Robert Bunsen

Robert Whilhelm Eberhard Bunsen was born on March 31, 1811 in Gottengen, Germany. His father, Christian Bunsen was the chief librarian and a professor at the University of Gottengen where Bunsen studied chemistry earning a PhD in 1831 at the age of nineteen. After finishing his doctorate Bunsen spent three years traveling through Europe, partially at the expense of the German government during which he studied a multitude of subjects. When he returned to Gottengen he served as a lecturer in chemistry. Beginning in 1836 he taught chemistry at the Polytechnic School of Cassel, and in 1839 he was appointed professor of chemistry at the University of Marburg where he remained until 1851. After a brief stint at the University of Breslau, in 1852 he became chair of chemistry at the University of Heidelberg, where he remained until retirement in 1889.

Bunsen's early research involved compounds of arsenic. He developed the use of iron oxide hydrate to precipitate arsenate which is still used to treat arsenate poisoning. He continued his studies of arsenic at the cost of almost poisoning himself and with the loss of an eye, injured by exploding glassware. One of his most lasting contribution to science was the invention of his eponymous burner. At the time chemists used oil and alcohol lamps as a source of flame. In 1854 Bunsen had gas piped into his laboratory and when none of burners available met his needs he developed his own, that produced a colorless flame, the intensity of which could be adjusted.

Using his new burner Bunsen tested different chemicals and observed different colors and was able to detect different elements based on the colors produced. Sometimes color produced by one element would mask another and he used colored glass to mask some elements. Not satisfied with this solution, he mentioned his problem to Gustav Kirchoff, a Russian physicist and using two parts from telescopes, a prism, and a cigar box with its inside covered in black the pair made a prototype spectroscope. Using their new spectroscope Bunsen and Kirchoff quickly were able to identify different elements by their spectra. In order to find undiscovered elements Bunsen had 40 tons of mineral water evaporated and he was able to identify for the first time the alkali metal elements cesium (from the Latin ceasium, sky blue, named for its blue spectral lines) and rubidium (from the Latin rubidius, or dark red, named for its red spectral lines). Today spectroscopes are widely used in chemical analysis.

Bunsen died on August 16, 1889 in Heidelberg.


References:

Fujinaka, Pam and Kerekes, Christina; "Robert Wilhelm Bunsen (1811-1899)"; retrieved from woodrow.org

Morris, Richard; Last Sorcerers: Path from Alchemy to the Periodic Table; Joseph Henry Press; 2003

Robert Whilhelm Bunsen NNDB profile

Robert Bunsen Wikipedia Entry

Sidney W. Fox

Sidney Walter Fox was born on March 24, 1912 in Los Angeles, California. His father, Jacob Fox, was a wigmaker and his mother, Louise Berman, was a Ukrainian immigrant. He attended the University of California Los Angeles, earning a bachelors in chemistry and the California Institute of Technology, earning a PhD in 1940. He taught briefly at the University of California Berkeley and the University of Michigan before moving to Iowa State University in 1943 and where he was a professor of biochemistry from 1947 to 1954. He was professor of chemistry at Florida State University from 1954 to 1964 when he became director of the Institute of Molecular and Cellular Evolution at the University of Miami. He retired in 1989.

Fox's biochemical research dealt with the study of the origin of life. Fox's research showed that amino acids, when subjected to heat, will spontaneously form polypeptide compounds, Fox dubbed proteinoids (the earlier Miller-Urey experiment had shown that amino acids could have been generated by conditions of the Earth's primordial atmosphere). Fox hypothesized that these poly-amino acid molecules could be the origin the protein molecules that make up living things.  When put into water or salt solution these proteinoids form microspheres, that are one or two microns in diameter. These microspheres behave like cellular membranes, budding off and forming new microspheres. Fox believed that these proteinoid microspheres were the origin of bacterial cell walls. Fox's proteinoid theory for the origin of life has its detractors, who believe that concentrations of the particular amino acids that Fox used in his experiments could not have been present in the primordial environment. Fox was one of the first scientists to examine moon rocks brought back to Earth by NASA.

Fox died on August 10, 1998 in Mobile, Alabama.


References:

Daintith, John; "Fox, Sydney Walter" in Biographical Encyclopedia of Scientists, Third Edition; CRC Press; 2010

"Sydney W Fox, Analyzed First Moon Rocks"; Los Angeles Times; August 18, 1998

Sydney W. Fox Wikipedia Entry

Walter Hess

Walter Rudolf Hess was born on March 17, 1881 in Frauenfeld in the Swiss canton of Thurgau. He was the second of three children on Clemens and Gertrude Hess. His father was a physics teacher in a grammar school and ran a weather station. Hess learned physics from his father and helped the family electrify the family's apartment. He began studying medicine in Lausanne in 1899, finishing his studies in Berlin, Kiel, and Zurich. After passing his qualifying medical exam in Zurich, in 1906, he served as a surgeon's assistant. While a surgeon's assistant he developed a device to measure blood viscosity that was widely used clinically but has been replaced by the measurement of blood sedimentation rate. He was later an ophthalmologists's assistant and then an ophthalmologist. Hess's interest was in physiology and in 1912 he gave up a prosperous practice to take the position of a physiologist's assistant, working under Justus Gaule. In 1916, with Gaule's retirement, Hess first became interim director and then director and professor of the Department of Physiological Institute at the University of Zurich. He remained there until his retirement in 1951.

Hess's physiological studies included the circulatory system, but he is most remembered for his research into brain function. Using a fine tipped electrode he was able to stimulate regions of the mid-brain and develop a map of its functions. Mammalian brains are largely divided three regions: the hindbrain, the midbrain, and the forebrain, moving up from the spinal cord to the head (for a diagram of the brain showing some of the functions of different regions see here). Different regions of the brain have different functions with the hind brain, or brain stem, having body maintenance functions including body temperature, heart and breathing control. The forebrain includes the four lobes of the cerebellum which control thought, memory, and movement. Hess, using his electrode to stimulate regions of the hypothalamus, a region of the mid brain, found that he could stimulate excitement or apathy. He also found regions where he could stimulate hunger and thirst. For his researches he was awarded the 1949 Nobel Prize in medicine and physiology "for his discovery of the functional organization of the interbrain as a coordinator of the activities of the internal organs."

Other honors won by Hess include the Marcel Benoist Prize in 1932 and honorary doctorates from the Universities of Bern, Geneva, and Freiburg and from McGill University.

He died on August 12, 1973.


References:

Hess, C.W.; "Walter Hess (17.3.1881-12.6.1973)"; Schwiezer Archiv fur Neurologie und Psychiatrie (2008)159:259-261

Walter Hess Nobel Biography

Walter Hess Wikipedia Entry

Jeremias B. Richter

Jeremias Benjamin Richter was born on March 10, 1762 in Hirschberg, in Silesia, then part of Prussia, but now part of Poland. He became a mining official in Breslau in 1794 and in 1800 was appointed assessor of the Department of Mines and chemist to the royal porcelain factory in Berlin. He died in Berlin on April 4, 1807.

Richter is most remembered for deducing the law of equivalent proportions. The law of equivalent proportions states that when two or more elements are combined, the weights of these elements are proportional to their equivalent weights, so as such the two are related. This concept, that elements combine in definite ratios to form compounds, is the basis of stoichiometry, a word coined by Richter to describe, "the art of chemical measurements, which has to deal with the laws according to which substances unite to form chemical compounds". This discovery hinted at the existence of atoms, which today we know combine in definite ratios to form compounds.

At the time Richter's work was largely ignored due to his obscure and clumsy writing style and his emphasis on mathematics, which chemists at the time were not interested in. His discoveries were wrongly ascribed to Carl Wenzel and it was not until 1841 when Henri Hess gave Richter proper credit.


References:

Leicester, Henry Marshall and Klickstein, Herbert S.; "Jeremias Benjamin Richter: 1762-1807"; found in A Source Book in Chemistry, 1400-1900; Harvard University Press; 1969

"Richter, Jeremias Benjamin"; Encyclopedia Britannica; 1911

Jeremias Benjamin Richter Wikipedia Entry

Heinrich Lenz

Heinrich Friedrich Emil Lenz was born on February 12, 1804 in Dorpat in the Russian Empire, which is now Tartu, Estonia. He studied theology at the University of Dorpat from 1820 to 1823, but switched to physics. After graduation he served as a scientist with navigator Otto von Kotzebue's third circumnavigation of the world, from 1923 to 1926, where he studied climate and took salinity and specific gravity measurements of sea water. He published several papers based on this trip, and in 1832 published his first paper on electromagnetism. From 1840 to 1863 he was dean of physics at the University of St. Petersburg and he served as rector there from 1863 until his death.

Lenz is most remembered for his studies of electromagnetism. At the beginning of the nineteenth century scientists were beginning to understand electricity and magnetism, but did not understand the relationships between the two. Lenz took one of the first steps in filling in that gap by formulating Lenz's Law. Repeating the work of James Faraday, Lenz observed that when a electrical current is generated by a changing magnetic field, the magnetic field generated by that electrical current opposes the magnetic field that generated the current (see here for a graphic demonstration of this). This result is due to the law of conservation of energy. Lenz's results were copiously documented so that they could be easily repeated and his quantitative results were more thorough than the qualitative work that had been done previous to him.

In addition to Lenz's Law, Lenz also independently discovered Joule's Law and worked on developing electroplating. Lenz is honored by the use of the letter L to represent capacitance in physics equations.

Lenz died on February 10, 1865, in Rome, after suffering a stroke.


References:

Tooker, J.B.; "A Discussion of the Life of Heinrich Friedrich Emil Lenz"; Retrieved from: jtooker.com

National High Magnetic Field Laboratory; "Heinrich Friedrich Emil Lenz (1804-1865)" Retrieved from: magnet.fsu.edu

Heinrich Lenz Wikipedia Entry

Tobias Mayer

Tobias Mayer was born on February 17, 1723 in Marbach a small town on the Neckar river a few miles from Stuttgart. His father was a cart-wright and an engineer who made water systems. When Mayer was young he plagued his mother with requests for paper and writing supplies to copy his father's water system plans. Mayer was orphaned when he was 8 and after a time in an orphanage he was taken on by a shoemaker named Gottlieb Kandler, from whom he learned geometry and architecture. Mayer attended the Latin school in Esslingen where he studied mathematics on his own and reached the top class in two years. He published a book on geometry when he was 18. He attempted to become a artillery officer but circumstances prevented him realizing this goal. He became an excellent map maker and in 1746 he joined the Homann Cartographic Bureau in Nuremberg. In 1751 he was appointed professor of mathematics and economy at the Georg August Academy in Gottingen.

Mayer is mostly remembered for his astronomical observations of the moon. In 1748 and 1749 he made a map of the lunar surface and came to the conclusion that there was no atmosphere on the moon. At the time this was a controversial opinion. His lunar tables, published in 1752, were recommended by the British Astronomer Royal, for their utility in determining longitude while at sea. Mayer's widow received a 3000 pound grant from the British government after bringing them to England.

A crater on the moon is named is named after him. He is often confused with his son, Johann Tobias Mayer, who was a physicist.

Mayer died during the French occupation of Gottingen on February 20, 1762.


References:

Forbes, Eric Gray; "The Life and Work of Tobias Mayer (1723-62)"; Quarterly of the Royal Astronomical Society (1969)8:227-251

Wepster, Steven; "Father and Son Mayer"; Retrieved from staff.science.uu.nl

Tobias Mayer Wikipedia Entry

Victor Hensen

Christian Andreas Victor Hensen was born on February 10, 1835 in Schleswig, which is now part of Germany. His father Hans Hensen was the director of a school for the deaf in Schleswig and his mother, Henriette, was the daughter of the court physician. Hensen graduated from the cathedral school in Schleswig in 1845 and the grammar school at Glukstat, in Holstein in 1854. He studied medicine at the universities of Wurzburg, Berlin, and Kiel, passing his final examination in 1858. In 1859 he completed his thesis on epilepsy and urinary secretions. After finishing his doctorate he worked as a prosector at the University of Kiel. He was appointed professor of physiology in 1871 and he remained there until 1911. In 1867 he became a member of the Prussian House of Representatives. From 1878 he was the director of the institute of physiology at Kiel. In addition to his work on physiology, Henesen was also an oceanographer and lead many oceanographic expeditions.

Hensen's work was involved with many fields of science including physiology, oceanography, and chemistry. His physiological work included describing the structures of the inner ear. These studies led to the discovery of the Hensen duct, Hensen cells and Hensen stripe. These structures and cells are part of the cochlea, the snail shell shaped structure in the inner ear that is responsible for sensing sound waves. Hensen was also able to extract glycogen from the liver and there was a priority dispute about this between him and Claude Bernard. Now it is known that Hensen verified Bernard's work.

Hensen is most remembered for his coining of the word plankton to describe the microscopic sea organisms that form the basis of the ocean's food chain. These organisms include drifting animals, plants, archea, algae, and bacteria. The term plankton describes an ecological niche rather than a specific type of organism. Because they depend on sunlight they are found in greater numbers on the surface of bodies of water. They are found in oceans and lakes and are an important food source for fish and whales. Hensen developed methods of collecting and studying plankton that are still used today.

Hensen died on April 5, 1924.


References:

Press and Communication Services, University of Kiel; "Famous Scholars from Kiel: Victor Hensen"; Retrieved from www.uni-kiel.de

Raica, M.; "A Short Story of Victor Hensen and a Cell of the Inner Ear"; Romanian Journal of Morphology and Embryology (2012)53:855-857

Victor Hensen Wikipedia Entry