, having been replaced in the laboratory by other chromatography methods such as thin-layer chromatography ...
, published a paper on the possibility of
television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
(years before the discovery of the electron), contributed to
chromosome theory
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
, worked on properties of
aerosols and
gelatins, the origins of
silicosis, the role of
carbon dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...
in plant life and the mechanism of both
black and white and
colour photographic processes.
The son of a painter (and eventual photographer), Liesegang longed for an artistic career but lacked the ability to draw or paint. His father would later invent a camera and photography would go on to be one of Liesegangs passions. Research into
photographic emulsion
Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of glas ...
s led to his personal discovery of Liesegang rings. He was not the first person to observe the effect, but they bear his name, as he devoted so much time to researching them.
As an heir to the founder of
Ed. Liesegang oHG,
Düsseldorf
Düsseldorf ( , , ; often in English sources; Low Franconian and Ripuarian language, Ripuarian: ''Düsseldörp'' ; archaic nl, Dusseldorp ) is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second- ...
, he also owned a factory producing
photographic paper and chemicals. Ed. Liesegang oHG later expanded into optics manufacturing, and sold its photochemical interests.
He has published the first German brochure on television
''Beiträge zu Problem des elektrischen Fernsehen'' 1st edition 1891,
2nd edition 1899
References
*
* Heinz K. Henisch, Crystals in gels and Liesegang rings
Le grand chimiste allemand Raphael Eduard Liesegang contribue à la question de la télévision électrique, "problème du présent" (1889–1899)
19th-century German chemists
1869 births
1947 deaths
20th-century German chemists
People from Elberfeld
Scientists from Wuppertal
Businesspeople from Wuppertal
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