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Jonathan Sisson
Jonathan Sisson (1690 – 1747) was a prominent English instrument maker, the inventor of the modern theodolite with a sighting telescope for surveying, and a leading maker of astronomical instruments. Career Jonathan Sisson was born in Lincolnshire around 1690. He was apprenticed to George Graham (1673–1751), then became independent in 1722. He remained an associate of Graham and of the instrument maker John Bird (1709–1776). All three were recommended by the Royal Society and received some funding from the state, which recognised the value of instruments both to the Royal Navy and to merchant ships. After striking out on his own in 1722 and opening a business in the Strand in London, Sisson gained a reputation for making highly accurate arcs and circles, and for the altazimuth theodolites that he made to his own design. He became a well-known maker of optical and mathematical instruments. In 1729 Sisson was appointed mathematical instrument maker to Frederick, Prince of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brackets
A bracket is either of two tall fore- or back-facing punctuation marks commonly used to isolate a segment of text or data from its surroundings. Typically deployed in symmetric pairs, an individual bracket may be identified as a 'left' or 'right' bracket or, alternatively, an "opening bracket" or "closing bracket", respectively, depending on the Writing system#Directionality, directionality of the context. Specific forms of the mark include parentheses (also called "rounded brackets"), square brackets, curly brackets (also called 'braces'), and angle brackets (also called 'chevrons'), as well as various less common pairs of symbols. As well as signifying the overall class of punctuation, the word "bracket" is commonly used to refer to a specific form of bracket, which varies from region to region. In most English-speaking countries, an unqualified word "bracket" refers to the parenthesis (round bracket); in the United States, the square bracket. Glossary of mathematical sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Province Of New York
The Province of New York (1664–1776) was a British proprietary colony and later royal colony on the northeast coast of North America. As one of the Middle Colonies, New York achieved independence and worked with the others to found the United States. In 1664, the Dutch Province of New Netherland in America was awarded by Charles II of England to his brother James, Duke of York. James raised a fleet to take it from the Dutch and the Governor surrendered to the English fleet without recognition from the Dutch West Indies Company that had authority over it. The province was renamed for the Duke of York, as its proprietor. England seized ''de facto'' control of the colony from the Dutch in 1664, and was given ''de jure'' sovereign control in 1667 in the Treaty of Breda and again in the Treaty of Westminster (1674). It was not until 1674 that English common law was applied in the colony. The colony was one of the Middle Colonies, and ruled at first directly from England. Wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vernier Scale
A vernier scale, named after Pierre Vernier, is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation, thereby increasing resolution and reducing measurement uncertainty by using vernier acuity to reduce human estimation error. It may be found on many types of instrument measuring linear or angular quantities, but in particular on a vernier caliper which measures internal or external diameter of hollow cylinders. The vernier is a subsidiary scale replacing a single measured-value pointer, and has for instance ten divisions equal in distance to nine divisions on the main scale. The interpolated reading is obtained by observing which of the vernier scale graduations is coincident with a graduation on the main scale, which is easier to perceive than visual estimation between two points. Such an arrangement can go to a higher resolution by using a higher scale ratio, known as the vernier constant. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic North
The north magnetic pole, also known as the magnetic north pole, is a point on the surface of Earth's Northern Hemisphere at which the planet's magnetic field points vertically downward (in other words, if a magnetic compass needle is allowed to rotate in three dimensions, it will point straight down). There is only one location where this occurs, near (but distinct from) the geographic north pole. The geomagnetic north pole is the northern antipodal pole of an ideal dipole model of the Earth's magnetic field, which is the most closely fitting model of Earth's actual magnetic field. The north magnetic pole moves over time according to magnetic changes and flux lobe elongation in the Earth's outer core. In 2001, it was determined by the Geological Survey of Canada to lie west of Ellesmere Island in northern Canada at . It was situated at in 2005. In 2009, while still situated within the Canadian Arctic at , it was moving toward Russia at between per year. As of 2021, the po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirit Level
A spirit level, bubble level, or simply a level, is an instrument designed to indicate whether a surface is horizontal (level) or vertical (plumb). Different types of spirit levels may be used by carpenters, stonemasons, bricklayers, other building trades workers, surveyors, millwrights and other metalworkers, and in some photographic or videographic work. Construction Early tubular spirit levels had very slightly curved glass vials with constant inner diameter at each viewing point. These vials are incompletely filled with a liquid, usually a colored spirit or alcohol, leaving a bubble in the tube. They have a slight upward curve, so that the bubble naturally rests in the center, the highest point. At slight inclinations the bubble travels away from the marked center position. Where a spirit level must also be usable upside-down or on its side, the curved constant-diameter tube is replaced by an uncurved barrel-shaped tube with a slightly larger diameter in its middle. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonard Digges (scientist)
Leonard Digges (c.1515 – c.1559) was a well-known English mathematician and surveyor, credited with the invention of the theodolite, and a great populariser of science through his writings in English on surveying, cartography, and military engineering. His birth date is variously suggested as c.1515. or c.1520 (but certainly by 1530). Much of his work was expanded on, annotated, and published by his son, Thomas Digges. His son followed in his footsteps and was a pivotal player in the popularisation of Copernicus's book ''De revolutionibus orbium coelestium''. Notes written by Thomas Digges in the publication of the book ''Pantometria'' in 1570 contain descriptions of how Leonard Digges made use of a "''proportional Glass''" to view distant objects and people. Some, such as astronomer and historian Colin Ronan, claim this describes a reflecting or refracting telescope built between 1540 and 1559, but its vague description and claimed performance makes it dubious. Biography Leona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Grundy, Sr
John is a common English name and surname: * John (given name) * John (surname) John may also refer to: New Testament Works * Gospel of John, a title often shortened to John * First Epistle of John, often shortened to 1 John * Second Epistle of John, often shortened to 2 John * Third Epistle of John, often shortened to 3 John People * John the Baptist (died c. AD 30), regarded as a prophet and the forerunner of Jesus Christ * John the Apostle (lived c. AD 30), one of the twelve apostles of Jesus * John the Evangelist, assigned author of the Fourth Gospel, once identified with the Apostle * John of Patmos, also known as John the Divine or John the Revelator, the author of the Book of Revelation, once identified with the Apostle * John the Presbyter, a figure either identified with or distinguished from the Apostle, the Evangelist and John of Patmos Other people with the given name Religious figures * John, father of Andrew the Apostle and Saint Peter * Pope J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Level
A level is an optical instrument used to establish or verify points in the same horizontal plane in a process known as ''levelling''. It is used in conjunction with a levelling staff to establish the relative height or levels (the vertical separation) of objects or marks. It is widely used in surveying and construction to measure height differences and to transfer, measure, and set heights of known objects or marks. It is also known as a surveyor's level, builder's level, dumpy level or the historic "Y" level. It operates on the principle of establishing a visual level relationship between two or more points, for which an inbuilt optical telescope and a highly accurate bubble level are used to achieve the necessary accuracy. Traditionally the instrument was completely adjusted manually to ensure a level line of sight, but modern automatic versions self-compensate for slight errors in the coarse levelling of the instrument, and are thereby quicker to use. The optical level sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Watt
James Watt (; 30 January 1736 (19 January 1736 OS) – 25 August 1819) was a Scottish inventor, mechanical engineer, and chemist who improved on Thomas Newcomen's 1712 Newcomen steam engine with his Watt steam engine in 1776, which was fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world. While working as an instrument maker at the University of Glasgow, Watt became interested in the technology of steam engines. He realised that contemporary engine designs wasted a great deal of energy by repeatedly cooling and reheating the cylinder. Watt introduced a design enhancement, the separate condenser, which avoided this waste of energy and radically improved the power, efficiency, and cost-effectiveness of steam engines. Eventually, he adapted his engine to produce rotary motion, greatly broadening its use beyond pumping water. Watt attempted to commercialise his invention, but experienced great financial di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be transformed, by a connecting rod and crank, into rotational force for work. The term "steam engine" is generally applied only to reciprocating engines as just described, not to the steam turbine. Steam engines are external combustion engines, where the working fluid is separated from the combustion products. The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In general usage, the term ''steam engine'' can refer to either complete steam plants (including boilers etc.), such as railway steam locomotives and portable engines, or may refer to the piston or turbine machinery alone, as in the beam engine and stationary steam engine. Although steam-driven devices were known as early as the aeolipile in the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Newcomen
Thomas Newcomen (; February 1664 – 5 August 1729) was an English inventor who created the atmospheric engine, the first practical fuel-burning engine in 1712. He was an ironmonger by trade and a Baptist lay preacher by calling. He was born in Dartmouth, in Devon, England, to a merchant family and baptised at St. Saviour's Church on 28 February 1664. In those days flooding in coal and tin mines was a major problem. Newcomen was soon engaged in trying to improve ways to pump out the water from such mines. His ironmonger's business specialised in designing, manufacturing and selling tools for the mining industry. Religious life Thomas Newcomen was a lay preacher and a teaching elder in the local Baptist church. After 1710 he became the pastor of a local group of Baptists. His father had been one of a group who brought the well-known Puritan John Flavel to Dartmouth. Later one of Newcomen's business contacts in London, Edward Wallin, was another Baptist minister who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
