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Johann Christian Poggendorff
Johann Christian Poggendorff (29 December 1796 – 24 January 1877) was a German physicist born in Hamburg. By far the greater and more important part of his work related to electricity and magnetism. Poggendorff is known for his electrostatic motor which is analogous to Wilhelm Holtz's electrostatic generator, electrostatic machine. In 1841 he described the use of the potentiometer (measuring instrument), potentiometer for measurement of electrical potentials without current draw. Biography Poggendorf had apprenticed himself to an apothecary in Hamburg, and when twenty-two began to earn his living as an apothecary's assistant at Itzehoe. Ambition and a strong inclination towards a scientific career led him to throw up his business and move to Berlin, where he entered Humboldt University in 1820. Here his abilities were speedily recognized, and in 1823 he was appointed meteorology, meteorological observer to the Academy of Sciences. Even at this early period he had conceived the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hamburg
Hamburg (, ; ), officially the Free and Hanseatic City of Hamburg,. is the List of cities in Germany by population, second-largest city in Germany after Berlin and List of cities in the European Union by population within city limits, 7th-largest in the European Union with a population of over 1.9 million. The Hamburg Metropolitan Region has a population of over 5.1 million and is the List of EU metropolitan areas by GDP, eighth-largest metropolitan region by GDP in the European Union. At the southern tip of the Jutland Peninsula, Hamburg stands on the branching River Elbe at the head of a estuary to the North Sea, on the mouth of the Alster and Bille (Elbe), Bille. Hamburg is one of Germany's three city-states alongside Berlin and Bremen (state), Bremen, and is surrounded by Schleswig-Holstein to the north and Lower Saxony to the south. The Port of Hamburg is Germany's largest and Europe's List of busiest ports in Europe, third-largest, after Port of Rotterdam, Rotterda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Meteorology
Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agriculture, construction, weather warnings and disaster management. Along with climatology, atmospheric physics and atmospheric chemistry, meteorology forms the broader field of the atmospheric sciences. The interactions between Earth's atmosphere and its oceans (notably El Niño and La Niña) are studied in the interdisciplinary field of hydrometeorology. Other interdisciplinary areas include biometeorology, space weather and planetary meteorology. Marine weather forecasting relates meteorology to maritime and coastal safety, based on atmospheric interactions with large bodies of water. Meteorologists study meteorological phenomena driven by solar radiation, Earth's rotation, ocean currents and other factors. These include everyday ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
1877 Deaths
Events January * January 1 – Queen Victoria is proclaimed Empress of India by the Royal Titles Act 1876, introduced by Benjamin Disraeli, the Prime Minister of the United Kingdom . * January 8 – Great Sioux War of 1876: Battle of Wolf Mountain – Crazy Horse and his warriors fight their last battle with the United States Cavalry in Montana. * January 20 – The Conference of Constantinople ends, with Ottoman Turkey rejecting proposals of internal reform and Balkan provisions. * January 29 – The Satsuma Rebellion, a revolt of disaffected samurai in Japan, breaks out against the new imperial government; it lasts until September, when it is crushed by a professionally led army of draftees. February * February 17 – Major General Charles George Gordon of the British Army is appointed Governor-General of the Sudan. March * March 2 – Compromise of 1877: The 1876 United States presidential election is resolved with the selection of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
1796 Births
Events January–March * January 16 – The first Dutch (and general) elections are held for the National Assembly of the Batavian Republic. (The next Dutch general elections are held in 1888.) * February 1 – The capital of Upper Canada is moved from Newark, Upper Canada, Newark to York, Upper Canada, York. * February 9 – The Qianlong Emperor of China abdicates at age 84 to make way for his son, the Jiaqing Emperor. * February 15 – French Revolutionary Wars: The Invasion of Ceylon (1795) ends when Johan van Angelbeek, the Batavian Republic, Batavian governor of Ceylon, surrenders Colombo peacefully to British forces. * February 16 – The Kingdom of Great Britain is granted control of Ceylon by the Dutch. * February 29 – Ratifications of the Jay Treaty between Great Britain and the United States are officially exchanged, bringing it into effect.''Harper's Encyclopaedia of United States History from 458 A. D. to 1909'', ed. by Benson John Lossing and, Woodrow Wils ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Emil Frommel
Emil Frommel (1828–1896) was a German pastor and author, born at Karlsruhe. He studied at Halle upon Saale, Erlangen, and Heidelberg, held several pastorates, served as army chaplain in the Franco-German War of 1870–1871 and in 1872 was appointed court preacher at Berlin and pastor of the garrison in that city. Life Emil Frommel was born on 5 January 1828 at Karlsruhe in the then Grand Duchy of Baden, Southern Germany. His father was director of the ducal art gallery. He studied theology at the universities of Halle, Erlangen, and Heidelberg before being appointed as vicar in Alt-Lussheim, near Schwetzingenin 1850. Four years later, he became vicar in his hometown and this was followed by a move in 1864 to Barmen in Westphalia. His next appointment, in 1869, was as pastor in the Garnisonkirche in Berlin. His role as a field chaplain meant that he travelled to France with the army when the Franco-Prussian War began in the following summer. He marked the German victory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Chromic Acid Cell
The chromic acid cell is a type of primary cell which uses chromic acid as a depolarizer. The chromic acid is usually made by acidifying (with sulfuric acid) a solution of potassium dichromate. The old name for potassium dichromate is potassium bichromate and the cell is often called a bichromate cell. This type of cell is now only of historical interest. History Construction The main elements of the cell are: * Anode, zinc * Electrolyte, dilute sulfuric acid * Depolarizer, chromic acid * Cathode, carbon The cell is made in two forms - the single-fluid type, attributed to Poggendorff and the two-fluid type, attributed to Fuller. In both cases, cell voltage is about 2 volts. Poggendorff cell The cell is set up in a long-necked glass bottle with a zinc plate located between two carbon plates. The electrolyte and depolarizer are then mixed. The mixture would dissolve the zinc plate even when the cell is not in use, so there is a mechanism for lifting the zinc plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Zöllner Illusion
The Zöllner illusion is an optical illusion named after its discoverer, German astrophysicist Johann Karl Friedrich Zöllner. In 1860, Zöllner sent his discovery in a letter to physicist and scholar Johann Christian Poggendorff Johann Christian Poggendorff (29 December 1796 – 24 January 1877) was a German physicist born in Hamburg. By far the greater and more important part of his work related to electricity and magnetism. Poggendorff is known for his electrostatic mo ..., editor of '' Annalen der Physik und Chemie'', who subsequently discovered the related Poggendorff illusion in Zöllner's original drawing. One depiction of the illusion consists of a series of parallel, black diagonal lines which are crossed with short, repeating lines, the direction of the crossing lines alternating between horizontal and vertical. This creates the illusion that the black lines are not parallel. The shorter lines are on an angle to the longer lines, and this angle helps to create the im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Johann Karl Friedrich Zöllner
Johann Karl Friedrich Zöllner (8 November 1834, Berlin25 April 1882, Leipzig) was a German astrophysicist who studied optical illusions. He was also an early Parapsychology, psychical investigator. Biography From 1872 he held the chair of astrophysics at Leipzig University. He wrote numerous papers on photometry and spectrum analysis in Johann Christian Poggendorff, Poggendorff's ''Annalen der Physik, Annalen'' and ''Berichte der k. sächsischen Gesellschaft der Wissenschaften'', two works on celestial photometry (''Grundzüge einer allgemeinen Photometrie des Himmels'', Berlin, 1861, 4to, and ''Photometrische Untersuchungen'', Leipzig, 1865, 8vo), and a curious book, ''Ueber die Natur der Cometen'' (Leipzig, 1872, 3rd ed. 1883). He discovered the Zöllner illusion where lines that are parallel appear diagonal. He also successfully proved Christian Doppler's theory on the effect of motion of the color of stars, and the resulting red-shift, shift of absorption lines, via the inve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Optical Illusion
In visual perception, an optical illusion (also called a visual illusion) is an illusion caused by the visual system and characterized by a visual perception, percept that arguably appears to differ from reality. Illusions come in a wide variety; their categorization is difficult because the underlying cause is often not clear but a classification proposed by Richard Gregory is useful as an orientation. According to that, there are three main classes: physical, physiological, and cognitive illusions, and in each class there are four kinds: Ambiguities, distortions, paradoxes, and fictions. A classical example for a physical distortion would be the apparent bending of a stick half immersed in water; an example for a physiological paradox is the motion aftereffect (where, despite movement, position remains unchanged). An example for a physiological fiction is an afterimage. Three typical cognitive distortions are the Ponzo illusion, Ponzo, Poggendorff illusion, Poggendorff, and M� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Poggendorff Illusion
The Poggendorff illusion is a geometrical-optical illusion that involves the misperception of the position of one segment of a transverse line that has been interrupted by the contour of an intervening structure. It is named after Johann Christian Poggendorff, the editor of the journal, who discovered it in the figures Johann Karl Friedrich Zöllner submitted when first reporting on what is now known as the Zöllner illusion, in 1860.Although Zöllner was focused on a different illusion, the misalignment of the diagonal lines revealed a distinct visual phenomenon. The Poggendorff illusion has become a widely studied example of spatial misperception in vision science and psychology. It has been used to investigate theories of perceptual systems, neurological function, and cognitive development. The magnitude of the illusion depends on the properties of the obscuring pattern and the nature of its borders.Many detailed studies of the illusion, including "amputating" various components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Royal Swedish Academy Of Sciences
The Royal Swedish Academy of Sciences () is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for promoting natural sciences and mathematics and strengthening their influence in society, whilst endeavouring to promote the exchange of ideas between various disciplines. The goals of the academy are: * To be a forum where researchers meet across subject boundaries, * To offer a unique environment for research, * To provide support to younger researchers, * To reward outstanding research efforts, * To communicate internationally among scientists, * To advance the case for science within society and to influence research policy priorities * To stimulate interest in mathematics and science in school, and * To disseminate and popularize scientific information in various forms. Every year, the academy awards the Nobel Prizes in Nobel Prize in Physics, phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
