Joseph-Michel Montgolfier and Jacques-Étienne Montgolfier were paper manufacturers from Annonay, in Ardèche, France best known as inventors of the Montgolfière-style hot air balloon, globe aérostatique. They launched the first piloted ascent. Joseph Michel invented the self-acting hydraulic ram, Jacques Étienne founded the first paper-making vocational school and the brothers invented a process to manufacture transparent paper; the Montgolfier brothers Joseph-Michel and Jacques-Étienne were born into a family of paper manufacturers founded in 1534 in Annonay, in Ardèche, France. Their parents were his wife, Anne Duret, who had 16 children. Pierre Montgolfier established Raymond, as his successor. Joseph-Michel was the 12th child and was described as a maverick and dreamer and was impractical in terms of business and personal affairs. Étienne was the 15th child, had a much more and businesslike temperament and was sent to Paris to train as an architect. After the sudden and unexpected death of Raymond in 1772, he was recalled to Annonay to run the family business.
In the subsequent 10 years, Étienne applied his talent for technical innovation to the family business of paper making, which as now was a high-tech industry. He succeeded in incorporating the latest Dutch innovations of the day into the family mills. Of the two brothers, it was Joseph, first interested in aeronautics, he first contemplated building machines when he observed laundry drying over a fire incidentally form pockets that billowed upwards. Joseph made his first definitive experiments in November 1782 while living in Avignon, he reported some years that he was watching a fire one evening while contemplating one of the great military issues of the day—an assault on the fortress of Gibraltar, which had proved impregnable from both sea and land. Joseph mused on the possibility of an air assault using troops lifted by the same force, lifting the embers from the fire, he believed that the smoke itself was the buoyant part and contained within it a special gas, which he called "Montgolfier Gas", with a special property he called levity, why he preferred smoldering fuel.
Joseph built a box-like chamber 1×1×1.3 m out of thin wood, covering the sides and top with lightweight taffeta cloth. He lit some paper under the bottom of the box; the contraption lifted off its stand and collided with the ceiling. Joseph recruited his brother to balloon building by writing, "Get in a supply of taffeta and of cordage and you will see one of the most astonishing sights in the world." The two brothers built a similar device, scaled up by three. On 14 December 1782 they did their first test flight, lighting with wool and hay, the lifting force was so great, that they lost control of their craft; the device floated nearly two kilometers and was destroyed after landing by the "indiscretion" of passersby. To make a public demonstration and to claim its invention the brothers constructed a globe-shaped balloon of sackcloth tightened with three thin layers of paper inside; the envelope weighed 225 kg. It was held together by 1,800 buttons. A reinforcing fish net of cord covered the outside of the envelope.
On 4 June 1783, they flew the balloon at Annonay in front of a group of dignitaries from the États ″particuliers″″. The flight covered 2 km, lasted 10 minutes, had an estimated altitude of 1,600-2,000 m. Word of their success reached Paris. Étienne went to the capital to make further demonstrations and to solidify the brothers' claim to the invention of flight. Joseph, given shyness, remained with the family. Étienne was the epitome of sober virtues... modest in clothes and manner... In collaboration with the wallpaper manufacturer Jean-Baptiste Réveillon, Étienne constructed a 37,500-cubic-foot envelope of taffeta coated with a varnish of alum for fireproofing; the balloon was sky blue and decorated with golden flourishes, signs of the zodiac, suns. The design showed the intervention of Réveillon; the next test was on 11 September from the grounds of la Folie Titon, close to Réveillon's house. There was some concern about the effects of flight into the upper atmosphere on living creatures; the king proposed to launch two convicted criminals, but it is most that the inventors decided to send a sheep, a duck, a rooster aloft first.
On 19 September 1783, the Aérostat Réveillon was flown with the first living beings in a basket attached to the balloon: a sheep called Montauciel, a duck and a rooster. The sheep was believed to have a reasonable approximation of human physiology; the duck was expected to be unharmed by being lifted and was included as a control for effects created by the aircraft rather than the altitude. The rooster was included as a further control; the demonstration was performed at the royal palace in Versailles, before King Louis XVI of France and Queen Marie Antoinette and a crowd. The flight lasted eight minutes, covered two miles, obtained an altitude of about 1,500 feet; the craft landed safely after flying. Since the animals survived, the king allowed flights with humans. Again in collaboration with Réveillon, Étienne built a 60,000-cubic-foot (1
Redruth is a town and civil parish in Cornwall, United Kingdom. The population of Redruth was 14,018 at the 2011 census. In the same year the population of the Camborne-Redruth urban area, which includes Carn Brea and several satellite villages, stood at 55,400 making it the largest conurbation in Cornwall. Redruth lies at the junction of the A393 and A3047 roads, on the route of the old London to Land's End trunk road, is 9 miles west of Truro, 12 miles east of St Ives, 18 miles north east of Penzance and 11 miles north west of Falmouth. Camborne and Redruth together form the largest urban area in Cornwall and before local government reorganisation were an urban district; the name Redruth derives from its older Cornish name, Rhyd-ruth. It means Red Ford; the first syllable'red' means ford. The second'ruth' means red. Rhyd is the older form of'Res', a Cornish equivalent to a ford, a common Celtic word, it is the - ruth. Traditionally in the Penwith Hundred, the town has developed away from the original settlement, near where the present Churchtown district of Redruth stands today.
This location is a steeply wooded valley, with Carn Brea on one side and the now-called Bullers Hill on the other. The presence of shallow lodes of tin and copper lying east to west made it an advantageous site for extracting metals, tin and copper; the first settlers stayed by a crossing in the river and started extracting metal ores, this process turned the colour of the river red. Redruth was a small market town overshadowed by its neighbours until a boom in the demand for copper ore during the 18th century. Copper ore had been discarded by the Cornish tin-mining industry but was now needed to make brass, an essential metal in the Industrial Revolution. Surrounded by copper ore deposits, Redruth became one of the largest and richest mining areas in Britain and the town's population grew markedly, although most miners' families remained poor. In the 1880s and 1890s the town end of Clinton Road gained a number of institutions, notably a School of Mines and Art School in 1882–83, St. Andrew's Church in 1883 and, the Free Library, built in 1895.
The Mining Exchange was built in 1880 as a place for the trading of mineral stock. By the turn of the 20th century, Victoria Park had been laid out to commemorate the Golden Jubilee and this part of town had taken on its present appearance – a far cry from the jumble of mining activity that had taken place there in the early 19th century. Redruth was making its transition from a market town dominated by mines and industry to a residential centre. By the end of the 19th century, the Cornish mining industry was in decline and Britain was importing most of its copper ore. To find employment, many miners emigrated to the newer mining industries in the Americas, Mexico and South Africa. Cornwall's last operational mine, South Crofty at Pool between Redruth and Camborne, closed in March 1998. See Camborne#Governance. Redruth School, a Technology College, is a secondary school and sixth form college, for ages 11–18; the town used to have a coeducational independent school, Highfields Private School, but this closed in 2012.
Primary schools within the town include Pennoweth School, Treleigh School, Treloweth Community Primary School, Trewirgie Infant School and Trewirgie Junior School. The Curnow Community Special School caters for students with special needs; the Parish Church of St Uny, some distance from the town centre, is of Norman foundation but was rebuilt in 1756. The patron saint is honoured at Lelant; the tower is two centuries earlier and the whole church is built of granite. A chapel of ease was built in the town in 1828 but it is no longer in use. Other places of worship include the Wesleyan Church of 1826, the Free Methodist Church of 1864 and the Quaker Meeting House of 1833; the former post office in Alma Place is now known as the Cornish Studies Centre: housed there is the collection of Tregellas Tapestries which depict the history of Cornwall in embroidery. The Mining Exchange building is now used as a housing advice centre; the house now called Murdoch House in the middle of Cross Street was erected in the 1660s as a chapel and it afterwards became a prison.
William Murdoch lived in it from 1782 to 1798. During this time, he worked on local tin and copper mines, erecting engines on behalf of Boulton and Watt, he fitted the house out with gas lighting from coal gas – this was the first house in the world with this type of lighting. In the 19th century, the house was used as a tea room, run by a Mrs Knuckey. In 1931 Mr A. Pearce Jenkin, a leading citizen of Redruth purchased the house and gave it as a gift to the Society of Friends. Murdoch House has since been restored and is now used by the Redruth Old Cornwall Society, as well as the Cornish-American Connection and the Redruth Story Group. Next door are St. Rumon's Gardens. A bronze sculpture of a Cornish miner by artist David Annand standing at 6 feet 7 inches was erected in April 2008; the sculpture was commissioned by the Redruth Public Realm Working Party's Minin
Cornelis Jacobszoon Drebbel was a Dutch engineer and inventor. He was the builder of the first navigable submarine in 1620 and an innovator who contributed to the development of measurement and control systems and chemistry. Cornelis Drebbel was born in Alkmaar, Holland in an Anabaptist family in 1572. After some years at the Latin school in Alkmaar, around 1587, he attended the Academy in Haarlem located in North-Holland. Teachers at the Academy were Hendrik Goltzius, painter and humanist, Karel van Mander, writer and Cornelis Corneliszoon of Haarlem. Drebbel became a skilled engraver on copperplate and took an interest in alchemy. In 1595 he married Sophia Jansdochter Goltzius, younger sister of Hendrick, settled at Alkmaar, they had at least six children. Drebbel worked as a painter and cartographer, but he was in constant need of money because of the prodigal lifestyle of his wife. In 1598 he obtained a sort of perpetual clockwork. In 1600, Drebbel was in Middelburg. In that spectacle making center he may have picked up knowledge in the art of lens grinding and would construct a magic lantern and a camera obscura.
Around 1604 the Drebbel family moved to England at the invitation of the new king, James I of England. He was accommodated at Eltham Palace. Drebbel worked there at the masques, that were performed for the court, he was attached to the court of young Renaissance crown-prince Henry. He astonished the court with his optical instruments, his fame circulated through the courts of Europe. In October 1610 Drebbel and his family moved to Prague on invitation of Emperor Rudolf II, preoccupied with the arts and occult sciences. Here again Drebbel demonstrated his inventions; when in 1611 Rudolf II was stripped of all effective power by his younger brother Archduke Matthias, Drebbel was imprisoned for about a year. After Rudolf's death in 1612, Drebbel went back to London, his patron prince Henry had died and Drebbel was in financial trouble. With his glass-grinding machine he manufactured optical instruments and compound microscopes with two convex lenses, for which there was a constant demand. In 1622 Constantijn Huygens stayed as a diplomat for more than one year in England.
It is quite possible that he learned the art of glass grinding at this time from Drebbel, that he passed this knowledge to his second son Christiaan Huygens, who became a prominent Dutch mathematician and scientist. The English natural philosopher Robert Hooke may have learned the art of glass grinding from his acquaintance Johannes Sibertus Kuffler, the son-in-law of Drebbel. Towards the end of his life, in 1633, Drebbel was involved in a plan to drain the Fens around Cambridge, while living in near-poverty running an ale house in England, he died in London. In keeping with traditional Mennonite practice, Drebbel's estate was split between his four living children at the time of his death; the Edison of his era, Drebbel was innovator. His constructions and innovations cover measurement and control technology, optics, chemistry and pyrotechnics. Along with Staten General he registered several patents, he wrote essays about his experiments with air pressure and made beautiful engravings. He was involved in making theater props, moving statues and in plans to build a new theater in London.
He worked on producing torpedoes, naval mines, detonators with that used glass Batavian tears, worked on fulminating gold as an explosive. He was known for his Perpetuum Mobile, built an incubator for eggs and a portable stove/oven with an optimal use of fuel, able to keep the heat on a constant temperature by means of a regulator/thermostat, he designed a solar energy system for London, demonstrated air-conditioning, made lightning and thunder ‘on command’, developed fountains and a fresh water supply for the city of Middelburg. He was involved in the draining of the moors around Cambridge, developed a predecessors of the barometer and thermometer, a harpsichords that played on solar energy. Drebbel's most famous written work was Een kort Tractaet van de Natuere der Elementen, he was involved in the invention of mercury fulminate. He discovered that mixtures of “spiritus vini” with mercury and silver in “aqua fortis” could explode. Drebbel invented a chicken incubator and a mercury thermostat which automatically kept it stable at a constant temperature.
He developed and demonstrated a working air conditioning system. The invention of a working thermometer is credited to Drebbel; the story goes that, while making a coloured liquid for a thermometer Cornelis dropped a flask of aqua regia on a tin window sill, discovered that stannous chloride makes the colour of carmine much brighter and more durable. Although Cornelis did not make much money from his work, his daughters Anna and Catharina and his sons-in-law Abraham and Johannes Sibertus Kuffler set up a successful dye works. One was set up in 1643 in Bow and the resulting colour was called bow dye; the recipe for "colour Kufflerianus" was kept a family secret, the new bright red colour was popular in Europe. Develops an automatic precision lens-grinding machine, builds improved telescopes, constructs
Mode of transport
Means of transport is a term used to distinguish different means of conveyance. The different modes of transport are air and land transport, which includes Rails or railways and off-road transport. Other modes exist, including pipelines, cable transport, space transport. Human-powered transport and animal-powered transport are sometimes regarded as their own mode, but never fall into the other categories. In general, transportation is used for the movement of people and other things; each mode of transport has a fundamentally different technological solution, some require a separate environment. Each mode has its own infrastructure and operations. Animal-powered transport is the use of working animals for the movement of goods. Humans may ride some of the animals directly, use them as pack animals for carrying goods, or harness them, alone or in teams, to pull sleds or wheeled vehicles. A fixed-wing aircraft airplane, is a heavier-than-air flight vehicle, in which the special geometry of the wing generates lift.
Fixed-wing aircraft ranges from small trainers and recreational aircraft to large airliners and military cargo aircraft. For short distances or in places without runways, helicopters can be practical. Air transport is the fastest method of transport,made by Ayush Commercial jets reach speeds of up to 955 kilometres per hour and a higher ground speed if there is a jet stream tailwind, while piston-powered general aviation aircraft may reach up to 555 kilometres per hour or more; this celerity comes with higher cost and energy use, aviation's impacts to the environment and the global climate require consideration when comparing modes of transportation. The Intergovernmental Panel on Climate Change estimates a commercial jet's flight to have some 2-4 times the effect on the climate than if the same CO2 emissions were made at ground level, because of different atmospheric chemistry and radiative forcing effects at the higher altitude. U. S. airlines alone burned about 16.2 billion gallons of fuel during the twelve months between October 2013 and September 2014.
WHO estimates that globally as many as 500,000 people at a time are on planes. The global trend has been for increasing numbers of people to travel by air, individually to do so with increasing frequency and over longer distances, a dilemma that has the attention of climate scientists and other researchers, the press, the World Wide Web; the issue of impacts from frequent travel by air because of the longer distances that are covered in one or a few days, is called hypermobility and has been a topic of research and governmental concern for many years. Human powered transport, a form of sustainable transportation, is the transport of people and/or goods using human muscle-power, in the form of walking and swimming. Modern technology has allowed machines to enhance human power. Human-powered transport remains popular for reasons of cost-saving, physical exercise, environmentalism. Although humans are able to walk without infrastructure, the transport can be enhanced through the use of roads when using the human power with vehicles, such as bicycles and inline skates.
Human-powered vehicles have been developed for difficult environments, such as snow and water, by watercraft rowing and skiing. Land transport covers all land-based transportation systems that provide for the movement of people and services. Land transport plays a vital role in linking communities to each other. Land transport is a key factor in urban planning, it consists of 2 kinds and road. Now, some websites allow to combine different land transport to facilitate mobility. Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail track, known as a railway or railroad; the rails are anchored perpendicular to railroad train consists of one or more connected vehicles that run on the rails. Propulsion is provided by a locomotive, that hauls a series of unpowered cars, that can carry passengers or freight; the locomotive can be powered by electricity supplied by trackside systems. Alternatively, some or all the cars can be known as a multiple unit.
A train can be powered by horses, gravity and gas turbines. Railed vehicles move with much less friction than rubber tires on paved roads, making trains more energy efficient, though not as efficient as ships. Intercity trains are long-haul services connecting cities. Regional and commuter trains feed cities from suburbs and surrounding areas, while intra-urban transport is performed by high-capacity tramways and rapid transits making up the backbone of a city's public transport. Freight trains traditionally used box cars, unloading of the cargo. Since the 1960s, container trains have become the dominant solution for general freight, while large quantities of bulk are transported by dedicated trains. A road is an identifiable route of travel surfaced with gravel, asphalt or concrete, supporting land passage by foot or by a number of vehicles; the most common road vehicle in the developed world is the automobile, a wheeled passenger vehicle that carries its own motor. As of 2002, there were 591 million automobiles worldwide.
Other users of roads include
Blaise Pascal was a French mathematician, inventor and Catholic theologian. He was a child prodigy, educated by his father, a tax collector in Rouen. Pascal's earliest work was in the natural and applied sciences where he made important contributions to the study of fluids, clarified the concepts of pressure and vacuum by generalising the work of Evangelista Torricelli. Pascal wrote in defence of the scientific method. In 1642, while still a teenager, he started some pioneering work on calculating machines. After three years of effort and 50 prototypes, he built 20 finished machines over the following 10 years, establishing him as one of the first two inventors of the mechanical calculator. Pascal was an important mathematician, helping create two major new areas of research: he wrote a significant treatise on the subject of projective geometry at the age of 16, corresponded with Pierre de Fermat on probability theory influencing the development of modern economics and social science. Following Galileo Galilei and Torricelli, in 1647, he rebutted Aristotle's followers who insisted that nature abhors a vacuum.
Pascal's results caused many disputes before being accepted. In 1646, he and his sister Jacqueline identified with the religious movement within Catholicism known by its detractors as Jansenism. Following a religious experience in late 1654, he began writing influential works on philosophy and theology, his two most famous works date from this period: the Lettres provinciales and the Pensées, the former set in the conflict between Jansenists and Jesuits. In that year, he wrote an important treatise on the arithmetical triangle. Between 1658 and 1659, he wrote on its use in calculating the volume of solids. Throughout his life, Pascal was in frail health after the age of 18. Pascal was born in Clermont-Ferrand, in France's Auvergne region, he lost Antoinette Begon, at the age of three. His father, Étienne Pascal, who had an interest in science and mathematics, was a local judge and member of the "Noblesse de Robe". Pascal had the younger Jacqueline and the elder Gilberte. In 1631, five years after the death of his wife, Étienne Pascal moved with his children to Paris.
The newly arrived family soon hired Louise Delfault, a maid who became an instrumental member of the family. Étienne, who never remarried, decided that he alone would educate his children, for they all showed extraordinary intellectual ability his son Blaise. The young Pascal showed an amazing aptitude for science. Of interest to Pascal was a work of Desargues on conic sections. Following Desargues' thinking, the 16-year-old Pascal produced, as a means of proof, a short treatise on what was called the "Mystic Hexagram", Essai pour les coniques and sent it—his first serious work of mathematics—to Père Mersenne in Paris, it states that if a hexagon is inscribed in a circle the three intersection points of opposite sides lie on a line. Pascal's work was so precocious; when assured by Mersenne that it was, the product of the son and not the father, Descartes dismissed it with a sniff: "I do not find it strange that he has offered demonstrations about conics more appropriate than those of the ancients," adding, "but other matters related to this subject can be proposed that would scarcely occur to a 16-year-old child."In France at that time offices and positions could be—and were—bought and sold.
In 1631, Étienne sold his position as second president of the Cour des Aides for 65,665 livres. The money was invested in a government bond which provided, if not a lavish certainly a comfortable income which allowed the Pascal family to move to, enjoy, Paris, but in 1638 Richelieu, desperate for money to carry on the Thirty Years' War, defaulted on the government's bonds. Étienne Pascal's worth had dropped from nearly 66,000 livres to less than 7,300. Like so many others, Étienne was forced to flee Paris because of his opposition to the fiscal policies of Cardinal Richelieu, leaving his three children in the care of his neighbour Madame Sainctot, a great beauty with an infamous past who kept one of the most glittering and intellectual salons in all France, it was only when Jacqueline performed well in a children's play with Richelieu in attendance that Étienne was pardoned. In time, Étienne was back in good graces with the cardinal and in 1639 had been appointed the king's commissioner of taxes in the city of Rouen—a city whose tax records, thanks to uprisings, were in utter chaos.
In 1642, in an effort to ease his father's endless, exhausting calculations, recalculations, of taxes owed and paid, not yet 19, constructed a mechanical calculator capable of addition and subtraction, called Pascal's calculator or the Pascaline. Of the eight Pascalines known to have survived, four are held by the Musée des Arts et Métiers in Paris and one more by the Zwinger museum in Dresden, exhibit two of his original mechanical calculators. Although these machines are pioneering forerunners to a further 400 years of development of mechanical methods of calculation, in a sense to the field of computer engineering, the calculator failed to be a great commercial success; because it was still quite cumbersome to use in practice, but primarily because it was extraordinarily expensive, the Pascaline became li
Aviation, or air transport, refers to the activities surrounding mechanical flight and the aircraft industry. Aircraft includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as balloons and airships. Aviation began in the 18th century with the development of the hot air balloon, an apparatus capable of atmospheric displacement through buoyancy; some of the most significant advancements in aviation technology came with the controlled gliding flying of Otto Lilienthal in 1896. Since that time, aviation has been technologically revolutionized by the introduction of the jet which permitted a major form of transport throughout the world; the word aviation was coined by the French writer and former naval officer Gabriel La Landelle in 1863. He derived the term from the verb avier, itself derived from the Latin word avis and the suffix -ation. There are early legends of human flight such as the stories of Icarus in Greek myth and Jamshid and Shah Kay Kāvus in Persian myth.
Somewhat more credible claims of short-distance human flights appear, such as the flying automaton of Archytas of Tarentum, the winged flights of Abbas ibn Firnas, Eilmer of Malmesbury, the hot-air Passarola of Bartholomeu Lourenço de Gusmão. The modern age of aviation began with the first untethered human lighter-than-air flight on November 21, 1783, of a hot air balloon designed by the Montgolfier brothers; the practicality of balloons was limited. It was recognized that a steerable, or dirigible, balloon was required. Jean-Pierre Blanchard flew the first human-powered dirigible in 1784 and crossed the English Channel in one in 1785. Rigid airships became the first aircraft to transport passengers and cargo over great distances; the best known aircraft of this type were manufactured by the German Zeppelin company. The most successful Zeppelin was the Graf Zeppelin, it flew over one million miles, including an around-the-world flight in August 1929. However, the dominance of the Zeppelins over the airplanes of that period, which had a range of only a few hundred miles, was diminishing as airplane design advanced.
The "Golden Age" of the airships ended on May 6, 1937 when the Hindenburg caught fire, killing 36 people. The cause of the Hindenburg accident was blamed on the use of hydrogen instead of helium as the lift gas. An internal investigation by the manufacturer revealed that the coating used in the material covering the frame was flammable and allowed static electricity to build up in the airship. Changes to the coating formulation reduced the risk of further Hindenburg type accidents. Although there have been periodic initiatives to revive their use, airships have seen only niche application since that time. In 1799, Sir George Cayley set forth the concept of the modern airplane as a fixed-wing flying machine with separate systems for lift and control. Early dirigible developments included machine-powered propulsion, rigid frames and improved speed and maneuverability There are many competing claims for the earliest powered, heavier-than-air flight; the first recorded powered flight was carried out by Clément Ader on October 9, 1890 in his bat-winged self-propelled fixed-wing aircraft, the Ader Éole.
It was the first manned, heavier-than-air flight of a significant distance but insignificant altitude from level ground. Seven years on 14 October 1897, Ader's Avion III was tested without success in front of two officials from the French War ministry; the report on the trials was not publicized until 1910. In November 1906 Ader claimed to have made a successful flight on 14 October 1897, achieving an "uninterrupted flight" of around 300 metres. Although believed at the time, these claims were discredited; the Wright brothers made the first successful powered and sustained airplane flight on December 17, 1903, a feat made possible by their invention of three-axis control. Only a decade at the start of World War I, heavier-than-air powered aircraft had become practical for reconnaissance, artillery spotting, attacks against ground positions. Aircraft began to transport people and cargo as designs grew more reliable; the Wright brothers took aloft the first passenger, Charles Furnas, one of their mechanics, on May 14, 1908.
During the 1920s and 1930s great progress was made in the field of aviation, including the first transatlantic flight of Alcock and Brown in 1919, Charles Lindbergh's solo transatlantic flight in 1927, Charles Kingsford Smith's transpacific flight the following year. One of the most successful designs of this period was the Douglas DC-3, which became the first airliner to be profitable carrying passengers starting the modern era of passenger airline service. By the beginning of World War II, many towns and cities had built airports, there were numerous qualified pilots available; the war brought many innovations to aviation, including the first jet aircraft and the first liquid-fueled rockets. After World War II in North America, there was a boom in general aviation, both private and commercial, as thousands of pilots were released from military service and many inexpensive war-surplus transport and training aircraft became available. Manufacturers such as Cessna and Beechcraft expanded production to provide light aircraft for the new middle-class market.
Turtle was the world's first submersible vessel with a documented record of use in combat. It was built in 1775 by American David Bushnell as a means of attaching explosive charges to ships in a harbor, for use against Royal Navy vessels occupying North American harbors during the American Revolutionary War. Connecticut Governor Jonathan Trumbull recommended the invention to George Washington, who provided funds and support for the development and testing of the machine. Several attempts were made using Turtle to affix explosives to the undersides of British warships in New York Harbor in 1776. All failed, her transport ship was sunk that year by the British with the submarine aboard. Bushnell claimed to have recovered the machine, but its final fate is unknown. Modern replicas of Turtle have been constructed and are on display in the Connecticut River Museum, the U. S. Navy's Submarine Force Library and Museum, the Royal Navy Submarine Museum, the Oceanographic Museum; the American inventor David Bushnell made the idea of a submersible vessel for use in lifting the British naval blockade during the American War of Independence.
Bushnell may have begun studying underwater explosions while at Yale College. By early 1775, he had created a reliable method for detonating underwater explosives, a clockwork connected to a musket firing mechanism a flintlock, adapted for the purpose. After the Battles of Lexington and Concord in April 1775, Bushnell began work near Old Saybrook on a small, individually-manned submersible designed to attach an explosive charge to the hull of an enemy ship, which, he wrote Benjamin Franklin, would be, "Constructed with Great Simplicity and upon Principles of Natural Philosophy."Little is known about the origin and influences for Bushnell's invention. It seems clear Bushnell knew of the work of the Dutch inventor Cornelius Drebbel. According to Dr. Benjamin Gale, a doctor who taught at Yale, the many brass and mechanical parts of the submarine were built by the New Haven clock-maker, silversmith, brass manufacturer and inventor Isaac Doolittle, whose shop was just a half block from Yale. Though Bushnell is given the overall design credit for the Turtle by Gale and others, Doolittle was well known as an "ingenious mechanic", metalworker.
He had both designed and manufactured complicated brass-wheel hall-clocks, a mahogany printing-press in 1769, brass compasses, surveying instruments. He founded and owned a brass foundry where he cast bells. At the start of the American Revolution, the wealthy and patriotic Doolittle built a gunpowder mill with two partners in New Haven to support the war, was sent by the Connecticut government to prospect for lead. Though the design of the Turtle was shrouded in secrecy, based on his mechanical engineering expertise and previous experience in design and manufacturing, it seems Doolittle designed and crafted the brass and the moving parts of the Turtle, including the propulsion system, the navigation instruments, the brass foot operated water-ballast and forcing pumps, the depth gauge and compass, the brass crown hatch, the clockwork detonator for the mine, the hand operated propeller crank and foot-driven treadle with flywheel. According to a letter from Dr. Benjamin Gale to Benjamin Franklin, Doolittle designed the mine attachment mechanism, "those Parts which Conveys the Powder, secures the same to the Bottom of the Ship".
The most important innovation in the Turtle was the propeller, as it was the first known use of one in a watercraft: it was described as an "oar for rowing forward or backward", with "no precedent" design and in a letter by Dr. Benjamin Gale to Silas Dean as "a pair of oars fixed like the two opposite arms of a windmill" and as "two oars or paddles" that were "like the arms of a windmill...twelve inches long, about four wide." As it was brass, it was thus designed and forged by Doolittle. Doolittle likely provided the scarce commodities of gunpowder and lead ballast as well; the wealthy Doolittle, nearly 20 years older than the Yale student Bushnell, was a founder and long time Warden of Trinity Episcopal Church on the Green, was in charge of New Haven's port inspection and beacon-alarm systems – suggesting that Doolittle provided much of the political and financial leadership in building the Turtle as well as its brass and moving parts. In making the hull, Bushnell enlisted the services of several skilled artisans, including his brother the farmer Ezra Bushnell and ship's carpenter Phineas Pratt, like David Bushnell, from Saybrook.
The hull was "constructed of oak, somewhat like a barrel and bound by heavy wrought-iron hoops." The shape of the hull, Gale informed Silas Deane, "has the nearest resemblance to the two upper shells of a Tortoise joined together." Named for its shape, Turtle resembled a large clam as much as a turtle. It dived by allowing water into a bilge tank at the bottom of the vessel and ascended by pushing water out through a hand pump, it was propelled vertically and horizontally by hand-cranked propellers. It had 200 pounds of lead aboard, which could be released in a moment to increase buoyancy. Manned and operated by one person, the vessel contained enough air for about thirty minutes and had a speed in calm water of about 3 mph. Six small pieces of thick glass in the top of the submarine provided natural light; the i