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Ultramarine was the finest and most expensive blue used by Renaissance painters. It was often used for the robes of the Virgin Mary and symbolized holiness and humility. It remained an extremely expensive pigment until a synthetic ultramarine was invented in 1826. [7] Ultramarine is a permanent pigment when under ideal preservation conditions.
Full-text search. In text retrieval, full-text search refers to techniques for searching a single computer -stored document or a collection in a full-text database. Full-text search is distinguished from searches based on metadata or on parts of the original texts represented in databases (such as titles, abstracts, selected sections, or ...
William Henry Perkin. Sir William Henry Perkin FRS (12 March 1838 – 14 July 1907) [ 1] was a British chemist and entrepreneur best known for his serendipitous discovery of the first commercial synthetic organic dye, mauveine, made from aniline. Though he failed in trying to synthesise quinine for the treatment of malaria, he became successful ...
27 April – ending of the First Anglo-Ashanti War (1823–1831). 28 April–1 June – general election results in a Whig victory, and a mandate for electoral reform. [3] May–June – Merthyr Rising in Merthyr Tydfil. 30 May – census in the United Kingdom. 1 June – Royal Navy officer and explorer James Clark Ross leads the first ...
The Purple Earth Hypothesis (PEH) is an astrobiological hypothesis, first proposed by molecular biologist Shiladitya DasSarma in 2007, [ 1] that the earliest photosynthetic life forms of Early Earth were based on the simpler molecule retinal rather than the more complex porphyrin -based chlorophyll, making the surface biosphere appear purplish ...
Purple has long been associated with royalty, originally because Tyrian purple dye—made from the secretions of sea snails—was extremely expensive in antiquity. [1] Purple was the color worn by Roman magistrates; it became the imperial color worn by the rulers of the Byzantine Empire and the Holy Roman Empire , and later by Roman Catholic ...
Gold often occurs in free elemental ( native state ), as nuggets or grains, in rocks, veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as in electrum ), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite.
The evolution of photosynthesis refers to the origin and subsequent evolution of photosynthesis, the process by which light energy is used to assemble sugars from carbon dioxide and a hydrogen and electron source such as water. It is believed that the pigments used for photosynthesis initially were used for protection from the harmful effects ...