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Johann 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 machine. In 1841 he described the use of the 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 meteorological observer to the Academy of Sciences. Even at this early period he had conceived the idea of founding a physical and chemical scientific journal, and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamburg
(male), (female) en, Hamburger(s), Hamburgian(s) , timezone1 = Central (CET) , utc_offset1 = +1 , timezone1_DST = Central (CEST) , utc_offset1_DST = +2 , postal_code_type = Postal code(s) , postal_code = 20001–21149, 22001–22769 , area_code_type = Area code(s) , area_code = 040 , registration_plate = , blank_name_sec1 = GRP (nominal) , blank_info_sec1 = €123 billion (2019) , blank1_name_sec1 = GRP per capita , blank1_info_sec1 = €67,000 (2019) , blank1_name_sec2 = HDI (2018) , blank1_info_sec2 = 0.976 · 1st of 16 , iso_code = DE-HH , blank_name_sec2 = NUTS Region , blank_info_sec2 = DE6 , website = , footnotes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludwig Wilhelm Gilbert
Ludwig Wilhelm Gilbert (12 August 1769 – 7 March 1824) was a German physicist and chemist, and professor of physics at the University of Leipzig. From 1799-1824 he published the "''Annalen der Physik''", of which Poggendorffs "''Annalen der Physik und Chemie''" was a continuation. Biography Gilbert was born in Berlin. After studying mathematics and geography in the University of Halle, he was appointed as professor in 1795. In 1811, he was appointed as professor of physics at the University of Leipzig Leipzig University (german: Universität Leipzig), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 Decemb ..., and remained in that post until his death. He died in Leipzig. Since 1816 he had been a correspondent of the Royal Institute of the Netherlands. References SourcesLudwig Wilhelm Gilbert 1769 births 1824 deaths 19th- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1877 Deaths
Events January–March * 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 17 – Major General Charles George Gordon of the British Army is appointed Governor-General of the Sudan. * March – ''The Nineteenth Century'' magazine is founded in London. * March 2 – Compromise of 1877: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 to 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 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 Wilson (Harper & Brothers, 191 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Chromic Acid Cell
The Chromic acid cell was a type of primary cell which used chromic acid as a depolarizer. The chromic acid was usually made by acidifying (with sulfuric acid) a solution of potassium dichromate. The old name for potassium dichromate was potassium bichromate and the cell was often called a Bichromate cell.Ayrton, W.E. and Mather, T. ''Practical Electricity'', Cassell and Company, London, 1911, pp 185-187 This type of cell is now only of historical interest. History Construction The main elements of the cell were: * Anode, zinc * Electrolyte, dilute sulfuric acid * Depolarizer, chromic acid * Cathode, carbon The cell was made in two forms - the single-fluid type, attributed to Poggendorff and the two-fluid type, attributed to Fuller. In both cases, cell voltage was about 2 volts. Poggendorff cell The cell was set up in a long-necked glass bottle with a zinc plate located between two carbon plates. The electrolyte and depolarizer were mixed. The mixture would dissolve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, 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 impression that one end of the longer lines is nearer to the viewer than the other end. This is similar to the way the Wundt illusion appears. It may be that the Zöllner illusion is caused by this impression of depth. This illusion is similar to the Hering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 psychical investigator. Biography From 1872 he held the chair of astrophysics at Leipzig University. He wrote numerous papers on photometry and spectrum analysis in Poggendorff's '' 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 shift of absorption lines, via the invention of a very sensitive spectroscope which he named "Reversionspectros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Illusion
Within 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 immerged 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, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valentin Rose (classicist)
Valentin Rose (8 January 1829 in Berlin – 25 December 1916 in Berlin) was a German classicist and textual critic. Personal life Valentin Rose was the son of mineralogist Gustav Rose (1798–1873), and a nephew to famed mineralogist Heinrich Rose (1795–1864) and to the pharmacist Wilhelm Rose (1792–1867), of whom he published a brief remembranceBerlin 1867. His great-grandfather was pharmacologist Valentin Rose the Elder (1736–1771), and his grandfather was Valentin Rose the Younger (1762–1807), who was also a noted pharmacologist. His younger brother was the surgeon Edmund Rose. In August 1872 he married Marie Poggendorff, the daughter of Johann Christian Poggendorff. Academic career Rose received his doctorate from the Friedrich-Wilhelms-Universität in Berlin in 1854. In 1855, he took a post at the Royal Library at Berlin, where he remained until his retirement in 1905. Under his leadership, the library's Manuscript Department (which he headed from 1886), gaine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
