Lead is a chemical element with atomic number 82 and symbol Pb. When freshly cut, it is bluish-white, it tarnishes to a dull gray upon exposure to air and it is a soft and heavy metal with a density exceeding that of most common materials. Lead has the second-highest atomic number of the stable elements. Lead is a relatively unreactive post-transition metal and its weak metallic character is illustrated by its amphoteric nature and tendency to form covalent bonds. Compounds of lead are found in the +2 oxidation state. Exceptions are mostly limited to organolead compounds, like the lighter members of the group, lead exhibits a tendency to bond to itself, it can form chains and polyhedral structures. Lead is easily extracted from its ores and was known to people in Western Asia. A principal ore of lead, often bears silver, Lead production declined after the fall of Rome and did not reach comparable levels again until the Industrial Revolution. Nowadays, global production of lead is about ten million tonnes annually, Lead has several properties that make it useful, high density, low melting point and relative inertness to oxidation.
In the late 19th century, lead was recognized as poisonous, Lead is a neurotoxin that accumulates in soft tissues and bones, damaging the nervous system and causing brain disorders and, in mammals, blood disorders. A lead atom has 82 electrons, arranged in a configuration of 4f145d106s26p2. The combined first and second ionization energies—the total energy required to remove the two 6p electrons—is close to that of tin, leads upper neighbor in group 14. This is unusual since ionization energies generally fall going down a group as an elements outer electrons become more distant from the nucleus, the similarity is caused by the lanthanide contraction—the decrease in element radii from lanthanum to lutetium, and the relatively small radii of the elements after hafnium. The contraction is due to shielding of the nucleus by the lanthanide 4f electrons. The combined first four ionization energies of lead exceed those of tin, for this reason lead, unlike tin, mostly forms compounds in which it has an oxidation state of +2, rather than +4.
Relativistic effects, which become particularly prominent at the bottom of the periodic table, as a result, the 6s electrons of lead become reluctant to participate in bonding, a phenomenon called the inert pair effect. A related outcome is that the distance between nearest atoms in crystalline lead is unusually long, the lighter group 14 elements form stable or metastable allotropes having the tetrahedrally coordinated and covalently bonded diamond cubic structure. The energy levels of their outer s- and p-orbitals are close enough to allow mixing into four hybrid sp3 orbitals
The slide rule, known colloquially in the United States as a slipstick, is a mechanical analog computer. The slide rule is used primarily for multiplication and division, and for functions such as exponents, roots and trigonometry, though similar in name and appearance to a standard ruler, the slide rule is not ordinarily used for measuring length or drawing straight lines. Slide rules exist in a range of styles and generally appear in a linear or circular form with a standardized set of markings essential to performing mathematical computations. Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in calculations common to those fields, at its simplest, each number to be multiplied is represented by a length on a sliding ruler. As the rulers each have a scale, it is possible to align them to read the sum of the logarithms. The Reverend William Oughtred and others developed the rule in the 17th century based on the emerging work on logarithms by John Napier.
Before the advent of the calculator, it was the most commonly used calculation tool in science. In its most basic form, the slide rule uses two logarithmic scales to allow rapid multiplication and division of numbers and these common operations can be time-consuming and error-prone when done on paper. More elaborate slide rules allow other calculations, such as roots, logarithms. Scales may be grouped in decades, which are numbers ranging from 1 to 10. Thus single decade scales C and D range from 1 to 10 across the width of the slide rule while double decade scales A and B range from 1 to 100 over the width of the slide rule. Numbers aligned with the marks give the value of the product, quotient. The user determines the location of the point in the result. Scientific notation is used to track the decimal point in more formal calculations and subtraction steps in a calculation are generally done mentally or on paper, not on the slide rule. Most slide rules consist of three strips of the same length, aligned in parallel and interlocked so that the central strip can be moved lengthwise relative to the other two.
The outer two strips are fixed so that their relative positions do not change. Some slide rules have scales on both sides of the rule and slide strip, others on one side of the outer strips and both sides of the slide strip, still others on one side only. A sliding cursor with a vertical alignment line is used to find corresponding points on scales that are not adjacent to other or
Robinson Crusoe /ˌrɒbɪnsən ˈkruːsoʊ/ is a novel by Daniel Defoe, first published on 25 April 1719. The first edition credited the works protagonist Robinson Crusoe as its author, leading readers to believe he was a real person. Despite its simple style, Robinson Crusoe was well received in the literary world and is often credited as marking the beginning of realistic fiction as a literary genre. It is generally seen as a contender for the first English novel, Crusoe sets sail from the Queens Dock in Hull on a sea voyage in August 1651, against the wishes of his parents, who want him to pursue a career, possibly in law. After a tumultuous journey where his ship is wrecked in a storm and this journey, ends in disaster, as the ship is taken over by Salé pirates and Crusoe is enslaved by a Moor. Two years later, he escapes in a boat with a boy named Xury, the ship is en route to Brazil. Crusoe sells Xury to the captain, with the captains help, Crusoe procures a plantation. He observes the latitude as 9 degrees and 22 minutes north and he sees penguins and seals on his island.
As for his arrival there, only he and three animals, the dog and two cats, survive the shipwreck. Overcoming his despair, he fetches arms and other supplies from the ship before it breaks apart and he builds a fenced-in habitat near a cave which he excavates. By making marks in a cross, he creates a calendar. By using tools salvaged from the ship, and some he makes himself from ironwood, he hunts, grows barley and rice, dries grapes to make raisins, learns to make pottery and he adopts a small parrot. He reads the Bible and becomes religious, thanking God for his fate in which nothing is missing, more years pass and Crusoe discovers native cannibals, who occasionally visit the island to kill and eat prisoners. At first he plans to them for committing an abomination but realizes he has no right to do so. He dreams of obtaining one or two servants by freeing prisoners, when a prisoner escapes, Crusoe helps him, naming his new companion Friday after the day of the week he appeared. Crusoe teaches him English and converts him to Christianity, after more natives arrive to partake in a cannibal feast and Friday kill most of the natives and save two prisoners.
One is Fridays father and the other is a Spaniard, who informs Crusoe about other Spaniards shipwrecked on the mainland. A plan is devised wherein the Spaniard would return to the mainland with Fridays father and bring back the others, build a ship, before the Spaniards return, an English ship appears, mutineers have commandeered the vessel and intend to maroon their captain on the island
Daniel Defoe, born Daniel Foe, was an English trader, journalist and spy, most famous for his novel Robinson Crusoe. He was a pioneer of economic journalism, Daniel Foe was probably born in Fore Street in the parish of St. Giles Cripplegate, London. Defoe added the aristocratic-sounding De to his name, and on occasion claimed descent from the family of De Beau Faux and his birthdate and birthplace are uncertain, and sources offer dates from 1659–1662, with 1660 considered the most likely. His father James Foe was a tallow chandler and a member of the Worshipful Company of Butchers. In 1667, when he was probably about seven, a Dutch fleet sailed up the Medway via the River Thames and his mother Annie had died by the time he was about ten. Defoe was educated at the Rev. James Fishers boarding school in Pixham Lane in Dorking, during this period, the English government persecuted those who chose to worship outside the Church of England. Defoe entered the world of business as a merchant, dealing at different times in hosiery, general woollen goods.
His ambitions were great and he was able to buy a country estate, in 1684, Defoe married Mary Tuffley, the daughter of a London merchant, receiving a dowry of £3,700 – a huge amount by the standards of the day. With his debts and political difficulties, the marriage may have been troubled, in 1685, Defoe joined the ill-fated Monmouth Rebellion but gained a pardon, by which he escaped the Bloody Assizes of Judge George Jeffreys. Queen Mary and her husband William III were jointly crowned in 1688, and Defoe became one of Williams close allies, some of the new policies led to conflict with France, thus damaging prosperous trade relationships for Defoe, who had established himself as a merchant. In 1692, Defoe was arrested for debts of £700, though his total debts may have amounted to £17,000 and his laments were loud and he always defended unfortunate debtors, but there is evidence that his financial dealings were not always honest. Following his release, he travelled in Europe and Scotland, and it may have been at this time that he traded wine to Cadiz, Porto.
By 1695, he was back in England, now using the name Defoe and serving as a commissioner of the glass duty. In 1696, he ran a tile and brick factory in what is now Tilbury in Essex, Defoes first notable publication was An Essay upon Projects, a series of proposals for social and economic improvement, published in 1697. From 1697 to 1698, he defended the right of King William III to an army during disarmament. His most successful poem, The True-Born Englishman, defended the king against the perceived xenophobia of his enemies, satirising the English claim to racial purity. In 1701, Defoe presented the Legions Memorial to the Speaker of the House of Commons, his employer Robert Harley and it demanded the release of the Kentish petitioners, who had asked Parliament to support the king in an imminent war against France. The death of William III in 1702 once again created a political upheaval, in it, he ruthlessly satirised both the High church Tories and those Dissenters who hypocritically practised so-called occasional conformity, such as his Stoke Newington neighbour Sir Thomas Abney
William Bourne (mathematician)
William Bourne was an English mathematician and former Royal Navy gunner who presented the first design for a navigable submarine and wrote important navigational manuals. He is often called William Bourne of Gravesend, in 1574, he produced a popular version of the Martín Cortés de Albacars Arte de Navegar, entitled A Regiment for the Sea. Bourne was critical of aspects of the original and produced a manual of more practical use to the seaman. He described how to make observations of the sun and stars, using a cross-staff, before publishing his submarine design, William Bourne was a jurat in Gravesend, England. His name first appears in the first charter of incorporation of Gravesend from June 5,1562 and his name appears once again as a jurat in the second charter of Gravesend, June 5,1568. During the time of the charter, the only records of regulations for trading in Gravesend are written in Bournes handwriting. This would imply that he held an office such as clerk of the market and he worked as an innkeeper during this time, one of fourteen in the town of Gravesend.
His design, detailed in his book Inventions or Devises published in 1578, was one of the first recorded plans for an underwater navigation vehicle and he designed an enclosed craft capable of submerging by decreasing the overall volume, and being rowed underwater. Bourne described a ship with a frame covered in waterproofed leather. The submarine was the subject of a modern-day recreation on season 3 of The Re-Inventors TV show, the recreation had limited functionality before it sank when water pressure ruptured some membranes on a test descent. Inventions or Devises, published in 1578, is one of William Bournes more important works and this book gives many guides and instructional tools for sailors, mostly concerning interactions with other ships. The 21st device listed is the earliest known description of a ships log, the 110th entry is a very early description of a telescope. He describes a device consisting of two glasses that, when arranged properly, will allow you to read a letter from an away or see a man, town.
This description predates the earliest known working telescope by 30 years, Bournes bibliography, Museum of the History of Science, University of Oxford webpages
William Oughtred was an English mathematician and Anglican minister. Oughtred introduced the × symbol for multiplication as well as the abbreviations sin, Oughtred was born at Eton in Buckinghamshire, and educated there and at Kings College, Cambridge, of which he became fellow. Being admitted to holy orders, he left the University of Cambridge about 1603, for a living at Shalford, he was presented in 1610 to the rectory of Albury, near Guildford in Surrey, where he settled. He married Christsgift Caryll, of the Caryll family of Tangley Hall at Wonersh, of which Lady Elizabeth Aungier, wife of Simon Caryll 1607-1619, was matriarch, about 1628 he was appointed by the Earl of Arundel to instruct his son in mathematics. He corresponded with some of the most eminent scholars of his time, including William Alabaster, Sir Charles Cavendish and he kept up regular contacts with Gresham College, where he knew Henry Briggs and Gunter. He offered free tuition to pupils, who included Richard Delamain. Seth Ward resided with Oughtred for six months to learn mathematics, and the physician Charles Scarburgh stayed at Albury, John Wallis.
Another Albury pupil was Robert Wood, who helped him get the Clavis through the press, the invention of the slide rule involved Oughtred in a priority dispute with Delamain. They disagreed on pedagogy in mathematics, with Oughtred arguing that theory should precede practice and he remained rector until his death in 1660 at Albury, a month after the restoration of Charles II. Oughtred had an interest in alchemy and astrology, the testimony for his occult activities is quite slender, but there has been an accretion to his reputation based on his contemporaries. According to John Aubrey, he was not entirely sceptical about astrology, William Lilly, an eminent astrologer, claimed in his autobiography to have intervened on behalf of Oughtred to prevent his ejection by Parliament in 1646. In fact Oughtred was protected at this time by Bulstrode Whitelocke, Aubrey states that he was defended by Sir Richard Onslow. It was used by George Wharton in publishing The Cabal of the Twelve Houses astrological by Morinus in 1659 and he expressed millenarian views to John Evelyn, as recorded in Evelyns Diary, entry for 28 August 1655.
Oughtreds name is remembered in the Oughtred Society, a group formed in the United States in 1991 for collectors of slide rules and it produces the twice-yearly Journal of the Oughtred Society and holds meetings and auctions for its members. He published, among other works, Clavis Mathematicae, in 1631. It became a classic, reprinted in editions, and used by Wallis. It was not ambitious in scope, but an epitome aiming to represent current knowledge of algebra concisely, the book became popular around 15 years later, as mathematics took a greater role in higher education. Wallis wrote the introduction to his 1652 edition, and used it to publicise his skill as cryptographer, in another, Oughtred promoted the talents of Wren
Technology is the collection of techniques, skills and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques and the like, the human species use of technology began with the conversion of natural resources into simple tools. The steady progress of technology has brought weapons of ever-increasing destructive power. It has helped develop more advanced economies and has allowed the rise of a leisure class, many technological processes produce unwanted by-products known as pollution and deplete natural resources to the detriment of Earths environment. Various implementations of technology influence the values of a society and raise new questions of the ethics of technology, examples include the rise of the notion of efficiency in terms of human productivity, and the challenges of bioethics. Philosophical debates have arisen over the use of technology, with disagreements over whether technology improves the condition or worsens it.
The use of the technology has changed significantly over the last 200 years. Before the 20th century, the term was uncommon in English, the term was often connected to technical education, as in the Massachusetts Institute of Technology. The term technology rose to prominence in the 20th century in connection with the Second Industrial Revolution, the terms meanings changed in the early 20th century when American social scientists, beginning with Thorstein Veblen, translated ideas from the German concept of Technik into technology. In German and other European languages, a distinction exists between technik and technologie that is absent in English, which translates both terms as technology. By the 1930s, technology referred not only to the study of the industrial arts and scholars have offered a variety of definitions. Ursula Franklin, in her 1989 Real World of Technology lecture, gave another definition of the concept, it is practice, the way we do things around here. The term is used to imply a specific field of technology, or to refer to high technology or just consumer electronics.
Bernard Stiegler, in Technics and Time,1, defines technology in two ways, as the pursuit of life by other than life, and as organized inorganic matter. Technology can be most broadly defined as the entities, both material and immaterial, created by the application of mental and physical effort in order to some value. In this usage, technology refers to tools and machines that may be used to solve real-world problems and it is a far-reaching term that may include simple tools, such as a crowbar or wooden spoon, or more complex machines, such as a space station or particle accelerator. Tools and machines need not be material, virtual technology, such as software and business methods. W. Brian Arthur defines technology in a broad way as a means to fulfill a human purpose
Cartography is the study and practice of making maps. Combining science and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively, the fundamental problems of traditional cartography are to, Set the maps agenda and select traits of the object to be mapped. This is the concern of map editing, traits may be physical, such as roads or land masses, or may be abstract, such as toponyms or political boundaries. Represent the terrain of the object on flat media. This is the concern of map projections, eliminate characteristics of the mapped object that are not relevant to the maps purpose. This is the concern of generalization, reduce the complexity of the characteristics that will be mapped. This is the concern of generalization, orchestrate the elements of the map to best convey its message to its audience. This is the concern of map design, modern cartography constitutes many theoretical and practical foundations of geographic information systems.
The earliest known map is a matter of debate, both because the term map isnt well-defined and because some artifacts that might be maps might actually be something else. A wall painting that might depict the ancient Anatolian city of Çatalhöyük has been dated to the late 7th millennium BCE, the oldest surviving world maps are from 9th century BCE Babylonia. One shows Babylon on the Euphrates, surrounded by Assyria and several cities, all, in turn, another depicts Babylon as being north of the world center. The ancient Greeks and Romans created maps since Anaximander in the 6th century BCE, in the 2nd century AD, Ptolemy wrote his treatise on cartography, Geographia. This contained Ptolemys world map – the world known to Western society. As early as the 8th century, Arab scholars were translating the works of the Greek geographers into Arabic, in ancient China, geographical literature dates to the 5th century BCE. The oldest extant Chinese maps come from the State of Qin, dated back to the 4th century BCE, in the book of the Xin Yi Xiang Fa Yao, published in 1092 by the Chinese scientist Su Song, a star map on the equidistant cylindrical projection.
Early forms of cartography of India included depictions of the pole star and these charts may have been used for navigation. Mappa mundi are the Medieval European maps of the world, approximately 1,100 mappae mundi are known to have survived from the Middle Ages. Of these, some 900 are found illustrating manuscripts and the remainder exist as stand-alone documents, the Arab geographer Muhammad al-Idrisi produced his medieval atlas Tabula Rogeriana in 1154
Robert Dudley (explorer)
Sir Robert Dudley was an English explorer and cartographer. In 1594, he led an expedition to the West Indies, the illegitimate son of Robert Dudley, 1st Earl of Leicester, he inherited the bulk of the Earls estate in accordance with his fathers will, including Kenilworth Castle. In 1603–1605, he tried unsuccessfully to establish his legitimacy in court, after that he left England forever, finding a new existence in the service of the Grand Dukes of Tuscany. There, he worked as an engineer and shipbuilder, and designed and published DellArcano del Mare and he was a skilled navigator and mathematician. In Italy, he styled himself Earl of Warwick and Leicester, as well as Duke of Northumberland, Robert Dudley was the son of Robert Dudley, 1st Earl of Leicester and his lover Douglas Sheffield, daughter of William Howard, 1st Baron Howard of Effingham. He grew up in the houses of his father and his fathers friends and his mother married Sir Edward Stafford in November 1579, and left for Paris. Leicester was fond of his son and often made trips to see him, Dudley was given an excellent education and was enrolled at Christ Church, Oxford, in 1587, with the status of filius comitis.
There, his mentor was Thomas Chaloner, who became his close friend. His will gave Dudley a large inheritance, including the castle and estate at Kenilworth, and on the death of his uncle, Ambrose Dudley, 3rd Earl of Warwick, the lordships of Denbigh and Chirk. In early 1591, Dudley was contracted to marry Frances Vavasour with the consent of Queen Elizabeth I, that year, Vavasour secretly married another man and was banished from court. In turn, the 17-year-old Dudley married Margaret, a sister of Sir Thomas Cavendishs, Dudley was excluded from court for this secret marriage, but only for a few days. Margaret was given two ships by her father Robert, named the Leicester and the Roebuck, in 1594, Dudley assembled a fleet of ships, including his flagship, the galleon Beare, as well as the Beares Whelpe, and the pinnaces Earwig and Frisking. He intended to use them to harass the Spaniards in the Atlantic, the Queen did not approve of his plans, because of his inexperience and the value of the ships.
She did commission him as a general but insisted that he sail to Guiana, Dudley recruited 275 veteran sailors, including the navigator Abraham Kendal, and the captains Thomas Jobson and Benjamin Wood. Dudleys fleet sailed on 6 November 1594, but a storm separated the ships. Dudley sent word to the captain of the Beares Whelp to join him in the Canary Islands or Cabo Blanco, at first, Dudleys trip proved unlucky, the Earwig sank, and most of the vessels he encountered were friendly. Dudley led only one raid in the Gulf of Lagos, in December, the expedition finally managed to capture two Spanish ships at Tenerife. Dudley renamed them Intent and Regard, manned them with his sailors and he sailed to Cabo Blanco, expecting to meet the Beares Whelpe there, but it did not show up