HISTORY WITH STEAM ENGINE

This article is about the history of the reciprocating-type steam engine

The first recorded rudimentary steam engine was the aeolipile described by Hero of Alexandria in the 1st century AD.Starting in the 12th century, a number of steam-powered devices were experimented with or proposed. In 1712 Thomas Newcomen's atmospheric engine became the first commercially successful engine using the principle of the piston and cylinder, which was the fundamental type steam engine used until the early 20th century.

During the industrial revolution, steam engines started to replace water and wind power, and eventually became the dominant source of power in the late 19th century and remaining so into the early decades of the 20th century, when the more efficient steam turbine and the internal combustion engine resulted in the rapid replacement of the steam engines. The steam turbine has become the most common method by which electrical power generators are driven.^[2] Investigations are being made into the practicalities of reviving the reciprocating steam engine as the basis for a new wave of advanced steam technology

Early uses of steam poweR

The earliest known rudimentary steam engine and reaction steam turbine, the aeolipile, is described by a Greek mathematician and engineer named Hero of Alexandria (Heron) in 1st century Roman Egypt, as recorded in his manuscript Spiritalia seu Pneumatica. Steam ejected tangentially from nozzles caused a pivoted ball to rotate. Its thermal efficiency was low. This suggests that the conversion of steam pressure into mechanical movement was known in Roman Egypt in the 1st century. Hero also devised a machine that used air heated in an altar fire to displace a quantity of water from a closed vessel. The weight of the water was made to pull a hidden rope to operate temple doors. Some historians have conflated the two inventions to assert, incorrectly, that the aeolipile was capable of useful work.^{[citation needed]}

According to William of Malmesbury, in 1125, Reims was home to a church that had an organ powered by air escaping from compression "by heated water", apparently designed and constructed by professor Gerbertus

Among the papers of Leonardo da Vinci dating to the late 15th century is the design for a steam-powered cannon called the Architonnerre which works by the sudden influx of hot water into a sealed red hot cannon

A rudimentary impact steam turbine was described in 1551 by Taqi al-Din, a philosopher, astronomer and engineer in 16th century Ottoman Egypt, who described a method for rotating a spit by means of a jet of steam playing on rotary vanes around the periphery of a wheel. A similar device for rotating a spit was also later described by John Wilkins in 1648. These devices were then called "mills" but are now known as steam jacks. Another similar rudimentary steam turbine is shown by Giovanni Branca, an Italian engineer, in 1629 for turning a cylindrical escapement device that alternately lifted and let fall a pair of pestles working in mortars The steam flow of these early steam turbines, however, was not concentrated and most of its energy was dissipated in all directions. This would have led to a great waste of energy and so they were never seriously considered for industrial use.

In 1605 French mathematician Florence Rivault in his treatise on artillery wrote on his discovery that water, if confined in a bombshell and heated, would explode the shells.

In 1606, the Spaniard, Jerónimo de Ayanz y Beaumont demonstrated and was granted a patent for a steam powered water pump. The pump was successfully used to drain the inundated mines of Guadalcanal, Spain.

In 1663 Edward Somerset, 2nd Marquess of Worcester published designs for raising water between floors employing a similar principle to that of a coffee percolator. His system was the first to separate the boiler from the pumping action. Water was admitted into a reinforced barrel from a cistern, and then a valve was opened to admit steam from a separate boiler. The pressure built over the top of the water, driving it up a pipe.He installed his steam-powered device on the wall of the Great Tower at Raglan Castle to supply water through the tower. The grooves in the wall where the engine was installed were still to be seen in the 19th century. However, no one was prepared to risk money for such a revolutionary concept, and without backers the machine remained undeveloped

  

As the 18th century advanced, the call was for higher pressures; this was strongly resisted by Watt who used the monopoly his patent gave him to prevent others from building high-pressure engines and using them in vehicles. He mistrusted the materials' resistance and the boiler technology of the day.

The important advantages of high pressure engines were:

1. They could be made much smaller than previously for a given power output. There was thus the potential for steam engines to be developed that were small and powerful enough to propel themselves and other objects. As a result, steam power for transportation now became a practicality in the form of ships and land vehicles, which revolutionised cargo businesses, travel, military strategy, and essentially every aspect of society.
2. Because of their smaller size, they were much less expensive.
3. They did not require the significant quantities of condenser cooling water needed by atmospheric engines.
4. They could be designed to run at higher speeds, making them more suitable for powering machinery.

The disadvantages were:

1. In the low pressure range they were less efficient than condensing engines, especially if steam was not used expansively.
2. They were more susceptible to boiler explosions

 

 

 

BOAT

History

Dugouts are the oldest type of boats found by archaeologists, and boats have served as transportation since the earliest times.Circumstantial evidence, such as the early settlement of Australia over 40,000 years ago, findings in Crete dated 130,000 years ago, and findings in Flores dated to 900,000 years ago,suggest that boats have been used since prehistoric times. The earliest boats are thought to have been logboats, and the oldest boats found by archaeological excavation date from around 7,000–10,000 years ago. The oldest recovered boat in the world is the Pesse canoe, a dugout made from the hollowed tree trunk of a Pinus sylvestris and constructed somewhere between 8200 and 7600 BC. This canoe is exhibited in the Drents Museum in Assen, Netherlands.Other very old dugout boats have also been recovered. Rafts have operated for at least 8,000 years. A 7,000-year-old seagoing reed boat has been found in Kuwait.Boats were used between 4000 and 3000 BC in Sumer, ancient Egypt and in the Indian Ocean.

Boats played an important role in the commerce between the Indus Valley Civilization and Mesopotamia. Evidence of varying models of boats has also been discovered at various Indus Valley archaeological sites. Uru craft originate in Beypore, a village in south Calicut, Kerala, in southwestern India. This type of mammoth wooden ship was constructed^[when?] using teak, without any iron, and had a transport capacity of 400 tonnes. The ancient Arabs and Greeks used such boats as trading vessels.^{[citation needed]}

The historians Herodotus, Pliny the Elder and Strabo record the use of boats for commerce, travel, and military purposes

 

Boats can be categorized into three main types:

• Unpowered or human-powered boats. Unpowered boats include rafts and floats meant for one-way downstream travel. Human-powered boats include canoes, kayaks, gondolas and boats propelled by poles like a punt.
• Sailboats, which are propelled solely by means of sails.
• Motorboats, which are propelled by mechanical means, such as engines.
  • Ski boats are specialized motorboats specifically designed to safely tow one or more water skiers. This is achieved by using a high-horsepower, marine automobile engine, usually positioned in the midsection and powered through a direct drive to the propeller. A skier is pulled on a towrope attached to a tow bar located in front of the drive motor and affixed to the bottom of the hull. Each approved towboat must meet or exceed a preset set of standards defined by the USA Water Ski Federation, formerly the American Water Ski Association, AWSA.^{[citation needed )}
  •  
  A Ukrainian dugout (dowbanka) dating from the end of the 19th century. Radomysl Castle, Ukraine

Several key components make up the main structure of most boats. The hull is the main structural component of the boat and provides buoyancy. The gunnel, which make up the sides of the boat, offers protection from water and makes the boat harder to sink. The roughly horizontal, chambered structures spanning the hull of the boat are referred to as the deck. A ship often has several decks, but a boat is unlikely to have more than one, if any. Above the deck are the superstructures. The underside of a deck is the deck head.

An enclosed space on a boat is referred to as a cabin. Several structures make up a cabin, including a coach-roof, which is a lightweight structure which spans a raised cabin. The "floor" of a cabin is properly known as the sole, but is more likely to be called the floor (a floor is properly, a structural member which ties a frame to the keelson and keel). The vertical surfaces dividing the internal space are bulkheads.

The keel is a lengthwise structural member to which the frames are fixed (sometimes referred to as a "backbone").

The front (or fore end) of a boat is called the bow. Boats of earlier times often featured a figurehead protruding from the bow. The rear (or aft end) of the boat is called the stern. The right side (facing forward) is starboard and the left side is port.

Nearly every boat is given a name by the owner, and this is how the boat is referred to in the boating community, and in some cases, in legal or title paperwork. Boat names vary from whimsical to humorous to seriousUntil the mid-19th century most boats were made of natural materials, primarily wood, although reed, bark and animal skins were also used. Early boats include the bound-reed style of boat seen in Ancient Egypt, the birch bark canoe, the animal hide-covered kayak and coracle and the dugout canoe made from a single log.

Traditional Toba Batak boat (circa 1870), photograph by Kristen Feilberg

Bill Streever describes a boat made by the native Inupiat people in Barrow, Alaska as "a skin boat, an umiaq, built from the stitched hides of bearded seals and used to hunt bowhead whales in the open-water leads during spring..."

By the mid-19th century, many boats had been built with iron or steel frames but still planked in wood. In 1855 ferro-cement boat construction was patented by the French, who coined the name "ferciment". This is a system by which a steel or iron wire framework is built in the shape of a boat's hull and covered (trowelled) over with cement. Reinforced with bulkheads and other internal structure, it is strong but heavy, easily repaired, and, if sealed properly, will not leak or corrode. These materials and methods were copied all over the world and have faded in and out of popularity to the present time. As the forests of Britain and Europe continued to be over-harvested to supply the keels of larger wooden boats, and the Bessemer process (patented in 1855) cheapened the cost of steel, steel ships and boats began to be more common. By the 1930s boats built entirely of steel from frames to plating were seen replacing wooden boats in many industrial uses, also for fishing fleets. Private recreational boats of steel are however uncommon. In the mid-20th century aluminium gained popularity. Though much more expensive than steel, there are now aluminium alloys available that do not corrode in salt water, and an aluminium boat built to similar load carrying standards is lighter in weight than the steel equivalent . Around the mid-1960s, boats made of glass-reinforced plastic, more commonly known as fibreglass, became popular, especially for recreational boats. The United States Coast Guard refers to such boats as 'FRP' (for fibre-reinforced plastic) boats.

Fibreglass boats are strong, and do not rust (iron oxide), corrode, or rot. They are, however susceptible to structural degradation from sunlight and extremes in temperature over their lifespan. Fibreglass provides structural strength, especially when long woven strands are laid, sometimes from bow to stern, and then soaked in epoxy or polyester resin to form the hull. Whether hand laid or built in a mould, Fibre-reinforced plastic (FRP) boats usually have an outer coating of gelcoat, which is a thin solid colored layer of polyester resin that adds no structural strength, but does create a smooth surface which can be buffed to a high shine and also acts as a protective layer against sunlight. FRP structures can be made stiffer with sandwich panels, where the FRP encloses a lightweight core such as balsa or foam. Cored FRP is most often found in decking, which helps keep down weight that will be carried above the waterline. The addition of wood makes the cored structure of the boat susceptible to rotting, which puts a greater emphasis on not allowing damaged sandwich structures to go unrepaired. Plastic based foam cores are less vulnerable. The phrase 'advanced composites' in FRP construction may indicate the addition of carbon fibre, Kevlar or other similar materials, but it may also indicate methods designed to introduce less expensive and, by at least one yacht surveyor's eyewitness accounts,^[20] less structurally sound materials.

Cold moulding is similar to FRP in as much as it involves the use of epoxy or polyester resins, but the structural component is wood instead of fibreglass. In cold moulding very thin strips of wood are layered over a form or mould. Each layer is coated with resin and another directionally alternating layer is laid on top. In some processes the subsequent layers are stapled or otherwise mechanically fastened to the previous layers, but in other processes the layers are weighted or even vacuum bagged to hold them together while the resin sets. Layers are built up until the required hull thickness is achieved.

Boats or watercraft have also been made of materials such as foam or plastic, but most homebuilts today are built of plywood and either painted or covered with a layer of fibreglass and resin.

TECHNICE

This article is about the use and knowledge of techniques and processes for producing goods and services

  ("science of craft", from Greek τέχνη, techne, "art, skill, cunning of hand"; and -λογία, -logia) is the collection of techniques, skills, methods 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, processes, etc. or it can be embedded in machines, computers, devices and factories, which can be operated by individuals without detailed knowledge of the workings of such things.

The human species' use of technology began with the conversion of natural resources into simple tools. The prehistoric discovery of how to control fire and the later Neolithic Revolution increased the available sources of food and the invention of the wheel helped humans to travel in and control their environment. Developments in historic times, including the printing press, the telephone, and the Internet, have lessened physical barriers to communication and allowed humans to interact freely on a global scale. The steady progress of military technology has brought weapons of ever-increasing destructive power, from clubs to nuclear weapons.

Technology has many effects. It has helped develop more advanced economies (including today's global economy) 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 Earth's environment. Various implementations of technology influence the values of a society and new technology often raises new ethical questions. Examples include the rise of the notion of efficiency in terms of human productivity, a term originally applied only to machines, and the challenge of traditional norms.

Philosophical debates have arisen over the use of technology, with disagreements over whether technology improves the human condition or worsens it. Neo-Luddism, anarcho-primitivism, and similar reactionary movements criticise the pervasiveness of technology in the modern world, opining that it harms the environment and alienates people; proponents of ideologies such as transhumanism and techno-progressivism view continued technological progress as beneficial to society and the human condition

Technology is the collection of tools, including machinery, modifications, arrangements and procedures used by humans

History

The history of technology is the history of the invention of tools and techniques and is similar to other sides of the history of humanity. Technology can refer to methods ranging from as simple as language and stone tools to the complex genetic engineering and information technology that has emerged since the 1980s.

New knowledge has enabled people to create new things, and conversely, many scientific endeavors are made possible by technologies which assist humans in travelling to places they could not previously reach, and by scientific instruments by which we study nature in more detail than our natural senses allow.

Since much of technology is applied science, technical history is connected to the history of science. Since technology uses resources, technical history is tightly connected to economic history. From those resources, technology produces other resources, including technological artifacts used in everyday life.

Technological change affects, and is affected by, a society's cultural traditions. It is a force for economic growth and a means to develop and project economic, political and military power.

 

1900s photograph of barge pullers on the Volga River. Pushing was done with poles and manual pulling using overhanging tree branches. Horses were also used.

Science, engineering and technology

 

The distinction between science, engineering and technology is not always clear. Science is the reasoned investigation or study of natural phenomena, aimed at discovering enduring principles among elements of the phenomenal world by employing formal techniques such as the scientific method. Technologies are not usually exclusively products of science, because they have to satisfy requirements such as utility, usability and safety.

 Engineering is the goal-oriented process of designing and making tools and systems to exploit natural phenomena for practical human means, often (but not always) using results and techniques from science. The development of technology may draw upon many fields of knowledge, including scientific, engineering, mathematical, linguistic, and historical knowledge, to achieve some practical result

Technology is often a consequence of science and engineering — although technology as a human activity precedes the two fields. For example, science might study the flow of electrons in electrical conductors, by using already-existing tools and knowledge. This new-found knowledge may then be used by engineers to create new tools and machines, such as semiconductors, computers, and other forms of advanced technology. In this sense, scientists and engineers may both be considered technologists; the three fields are often considered as one for the purposes of research and reference

The exact relations between science and technology in particular have been debated by scientists, historians, and policymakers in the late 20th century, in part because the debate can inform the funding of basic and applied science. In the immediate wake of World War II, for example, in the United States it was widely considered that technology was simply "applied science" and that to fund basic science was to reap technological results in due time. An articulation of this philosophy could be found explicitly in Vannevar Bush's treatise on postwar science policy, Science—The Endless Frontier: "New products, new industries, and more jobs require continuous additions to knowledge of the laws of nature ... This essential new knowledge can be obtained only through basic scientific research." In the late-1960s, however, this view came under direct attack, leading towards initiatives to fund science for specific tasks (initiatives resisted by the scientific community). The issue remains contentious—though most analysts resist the model that technology simply is a result of scientific research

 

Bicycle

A bicycle, often called a bike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A bicycle rider is called a cyclist, or bicyclist

Bicycles were introduced in the 19th century in Europe and as of 2003, more than 1 billion have been produced worldwide, twice as many as the number of automobiles that have been produced.They are the principal means of transportation in many regions. They also provide a popular form of recreation, and have been adapted for use as children's toys, general fitness, military and police applications, courier services, and bicycle racing.

The basic shape and configuration of a typical upright, or safety bicycle, has changed little since the first chain-driven model was developed around 1885. But many details have been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for many types of cycling

The bicycle's invention has had an enormous effect on society, both in terms of culture and of advancing modern industrial methods. Several components that eventually played a key role in the development of the automobile were initially invented for use in the bicycle, including ball bearings, pneumatic tires, chain-driven sprockets, and tension-spoked wheels.

The Dandy horse, also called Draisienne or Laufmaschine, was the first human means of transport to use only two wheels in tandem and was invented by the German Baron Karl von Drais. It is regarded as the modern bicycle's forerunner; Drais introduced it to the public inMannheim in summer 1817 and in Paris in 1818.^] Its rider sat astride a wooden frame supported by two in-line wheels and pushed the vehicle along with his/her feet while steering the front whe

The first mechanically-propelled, two-wheeled vehicle may have been built by Kirkpatrick MacMillan, a Scottish blacksmith, in 1839, although the claim is often disputed. He is also associated with the first recorded instance of a cycling traffic offense, when a Glasgow newspaper in 1842 reported an accident in which an anonymous "gentleman from Dumfries-shire... bestride a velocipede... of ingenious design" knocked over a little girl in Glasgow and was fined five shillings

Michaux's son on a velocipede 1868

In the early 1860s, Frenchmen Pierre Michaux and Pierre Lallement took bicycle design in a new direction by adding a mechanical crank drive with pedals on an enlarged front wheel (thevelocipede). Another French inventor named Douglas Grasso had a failed prototype of Pierre Lallement's bicycle several years earlier. Several inventions followed using rear-wheel drive, the best known being the rod-driven velocipede by Scotsman Thomas McCall in 1869. In that same year, bicycle wheels with wire spokes were patented by Eugène Meyer of Paris.The French vélocipède, made of iron and wood, developed into the "penny-farthing" (historically known as an "ordinary bicycle", a retronym, since there was then no other kind).^] It featured a tubular steel frame on which were mounted wire-spoked wheels with solid rubber tires. These bicycles were difficult to ride due to their high seat and poor weight distribution. In 1868 Rowley Turner, a sales agent of the Coventry Sewing Machine Company (which soon became the Coventry Machinists Company), brought a Michaux cycle to Coventry, England. His uncle, Josiah Turner, and business partner James Starley, used this as a basis for the 'Coventry Model' in what became Britain's first cycle factory.

The dwarf ordinary addressed some of these faults by reducing the front wheel diameter and setting the seat further back. This, in turn, required gearing—effected in a variety of ways—to efficiently use pedal power. Having to both pedal and steer via the front wheel remained a problem. J. K. Starley (nephew of James Starley), J. H. Lawson, and Shergold solved this problem by introducing the chain drive (originated by the unsuccessful "bicyclette" of Englishman Henry Lawson), connecting the frame-mounted cranks to the rear wheel. These models were known as safety bicycles, dwarf safeties, or upright bicycles for their lower seat height and better weight distribution, although without pneumatic tires the ride of the smaller-wheeled bicycle would be much rougher than that of the larger-wheeled variety. Starley's 1885 Rover, manufactured in Coventry^] is usually described as the first recognizably modern bicycle. Soon the seat tube was added, creating the modern bike's double-triangle diamond frame.

Further innovations increased comfort and ushered in a second bicycle craze, the 1890s Golden Age of Bicycles. In 1888, Scotsman John Boyd Dunlop introduced the first practical pneumatic tire, which soon became universal. Soon after, the rear freewheel was developed, enabling the rider to coast. This refinement led to the 1890s invention ofcoaster brakes. Dérailleur gears and hand-operated Bowden cable-pull brakes were also developed during these years, but were only slowly adopted by casual riders. By the turn of the century, cycling clubs flourished on both sides of the Atlantic, and touring and racing became widely popular.

Bicycles and horse buggies were the two mainstays of private transportation just prior to the automobile, and the grading of smooth roads in the late 19th century was stimulated by the widespread advertising, production, and use of these devices.

Wooden draisine (around 1820), the first two-wheeler and as such the archetype of the bicycle

HISTORY OF FLIGHT

Wright brothers

he Wright brothers, Orville (August 19, 1871 – January 30, 1948) and Wilbur (April 16, 1867 – May 30, 1912), were two American brothers, inventors, and aviation pioneers who are credited^]

 with inventing and building the world's first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903. From 1905 to 1907, the brothers developed their flying machine into the first practical fixed-wing aircraft. Although not the first to build and fly experimental aircraft, the Wright brothers were the first to invent aircraft controls that made fixed-wing powered flight possible

The brothers' fundamental breakthrough was their invention of three-axis control, which enabled the pilot to steer the aircraft effectively and to maintain its equilibrium.^] This method became and remains standard on fixed-wing aircraft of all kinds.^] From the beginnig of their aeronautical work, the Wright brothers focused on developing a reliable method of pilot control as the key to solving "the flying problem". This approach differed significantly from other experimenters of the time who put more emphasis on developing powerful engines. Using a small homebuilt wind tunnel, the Wrights also collected more accurate data than any before, enabling them to design and build wings and propellers that were more efficient than any before. Their first U.S. patent, 821,393, did not claim invention of a flying machine, but rather, the invention of a system of aerodynamic control that manipulated a flying machine's surfaces.

They gained the mechanical skills essential for their success by working for years in their shop with printing presses, bicycles, motors, and other machinery. Their work with bicycles in particular influenced their belief that an unstable vehicle like a flying machine could be controlled and balanced with practice. From 1900 until their first powered flights in late 1903, they conducted extensive glider tests that also developed their skills as pilots. Their bicycle shop employeeCharlie Taylor became an important part of the team, building their first airplane engine in close collaboration with the brothers

The Wright brothers' status as inventors of the airplane has been subject to counter-claims by various parties. Much controversy persists over the many competing claims of early aviators. Historian Edward Roach argues that they were excellent self-taught engineers with a knack for tinkering more than for systematic research, but they proved to be poor businessmen

Toward flight

In July 1899 Wilbur put wing warping to the test by building and flying a biplane kite with a five-foot (1.5m) wingspan. When the wings were warped, or twisted, one end of the wings produced more lift and the other end less lift. The unequal lift made the wings tilt, or bank: the end with more lift rose, while the other end dropped, causing a turn in the direction of the lower end. The warping was controlled by four cords attached to the kite, which led to two sticks held by the kite flyer, who tilted them in opposite directions to twist the wings

n 1900 the brothers went to Kitty Hawk, North Carolina to begin their manned gliding experiments. In his reply to Wilbur's first letter, Octave Chanute had suggested the mid-Atlantic coast for its regular breezes and soft sandy landing surface. Wilbur also requested and examined U.S. Weather Bureau data, and decided on Kitty Hawk after receiving information from the government meteorologist stationed there.^[38] Kitty Hawk, although remote, was closer to Dayton than other places Chanute had suggested, including California and Florida. The spot also gave them privacy from reporters, who had turned the 1896 Chanute experiments at Lake Michigan into something of a circus. Chanute visited them in camp each season from 1901 to 1903 and saw gliding experiments, but not the powered flights

Gliders

The Wrights based the design of their kite and full-size gliders on work done in the 1890s by other aviation pioneers. They adopted the basic design of the Chanute-Herring biplane hang glider ("double-decker" as the Wrights called it), which flew well in the 1896 experiments near Chicago, and used aeronautical data on lift that Lilienthal had published. The Wrights designed the wings with camber, a curvature of the top surface. The brothers did not discover this principle, but took advantage of it. The better lift of a cambered surface compared to a flat one was first discussed scientifically by Sir George Cayley. Lilienthal, whose work the Wrights carefully studied, used cambered wings in his gliders, proving in flight the advantage over flat surfaces. The wooden uprights between the wings of the Wright glider were braced by wires in their own version of Chanute's modified Pratt truss, a bridge-building design he used for his biplane glider (initially built as a triplane). The Wrights mounted the horizontal elevator in front of the wings rather than behind, apparently believing this feature would help to avoid, or protect them, from a nosedive and crash like the one that killed Lilienthal.^] Wilbur incorrectly believed a tail was not necessary,^] and their first two gliders did not have one. According to some Wright biographers, Wilbur probably did all the gliding until 1902, perhaps to exercise his authority as older brother and to protect Orville from harm as he did not want to have to explain to Bishop Wright if Orville got injured

Glider Vital Statistics

	Wingspan	Wing area	Chord	Camber	Aspect ratio	Length	Weight
1900	17 ft 6 in (5.33 m)	165 sq ft (15 m2)	5 ft (2 m)	1/20	3.5:1	11 ft 6 in (3.51 m)	52 lb (24 kg)
1901	22 ft (7 m)	290 sq ft (27 m2)	7 ft (2.1 m)	1/12,*1/19	3:1	14 ft (4.3 m)	98 lb (44 kg)
1902	32 ft 1 in (9.78 m)	305 sq ft (28 m2)	5 ft (1.5 m)	1/20–1/24	6.5:1	17 ft (5.2 m)	112 lb (51 kg)

* (This airfoil caused severe stability problems; the Wrights modified the camber on-site.)

1900 Glider

The brothers flew the glider for only a few days in the early autumn of 1900 at Kitty Hawk. In the first tests, probably on October 3, Wilbur was aboard while the glider flew as a kite not far above the ground with men below holding tether ropes.^] Most of the kite tests were unpiloted, with sandbags or chains (and even a local boy as ballas

They tested wing-warping using control ropes from the ground. The glider was also tested unmanned while suspended from a small homemade tower. Wilbur (but not Orville) made about a dozen free glides on only a single day, October 20. For those tests the brothers trekked four miles (6 km) south to the Kill Devil Hills, a group of sand dunes up to 100 feet (30 m) high (where they made camp in each of the next three years). Although the glider's lift was less than expected (causing most tests to be unmanned), the brothers were encouraged because the craft's front elevator worked well and they had no accidents. However, the small number of free glides meant they were not able to give wing-warping a true test

The pilot lay flat on the lower wing, as planned, to reduce aerodynamic drag. As a glide ended, the pilot was supposed to lower himself to a vertical position through an opening in the wing and land on his feet with his arms wrapped over the framework. Within a few glides, however, they discovered the pilot could remain prone on the wing, headfirst, without undue danger when landing. They made all their flights in that position for the next five years

Wilbur (left) and Orville (right) as children in 1876

HISTORY OF ELECTROMAGNETIC THEORY

The history of electromagnetic theory begins with ancient measures to deal with atmospheric electricity, in particular lightning.^[1]People then had little understanding of electricity, and were unable to scientifically explain the phenomena^] In the 19th century there was a unification of the history of electric theory with the history of magnetic theory. It became clear that electricity should be treated jointly with magnetism, because wherever charges are in motion electric current results and, magnetism is due to electric current. The source term for electric field is electric charge where as that for magnetic field is electric current( charges in motion). Magnetism was not fully explained until the idea of magnetic induction was developed. Electricity was not fully explained until the idea of electric charge was developed.

Ancient and classical history

The knowledge of static electricity dates back to the earliest civilizations, but for millennia it remained merely an interesting and mystifying phenomenon, without a theory to explain its behavior and often confused with magnetism. The ancients were acquainted with rather curious properties possessed by two minerals, amber (Greek: ἤλεκτρον,electron) and magnetic iron ore (Greek: Μάγνης λίθος, Magnes lithos, "the Magnesian stone, lodestone"). Amber, when rubbed, attracts light bodies; magnetic iron ore has the power of attracting iron

Based on his find of an Olmec hematite artifact in Central America, the American astronomer John Carlson has suggested that "the Olmec may have discovered and used the geomagnetic lodestone compass earlier than 1000 BC". If true, this "predates the Chinese discovery of the geomagnetic lodestone compass by more than a millennium".^] Carlson speculates that the Olmecs may have used similar artifacts as a directional device for astrological or geomantic purposes, or to orient their temples, the dwellings of the living or the interments of the dead. The earliest Chinese literature reference to magnetism lies in a 4th-century BC book called Book of the Devil Valley Master (鬼谷子): "The lodestonemakes iron come or it attracts i

Long before any knowledge of electromagnetism existed, people were aware of the effects of electricity. Lightning and other manifestations of electricity such as St. Elmo's fire were known in ancient times, but it was not understood that these phenomena had a common origin. Ancient Egyptians were aware of shocks when interacting with electric fish (such as the electric catfish) or other animals (such as electric eels). The shocks from animals were apparent to observers since pre-history by a variety of peoples that came into contact with them. Texts from 2750 BC by the ancient Egyptians referred to these fish as "thunderer of the Nile" and saw them as the "protectors" of all the other fish.^] Another possible approach to the discovery of the identity of lightning and electricity from any other source, is to be attributed to the Arabs, who before the 15th century used the same Arabic word for lightning (barq) and the electric ray

Thales of Miletus, writing at around 600 BC, noted that rubbing fur on various substances such as amber would cause them to attract specks of dust and other light objects. Thales wrote on the effect now known as static electricity. The Greeks noted that if they rubbed the amber for long enough they could even get an electric spark to jump

The electrostatic phenomena was again reported millennia later by Roman and Arabic naturalists and physicians.Several ancient writers, such as Pliny the Elder and Scribonius Largus, attested to the numbing effect of electric shocks delivered by catfish and torpedo rays. Pliny in his books writes: "The ancient Tuscans by their learning hold that there are nine gods that send forth lightning and those of eleven sorts." This was in general the early pagan idea of lightning^] The ancients held some concept that shocks could travel along conducting objects.^]Patients suffering from ailments such as gout or headache were directed to touch electric fish in the hope that the powerful jolt might cure them

A number of objects found in Iraq in 1938 dated to the early centuries AD (Sassanid Mesopotamia), called the Baghdad Battery, resembles a galvanic cell and is believed by some to have been used for electroplating. The claims are controversial because of supporting evidence and theories for the uses of the artifacts, physical evidence on the objects conducive for electrical functions,^[18]and if they were electrical in nature. As a result the nature of these objects is based on speculation, and the function of these artifacts remains in doubt

Improving the electric machine

The electric machine was subsequently improved by Francis Hauksbee, Litzendorf, and by Prof. Georg Matthias Bose, about 1750. Litzendorf, researching for Christian August Hausen, substituted a glass ball for the sulphur ball of Guericke. Bose was the first to employ the "prime conductor" in such machines, this consisting of an iron rod held in the hand of a person whose body was insulated by standing on a block of resin.Ingenhousz, during 1746, invented electric machines made of plate glass.Experiments with the electric machine were largely aided by the discovery of the property of a glass plate, when coated on both sides with tinfoil, of accumulating a charge of electricity when connected with a source of electromotive force. The electric machine was soon further improved by Andrew Gordon, a Scotsman, Professor at Erfurt, who substituted a glass cylinder in place of a glass globe; and by Giessing of Leipzig who added a "rubber" consisting of a cushion of woollen material. The collector, consisting of a series of metal points, was added to the machine by Benjamin Wilson about 1746, and in 1762, John Canton of England (also the inventor of the first pith-ball electroscope) improved the efficiency of electric machines by sprinkling an amalgam of tin over the surface of the rubber.