Henry Friedrich Wilhelm Siedentopf (22 September 1872 in

Bremen Bremen (Low German also: ''Breem'' or ''Bräm''), officially the City Municipality of Bremen (german: Stadtgemeinde Bremen, ), is the capital of the German state Free Hanseatic City of Bremen (''Freie Hansestadt Bremen''), a two-city-state consis ...

– 8 May 1940 in

Jena Jena () is a German city and the second largest city in Thuringia. Together with the nearby cities of Erfurt and Weimar, it forms the central metropolitan area of Thuringia with approximately 500,000 inhabitants, while the city itself has a popu ...

) 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 caus ...

and pioneer of

microscopy Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of micr ...

Biography

Siedentopf worked in

Carl Zeiss Carl Zeiss (; 11 September 1816 – 3 December 1888) was a German scientific instrument maker, optician and businessman. In 1846 he founded his workshop, which is still in business as Carl Zeiss AG. Zeiss gathered a group of gifted practica ...

company from 1899 to 1938. In 1907 he was nominated as the head of the microscopy department. In 1902 the

ultramicroscope An ultramicroscope is a microscope with a system that lights the object in a way that allows viewing of tiny particles via light scattering, and not light reflection or absorption. When the diameter of a particle is below or near the wavelength o ...

was developed by

Richard Adolf Zsigmondy Richard Adolf Zsigmondy ( hu, Zsigmondy Richárd Adolf; 1 April 1865 – 23 September 1929) was an Austrian-born chemist. He was known for his research in colloids, for which he was awarded the Nobel Prize in chemistry in 1925, as well as for c ...

(1865–1929) and Siedentopf, working for

Carl Zeiss AG Carl Zeiss AG (), branded as ZEISS, is a German manufacturer of optical systems and optoelectronics, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe (joined 1866) and Otto Schott (joined 1884) he laid the f ...

. The ultramicroscope was suitable for the determination of small particles and became the most important instrument of colloid research in colloid chemistry. In 1925, Zsigmondy received the

Nobel Prize for Chemistry ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "M ...

also for this work. From 1919 till 1940 he was a. o. Professor for microscopy at the

University of Jena The University of Jena, officially the Friedrich Schiller University Jena (german: Friedrich-Schiller-Universität Jena, abbreviated FSU, shortened form ''Uni Jena''), is a public research university located in Jena, Thuringia, Germany. The un ...

. He also worked on the development of micro photography and slow motion and fast motion in the cinephotomicrography. In 1908 he invented together with

August Köhler August Karl Johann Valentin Köhler (4 March 1866 – 12 March 1948) was a German professor and early staff member of Carl Zeiss AG in Jena, Germany. He is best known for his development of the microscopy technique of Köhler illumination, an imp ...

the

fluorescence microscope A fluorescence microscope is an optical microscope that uses fluorescence instead of, or in addition to, scattering, reflection, and attenuation or absorption, to study the properties of organic or inorganic substances. "Fluorescence microsc ...

. In 1930 he was elected a member of the

German National Academy of Sciences Leopoldina The German National Academy of Sciences Leopoldina (german: Deutsche Akademie der Naturforscher Leopoldina – Nationale Akademie der Wissenschaften), short Leopoldina, is the national academy of Germany, and is located in Halle (Saale). Founded ...

relates in his Nobel lecture that Siedentopf built the paraboloid condenser and the cardioid condenser.

Biography

References

Further reading