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William Nicol (geologist)
William Nicol FRSE FCS (1768?2 September 1851) was a Scottish geologist and physicist who invented the Nicol prism, the first device for obtaining plane-polarized light, in 1828. Early life Nicol was born in Humbie (East Lothian), the son of Walter Nicol and Marion Fowler. According to the parish register, he was born 18 April and baptised on 22 April 1770. Some sources give his date of birth as 1768; other ones (including his gravestone) give 1766. (Note that the gravestone date may be incorrect, as the engraving was done at least 50 years after his death.) Lecturer He started out as aide to his uncle, Henry Moyes, an itinerant lecturer in Natural Philosophy whose blindness necessitated assistance for his chemistry and optics demonstrations.''Joseph Priestley to Joseph Banks'', 6 Feb 1783, NHM, Dawson Turner MS 3, fol. 17p122 Albert Edward Musson, Eric Robinson ''Science and technology in the Industrial Revolution,'' Manchester University Press, 1969, Nicol, having himsel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicol Prism
A Nicol prism is a type of polarizer. It is an optical device made from calcite crystal used to convert ordinary light into plane polarized light. It is made in such a way that it eliminates one of the rays by total internal reflection, i.e. the ordinary ray is eliminated and only the extraordinary ray is transmitted through the prism. It was the first type of polarizing prism, invented in 1828 by William Nicol (1770–1851) of Edinburgh. Mechanism The Nicol prism consists of a rhombohedral crystal of Iceland spar (a variety of calcite) that has been cut at an angle of 68° with respect to the crystal axis, cut again diagonally, and then rejoined, using a layer of transparent Canada balsam as a glue. Unpolarized light ray enters through the side face of the crystal, and is split into two orthogonally polarized, differently directed rays by the birefringence property of calcite. The ''ordinary'' ray, or ''o''-ray, experiences a refractive index of ''n''o = 1.658 in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallelepiped
In geometry, a parallelepiped is a three-dimensional figure formed by six parallelograms (the term ''rhomboid'' is also sometimes used with this meaning). By analogy, it relates to a parallelogram just as a cube relates to a square. Three equivalent definitions of ''parallelepiped'' are *a hexahedron with three pairs of parallel faces, *a polyhedron with six faces (hexahedron), each of which is a parallelogram, and *a prism (geometry), prism of which the base is a parallelogram. The rectangular cuboid (six rectangular faces), cube (six square faces), and the rhombohedron (six rhombus faces) are all special cases of parallelepiped. "Parallelepiped" is now usually pronounced or ; traditionally it was because of its etymology in Ancient Greek, Greek παραλληλεπίπεδον ''parallelepipedon'' (with short -i-), a body "having parallel planes". Parallelepipeds are a subclass of the prismatoids. Properties Any of the three pairs of parallel faces can be viewed as the bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Bryson
Alexander Bryson Fellow of the Royal Society of Edinburgh, FRSE Fellow of the Geological Society of London, FGS FRSSA FSAScot Royal Physical Society of Edinburgh, FRPSE (12 October 1816 – 7 December 1866) was a Scottish biologist, geologist and horologist who served as president of the Royal Scottish Society of Arts (1860–61) and as president of the Royal Physical Society of Edinburgh (1863). Life He was born on 12 October 1816 in Edinburgh, the son of Janet Gillespie (1788-1858) and Robert Bryson FRSE (1778-1852), a watchmaker. He attended the Royal High School, Edinburgh, High School in Edinburgh then trained as a watchmaker and entered the family business, then renamed Robert Bryson & Son. With his first wife, Elizabeth Waterstone Gillespie (possibly a cousin) he had two children who died in infancy, and a daughter and son (William Alexander Bryson) and died 10 April 1855 aged 44. His second wife, Catherine McDonald Cuthbertson, also died young in September 1859, aged ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archibald Geikie
Sir Archibald Geikie (28 December 1835 – November 1924) was a Scottish geologist and writer. Early life Geikie was born in Edinburgh in 1835, the eldest son of Isabella Thom and her husband James Stuart Geikie, a musician and music critic. The elder brother of James Geikie, he was educated at Edinburgh High School and University of Edinburgh. Career In 1855 Geikie was appointed an assistant with the British Geological Survey. Among his early publications for a popular audience was ''The Story of a Boulder; or, Gleanings from the Note-Book of a Geologist'' (1858). His ability at once attracted the notice of his chief, Sir Roderick Murchison, with whom he formed a lifelong friendship, and whose biographer he subsequently became. Geikie completed some early geological mapping with Murchison on complicated regions of schists in the Scottish Highlands; and they jointly published a new geological map of Scotland in 1862. Geikie completed a larger map in 1892. In 1863 he publi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Witham
Henry Thomas Maire Witham FRSE FGS (9 June 1779–1844) was a British landowner remembered as an amateur palaeontologist and mineralogist. He was an early researcher into the internal structure of paleobotany, fossil plants. Life He was born Henry Silvertop, the son of John Silvertop of Minsteracres in Northumberland. His mother was Catherine Lawson of Brough. He was a compulsive gambler and ran up debts of £105,000 (a huge sum in the 1820s) and was forced to sell off much of his property to settle his debts. From 1826 to 1832, he lived in Edinburgh at 14 Great King Street. During his time in Edinburgh (in 1827), he was elected a Fellow of the Royal Society of Edinburgh, his proposer being Thomas Allan (mineralogist), Thomas Allan. Though having no botanical training, he applied William Nicol (geologist), William Nicol's method of examining fossils and rocks under the microscope by slicing them into thin sections. Nicol's first published account of this process is contai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microscope
A microscope () is a laboratory equipment, laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisible to the eye unless aided by a microscope. There are many types of microscopes, and they may be grouped in different ways. One way is to describe the method an instrument uses to interact with a sample and produce images, either by sending a beam of light or electrons through a sample in its optical path, by detecting fluorescence, photon emissions from a sample, or by scanning across and a short distance from the surface of a sample using a probe. The most common microscope (and the first to be invented) is the optical microscope, which uses lenses to refract visible light that passed through a microtome, thinly sectioned sample to produce an observable image. Other major types of microscopes are the fluorescence micro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock (geology)
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the Earth's crust, crust, and most of its interior, except for the liquid Earth's outer core, outer core and pockets of magma in the asthenosphere. The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks. Igneous rocks are formed when magma cools in the Earth's crust, or lava cools on the ground surface or the seabed. Sedimentary rocks are formed by diagenesis and lithification of sediments, which in turn are formed by the weathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystals
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification. The word ''crystal'' derives from the Ancient Greek word (), meaning both "ice" and " rock crystal", from (), "icy cold, frost". Examples of large crystals include snowflakes, diamonds, and table salt. Most inorganic solids are not crystals but polycrystals, i.e. many microscopic crystals fused together into a single solid. Polycrystals include most metals, rocks, ceramics, and ice. A third category of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thin Section
In optical mineralogy and petrography, a thin section (or petrographic thin section) is a thin slice of a rock or mineral sample, prepared in a laboratory, for use with a polarizing petrographic microscope, electron microscope and electron microprobe. A thin sliver of rock is cut from the sample with a diamond saw and ground optically flat. It is then mounted on a glass slide and then ground smooth using progressively finer abrasive grit until the sample is only 30 μm thick. The method uses the Michel-Lévy interference colour chart to determine thickness, typically using quartz as the thickness gauge because it is one of the most abundant minerals. When placed between two polarizing filters set at right angles to each other, the optical properties of the minerals in the thin section alter the colour and intensity of the light as seen by the viewer. As different minerals have different optical properties, most rock forming minerals can be easily identified. Plagioclase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes Physical property, physical and Chemical property, chemical properties, and evaluation of Reactivity (chemistry), chemical reactivity to understand their behavior. The study of organic reactions includes the organic synthesis, chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical (in silico) study. The range of chemicals studied chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular
A molecule is a group of two or more atoms that are held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refraction
In physics, refraction is the redirection of a wave as it passes from one transmission medium, medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and Wind wave, water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed. Optical Prism (optics), prisms and Lens (optics), lenses use refraction to redirect light, as does the human eye. The refractive index of materials varies with the wavelength of light,R. Paschotta, article ochromatic dispersion in th, accessed on 2014-09-08 and thus the angle of the refraction also varies correspondingly. This is called dispersion (optics), dispersion and causes prism (optics), prisms and rainbows to divide white light into its constituent spectral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
