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 th ...

, 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 th ...

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 docu ...

. 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 capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter. Capillaries are composed of only the tunica intima, consisting of a thin wall of simple squamous endothelial cells. They are the smallest blood vessels in the body: ...

, 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

aerosol An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be natural or Human impact on the environment, anthropogenic. Examples of natural aerosols are fog o ...

s and

gelatin Gelatin or gelatine (from la, gelatus meaning "stiff" or "frozen") is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also ...

s, the origins of

silicosis Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust. It is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis. Silicos ...

, 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 transpar ...

in plant life and the mechanism of both

black and white Black-and-white (B&W or B/W) images combine black and white in a continuous spectrum, producing a range of shades of grey. Media The history of various visual media began with black and white, and as technology improved, altered to color. ...

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 g ...

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: ''Düsseldörp'' ; archaic nl, Dusseldorp ) is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in th ...

, he also owned a factory producing

photographic paper Photographic paper is a paper coated with a light-sensitive chemical formula, like photographic film, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a v ...

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 {{germany-chemist-stub