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Émile Bertrand
Émile Bertrand (1844–1909) was a French mineralogist, in honour of whom bertrandite was named by Alexis Damour. He also gave his name to the ''Bertrand lens'' or phase telescope. He studied at the Ecole des Mines in Paris and was a co-founder of the . He wrote a book on the application of microscopy to mineralogical studies, "''De l'Application du microscope à l'étude de la minéralogie''" (1878); published a translation of Ernst Mach's work on the history of mechanics, "''La mécanique: exposé historique et critique de son développement''" (1904); and is credited with the design of a refractometer A refractometer is a laboratory or field device for the measurement of an Refractive index, index of refraction (refractometry). The index of refraction is calculated from the observed refraction angle using Snell's law. For mixtures, the index .... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineralogist
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical mineralogy, optical) properties of minerals and mineralized artifact (archaeology), artifacts. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization. History Early writing on mineralogy, especially on gemstones, comes from ancient Babylonia, the ancient Greco-Roman world, ancient and medieval History of China, China, and Sanskrit texts from History of India, ancient India and the ancient Islamic world. Books on the subject included the ''Naturalis Historia, Natural History'' of Pliny the Elder, which not only described many different minerals but also explained many of their properties, and Kitab al Jawahir (Book of Precious Stones) by Persian scientist Al-Biruni. The German Renaissance specialist Georgius Agricola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bertrandite
Bertrandite is a beryllium sorosilicate hydroxide mineral with composition: Be4Si2O7(OH)2. Bertrandite is a colorless to pale yellow orthorhombic mineral with a hardness of 6–7. It is commonly found in beryllium rich pegmatites and is in part an alteration of beryl. Bertrandite often occurs as a pseudomorphic replacement of beryl. Associated minerals include beryl, phenakite, herderite, tourmaline, muscovite, fluorite and quartz. It, with beryl, are ores of beryllium. It was discovered near Nantes, France in 1883 and named after French mineralogist, Emile Bertrand (1844–1909). One of the world's largest deposits of bertrandite is Spor Mountain, Thomas Range, Utah which is currently the source of most of the world's beryllium production. See also *List of minerals *List of minerals named after people This is a list of minerals named after people. The chemical composition of the mineral follows the name. A * Abelsonite: – American physicist Philip Hauge Abe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexis Damour
Augustin Alexis Damour (19 July 1808, in Paris Р22 September 1902, in Paris) was a French mineralogist who was also interested in prehistory. Biography In 1827 he studied under Alexandre Brongniart at the Mus̩um d'Histoire Naturelle in Paris, and up until 1854, worked for the Ministry of Foreign Affairs and International Development (France), Minist̬re des affaires ̩trang̬res. Afterwards, he devoted himself to mineralogical research, achieving fame for his research involving the chemical composition of many different minerals.The Mineralogical Record Augustin Alexis Damour Collection (biography)Prosopo Soci̩t̩s savantes de France In addition to his solo analyses of various minerals, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Telescope
A phase telescope or Bertrand lens is an optical device used in aligning the various optical components of a light microscope. In particular it allows observation of the back focal plane of the objective lens and its conjugated focal planes. The phase telescope/Bertrand lens is inserted into the microscope in place of an eyepiece to move the intermediate image plane to a point where it can be observed. Phase telescopes are primarily used for aligning the optical components required for Köhler illumination and phase contrast microscopy. For Köhler illumination the light source and condenser diaphragm should appear in focus at the back focal plane of the objective lens. For phase contrast microscopy the phase ring (at the back focal plane of the objective) and the annulus (at the back focal plane of the condenser lens) should appear in focus and in alignment. Bertrand lenses find use in creating interference figures and assisting in aligning a microscope to generate interference fig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mines ParisTech
Mine, mines, miners or mining may refer to: Extraction or digging *Miner, a person engaged in mining or digging *Mining, extraction of mineral resources from the ground through a mine Grammar *Mine, a first-person English possessive pronoun Military * Mining (military), digging under a fortified military position to penetrate its defenses * Mine warfare ** Anti-tank mine, a land mine made for use against armored vehicles ** Antipersonnel mine, a land mine targeting people walking around, either with explosives or poison gas ** Bangalore mine, colloquial name for the Bangalore torpedo, a man-portable explosive device for clearing a path through wire obstacles and land mines ** Cluster bomb, an aerial bomb which releases many small submunitions, which often act as mines ** Land mine, explosive mines placed under or on the ground ** Naval mine, or sea mine, a mine at sea, either floating or on the sea bed, often dropped via parachute from aircraft, or otherwise lain by surfac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paris
Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of cities in the European Union by population within city limits, fourth-most populous city in the European Union and the List of cities proper by population density, 30th most densely populated city in the world in 2022. Since the 17th century, Paris has been one of the world's major centres of finance, diplomacy, commerce, culture, Fashion capital, fashion, and gastronomy. Because of its leading role in the French art, arts and Science and technology in France, sciences and its early adoption of extensive street lighting, Paris became known as the City of Light in the 19th century. The City of Paris is the centre of the ÃŽle-de-France region, or Paris Region, with an official estimated population of 12,271,794 inhabitants in January 2023, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microscopy
Microscopy is the technical field of using microscopes to view subjects too small to 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 microscopy: optical microscope, optical, electron microscope, electron, and scanning probe microscopy, along with the emerging field of X-ray microscopy. Optical microscopy and electron microscopy involve the diffraction, reflection (physics), reflection, or refraction of electromagnetic radiation/electron beams interacting with the Laboratory specimen, specimen, and the collection of the scattered radiation or another signal in order to create an image. This process may be carried out by wide-field irradiation of the sample (for example standard light microscopy and transmission electron microscope, transmission electron microscopy) or by scanning a fine beam over the sample (for example confocal laser scanning microscopy and scanning electron microscopy). Scan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Mach
Ernst Waldfried Josef Wenzel Mach ( ; ; 18 February 1838 – 19 February 1916) was an Austrian physicist and philosopher, who contributed to the understanding of the physics of shock waves. The ratio of the speed of a flow or object to that of sound is named the Mach number in his honour. As a philosopher of science, he was a major influence on logical positivism and American pragmatism. Through his criticism of Isaac Newton's theories of space and time, he foreshadowed Albert Einstein's theory of relativity. Biography Early life Mach was born in Chrlice (), Moravia, Austrian Empire (now part of Brno in the Czech Republic). His father Jan Nepomuk Mach, who had graduated from Charles-Ferdinand University in Prague, acted as tutor to the noble Brethon family in ZlÃn in eastern Moravia. His grandfather, Wenzl Lanhaus, an administrator of the Chirlitz estate, was also master builder of the streets there. His activities in that field later influenced Ernst Mach's theoretical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractometer
A refractometer is a laboratory or field device for the measurement of an Refractive index, index of refraction (refractometry). The index of refraction is calculated from the observed refraction angle using Snell's law. For mixtures, the index of refraction then allows the concentration to be determined using mixing rules such as the Gladstone–Dale relation and Clausius–Mossotti_relation#Lorentz–Lorenz_equation, Lorentz–Lorenz equation. Refractometry Standard refractometers measure the extent of light refraction (as part of a refractive index) of transparent substances in either a liquid this is then used in order to identify a liquid sample, analyze the sample's purity, and determine the amount or concentration of dissolved substances within the sample. As light passes through the liquid from the air it will slow down and create a ‘bending’ illusion, the severity of the ‘bend’ will depend on the amount of substance dissolved in the liquid. For example, the am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1844 Births
In the Philippines, 1844 had only 365 days, when Tuesday, December 31 was skipped as Monday, December 30 was immediately followed by Wednesday, January 1, 1845, the next day after. The change also applied to Caroline Islands, Guam, Marianas Islands, Marshall Islands and Palau as part of the Captaincy General of the Philippines; these became the first places on Earth to redraw the International Date Line. Events January–March * January 4 – The first issue of the Swedish-languaged ''Saima'' newspaper founded by J. V. Snellman is published in Kuopio, Finland. * January 15 – The University of Notre Dame, based in the city of the same name, receives its charter from Indiana. * February 27 – The Dominican Republic gains independence from Haiti. * February 28 – A gun on the USS ''Princeton'' explodes while the boat is on a Potomac River cruise, killing U.S. Secretary of State Abel Upshur, U.S. Secretary of the Navy Thomas Walker Gilmer and four other people. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1909 Deaths
Events January–February * January 4 – Explorer Aeneas Mackintosh of the Imperial Trans-Antarctic Expedition escapes death by fleeing across drift ice, ice floes. * January 7 – Colombia recognizes the independence of Panama. * January 9 – The British Nimrod Expedition, ''Nimrod'' Expedition to the South Pole, led by Ernest Shackleton, arrives at the Farthest South, farthest south reached by any prior expedition, at 88°23' S, prior to turning back due to diminishing supplies. * January 11 – The International Joint Commission on US-Canada boundary waters is established. * January 16 – Members of the ''Nimrod'' Expedition claim to have found the magnetic South Pole (but the location recorded may be incorrect). * January 24 – The White Star Liner RMS Republic (1903), RMS ''Republic'' sinks the day after a collision with ''SS Florida'' off Nantucket. Almost all of the 1,500 passengers are rescued. * January 28 – The last United States t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
