National Museum of Australia
The National Museum of Australia, in the national capital Canberra and interprets Australia's social history, exploring the key issues and events that have shaped the nation. It was formally established by the National Museum of Australia Act 1980; the museum did not have a permanent home until 11 March 2001, when a purpose-built museum building was opened. The museum profiles 50,000 years of Indigenous heritage, settlement since 1788 and key events including Federation and the Sydney 2000 Olympics; the museum holds the world's largest collection of Aboriginal bark paintings and stone tools, the heart of champion racehorse Phar Lap and the Holden prototype No. 1 car. The museum develops and travels exhibitions on subjects ranging from bushrangers to surf lifesaving; the National Museum of Australia Press publishes a wide range of books and journals. The museum's Research Centre takes a cross-disciplinary approach to history, ensuring the museum is a lively forum for ideas and debate about Australia's past and future.
The museum's innovative use of new technologies has been central to its growing international reputation in outreach programming with regional communities. From 2003 to 2008, the museum hosted a student political forum; the museum is located on Acton Peninsula in the suburb of Acton, next to the Australian National University. The peninsula on Lake Burley Griffin was the home of the Royal Canberra Hospital, demolished in tragic circumstances on 13 July 1997; as designed by architect Howard Raggatt, the museum building is based on a theme of knotted ropes, symbolically bringing together the stories of Australians. The architects stated: "We liked to think that the story of Australia was not one, but many tangled together. Not an authorized version but a puzzling confluence; the building is meant to be the centre of a knot, with trailing ropes or strips extending from the building. The most obvious of these extensions forms a large loop before becoming a walkway which extends past the neighbouring AIATSIS building ending in a large curl, as if a huge ribbon has haphazardly unrolled itself along the ground.
Known as the "Uluru Axis" because it aligns with the central Australian natural landmark, the ribbon symbolically integrates the site with the Canberra city plan by Walter Burley Griffin and the spiritual heart of indigenous Australia. The shape of the main entrance hall continues this theme: it is as though the otherwise rectangular building has been built encasing a complex knot which does not quite fit inside the building, the knot taken away; the non-symmetrical complex is designed to not look like a museum, with startling colours and angles, unusual spaces and unpredictable projections and textures. Though hard to categorise, the building can be seen as an example of Charles Jenck's "new paradigm"; some characteristics of Deconstructivism can be identified. The organising concept of the scheme using the idea of a "tangled vision" incorporates a variety of references including: Bea Maddock's "Philosophy Tape" Jackson Pollock's "Blue Poles" boolean string, a knot, Ariadne's thread the Aboriginal Dreamtime story of the Rainbow Serpent making the land.
The building's architecture is thus meant to imply that the story of Australia is not one story, but many stories tangled together. The building refers to or quotes other buildings: a Burley-Griffin designed cloister at Newman College in Melbourne the Sydney Opera House – both the parts designed by Jørn Utzon, sections designed by the other architects the shell curves of Félix Candela the Hall is evocative of Eero Saarinen's terminal at the J F Kennedy Airport in New York the arc is like a piece of work by Richard Serra the Garden of Australian Dreams is meant to evoke a range of different cartographies the walls use selected fragments of the word Eternity – evoking the story of Arthur Stace who for thirty years chalked this single word on the pavements of Sydney the most controversial quotation is a reference to the Daniel Libeskind's Jewish Museum Berlin, Germany which opened in 1999 The plan of the National Museum of Australia incorporates an exact copy of the lightning-flash zigzag that Libeskind created for the Berlin Museum by breaking a star of David.
The Bulletin magazine first publicly raised allegations of plagiarism in June 2000. Libeskind was reported to be angry with the copying. Raggatt's defence against plagiarism was; the director of the museum, Dawn Casey, claimed in the press that she and her council were not aware of this symbolism when they approved the plan. The exterior of the building is covered in anodised aluminium panels. Many of the panels include words written in braille and other decorative devices. Among the messages are "mate" and "she'll be right". Included were such controversial words and phrases as "sorry" and "forgive us our genocide"; these more controversial messages have been obscured with silver discs being attached to the surface making the braille illegible. Among the phrases in braille are the words "Resurrection city"; the phrase may refer to the clearing of the former Canberra Hospital to make way for the museum or it could be a reference to reconciliation between Indigenous Australians and European settlers.
The phrase is used as a label in tiles on another of Raggett's buildings, the Storey Hall in Melbourne. Raggett says of that message: "I guess that tries to be some big sort of theme for this building as well and its sort of set of memories."It was built by Bovis Lend Lease and completed in 2001. A severe thunderstorm hit Canberra on the afternoon of
A patent is a form of intellectual property. A patent gives its owner the right to exclude others from making, using and importing an invention for a limited period of time twenty years; the patent rights are granted in exchange for an enabling public disclosure of the invention. In most countries patent rights fall under civil law and the patent holder needs to sue someone infringing the patent in order to enforce his or her rights. In some industries patents are an essential form of competitive advantage; the procedure for granting patents, requirements placed on the patentee, the extent of the exclusive rights vary between countries according to national laws and international agreements. However, a granted patent application must include one or more claims that define the invention. A patent may include many claims; these claims must meet relevant patentability requirements, such as novelty and non-obviousness. Under the World Trade Organization's TRIPS Agreement, patents should be available in WTO member states for any invention, in all fields of technology, provided they are new, involve an inventive step, are capable of industrial application.
There are variations on what is patentable subject matter from country to country among WTO member states. TRIPS provides that the term of protection available should be a minimum of twenty years; the word patent originates from the Latin patere, which means "to lay open". It is a shortened version of the term letters patent, an open document or instrument issued by a monarch or government granting exclusive rights to a person, predating the modern patent system. Similar grants included land patents, which were land grants by early state governments in the USA, printing patents, a precursor of modern copyright. In modern usage, the term patent refers to the right granted to anyone who invents something new and non-obvious; some other types of intellectual property rights are called patents in some jurisdictions: industrial design rights are called design patents in the US, plant breeders' rights are sometimes called plant patents, utility models and Gebrauchsmuster are sometimes called petty patents or innovation patents.
The additional qualification utility patent is sometimes used to distinguish the primary meaning from these other types of patents. Particular species of patents for inventions include biological patents, business method patents, chemical patents and software patents. Although there is some evidence that some form of patent rights was recognized in Ancient Greece in the Greek city of Sybaris, the first statutory patent system is regarded to be the Venetian Patent Statute of 1474. Patents were systematically granted in Venice as of 1474, where they issued a decree by which new and inventive devices had to be communicated to the Republic in order to obtain legal protection against potential infringers; the period of protection was 10 years.. As Venetians emigrated, they sought similar patent protection in their new homes; this led to the diffusion of patent systems to other countries. The English patent system evolved from its early medieval origins into the first modern patent system that recognised intellectual property in order to stimulate invention.
By the 16th century, the English Crown would habitually abuse the granting of letters patent for monopolies. After public outcry, King James I of England was forced to revoke all existing monopolies and declare that they were only to be used for "projects of new invention"; this was incorporated into the Statute of Monopolies in which Parliament restricted the Crown's power explicitly so that the King could only issue letters patent to the inventors or introducers of original inventions for a fixed number of years. The Statute became the foundation for developments in patent law in England and elsewhere. Important developments in patent law emerged during the 18th century through a slow process of judicial interpretation of the law. During the reign of Queen Anne, patent applications were required to supply a complete specification of the principles of operation of the invention for public access. Legal battles around the 1796 patent taken out by James Watt for his steam engine, established the principles that patents could be issued for improvements of an existing machine and that ideas or principles without specific practical application could legally be patented.
Influenced by the philosophy of John Locke, the granting of patents began to be viewed as a form of intellectual property right, rather than the obtaining of economic privilege. The English legal system became the foundation for patent law in countries with a common law heritage, including the United States, New Zealand and Australia. In the Thirteen Colonies, inventors could obtain patents through petition to a given colony's legislature. In 1641, Samuel Winslow was granted the first patent in North America by the Massachusetts General Court for a new process for making salt; the modern French patent system was created during the Revolution in 1791. Patents were granted without examination. Patent costs were high. Importation patents protected new devices coming from foreign countries; the patent law was revised in 1844 - patent cost was lowered and importation patents were abolished. The first Patent Act of the U. S. Congress was passed on April 10, 1790, titled "An Act to promote the progress of
A headlamp is a lamp attached to the front of a vehicle to light the road ahead. Headlamps are often called headlights, but in the most precise usage, headlamp is the term for the device itself and headlight is the term for the beam of light produced and distributed by the device. Headlamp performance has improved throughout the automobile age, spurred by the great disparity between daytime and nighttime traffic fatalities: the US National Highway Traffic Safety Administration states that nearly half of all traffic-related fatalities occur in the dark, despite only 25% of traffic travelling during darkness. Other vehicles, such as trains and aircraft, are required to have headlamps. Bicycle headlamps are used on bicycles, are required in some jurisdictions, they can be powered by a battery or a small generator mechanically integrated into the workings of the bicycles. The first horseless carriages used carriage lamps, which proved unsuitable for travel at speed; the earliest lights used candles as the most common type of fuel.
The earliest headlamps, fueled by acetylene or oil, operated from the late 1880s. Acetylene lamps were popular because the flame is resistant to wind and rain; the first electric headlamps were introduced in 1898 on the Columbia Electric Car from the Electric Vehicle Company of Hartford and were optional. Two factors limited the widespread use of electric headlamps: the short life of filaments in the harsh automotive environment, the difficulty of producing dynamos small enough, yet powerful enough to produce sufficient current. A number of manufacturers offered "Prest-O-Lite" acetylene lights as standard equipment for 1904, Peerless made electric headlamps standard in 1908. A Birmingham firm called Pockley Automobile Electric Lighting Syndicate marketed the world's first electric car-lights as a complete set in 1908, which consisted of headlamps and tail lights that were powered by an eight-volt battery. In 1912 Cadillac integrated their vehicle's Delco electrical ignition and lighting system, forming the modern vehicle electrical system.
The Guide Lamp Company introduced "dipping" headlamps in 1915, but the 1917 Cadillac system allowed the light to be dipped using a lever inside the car rather than requiring the driver to stop and get out. The 1924 Bilux bulb was the first modern unit, having the light for both low and high beams of a headlamp emitting from a single bulb. A similar design was introduced in 1925 by Guide Lamp called the "Duplo". In 1927 the foot-operated dimmer switch or dip switch was introduced and became standard for much of the century. 1933–1934 Packards featured tri-beam headlamps, the bulbs having three filaments. From highest to lowest, the beams were called "country passing", "country driving" and "city driving"; the 1934 Nash used a three-beam system, although in this case with bulbs of the conventional two-filament type, the intermediate beam combined low beam on the driver's side with high beam on the passenger's side, so as to maximise the view of the roadside while minimizing glare toward oncoming traffic.
The last vehicles with a foot-operated dimmer switch were the 1991 Ford F-Series and E-Series vans. Fog lamps were new for 1938 Cadillacs, their 1954 "Autronic Eye" system automated the selection of high and low beams. Directional lighting, using a switch and electromagnetically shifted reflector to illuminate the curbside only, was introduced in the rare, one-year-only 1935 Tatra. Steering-linked lighting was featured on the 1947 Tucker Torpedo's center-mounted headlight, was popularized by the Citroen DS; this made it possible to turn the light in the direction of travel when the steering wheel turned, is now adopted technology. The standardized 7-inch round sealed-beam headlamp, one per side, was required for all vehicles sold in the United States from 1940 freezing usable lighting technology in place until the 1970s for Americans. In 1957 the law changed to allow smaller 5.75-inch round sealed beams, two per side of the vehicle, in 1974 rectangular sealed beams were permitted as well. Britain and some other Commonwealth countries, as well as Japan and Sweden made extensive use of 7-inch sealed beams, though they were not mandated as they were in the United States.
This headlamp format was not accepted in continental Europe, which found replaceable bulbs and variations in the size and shape of headlamps useful in car design. This led to different front-end designs for each side of the Atlantic for decades. Technology moved forward in the rest of the world. In 1962 a European consortium of bulb- and headlamp-makers introduced the first halogen lamp for vehicle headlamp use, the H1. Shortly thereafter headlamps using the new light source were introduced in Europe; these were prohibited in the US, where standard-size sealed beam headlamps were mandatory and intensity regulations were low. US lawmakers faced pressure to act, due both to lighting effectiveness and to vehicle aerodynamics/fuel savings. High-beam peak intensity, capped at 140,000 candela per side of the car in Europe, was limited in the United States to 37,500 candela on each side of the car until 1978, when the limit was raised to 75,000. An increase in high-beam intensity to take advantage of the higher allowance could not be achieved without a move to halogen technology, so sealed-beam headlamps with internal halogen burners became available for use on 1979 models in the United States.
As of 2010 halogen sealed beams dominate the sealed-beam market, which has declined steeply since replaceable-bulb headlamps were permitted in 1983. High-intensity discharge systems appeared in the early 1990s, first in the BMW 7 Series. 1996's Lincoln Mark VIII was an early Americ
A light fixture, light fitting, or luminaire is an electrical device that contains an electric lamp that provides illumination. All light fixtures have one or more lamps; the lamps may be in sockets for easy replacement—or, in the case of some LED fixtures, hard-wired in place. Fixtures may have a switch to control the light, either attached to the lamp body or attached to the power cable. Permanent light fixtures, such as dining room chandeliers, may have no switch on the fixture itself, but rely on a wall switch. Fixtures require an electrical connection to a power source AC mains power, but some run on battery power for camping or emergency lights. Permanent lighting fixtures are directly wired. Movable lamps have a cord that plugs into a wall socket. Light fixtures may have other features, such as reflectors for directing the light, an aperture, an outer shell or housing for lamp alignment and protection, an electrical ballast or power supply, a shade to diffuse the light or direct it towards a workspace.
A wide variety of special light fixtures are created for use in the automotive lighting industry, aerospace and medicine sectors. Portable light fixtures are called lamps, as in table lamp or desk lamp. In technical terminology, the lamp is the light source, which, in casual terminology, is called the light bulb; the International Electrotechnical Commission recommends the term luminaire for technical use. Fixture manufacturing began soon after production of the incandescent light bulb; when practical uses of fluorescent lighting were realized after 1924, the three leading companies to produce various fixtures were Lightolier, Artcraft Fluorescent Lighting Corporation, Globe Lighting in the United States. Light fixtures are classified by how the fixture is installed, the light lamp type. Table lamp fixtures, standard lamp fixtures, office task light luminaires. Balanced-arm lamp is a spot light with an adjustable arm such as anglepoise or Luxo L1. Gooseneck lamp Nightlight Floor Lamp Torch lamp or torchières are floor lamps with an upward facing shade.
They provide general lighting to the rest of the room. Gooseneck lamp Bouillotte lamp: see Bouillotte Ceiling Dome – Also called the light source are hidden behind a translucent dome made of glass, with some combination of frosting and surface texturing to diffuse the light; these can be flush-mount fixtures mounted into the ceiling, or semi-flush fixtures separated by a small distance. Open ceiling dome – the translucent dome is suspended a short distance below the ceiling by a mechanism, hidden with the exception of a screw-knob or other device appearing on the outer dome face, pulling this knob releases the dome Enclosed ceiling dome The translucent dome mates with a ring, mounted flush with the ceiling Recessed light – the protective housing is concealed behind a ceiling or wall, leaving only the fixture itself exposed; the ceiling-mounted version is called a downlight. "Cans" with a variety of lamps – this term is jargon for inexpensive downlighting products that are recessed into the ceiling, or sometimes for uplights placed on the floor.
The name comes from the shape of the housing. The term "pot lights" is used in Canada and parts of the US. Cove light – recessed into the ceiling in a long box against a wall. Troffer – recessed fluorescent light fixtures rectangular in shape to fit into a drop ceiling grid. Surface-mounted light – the finished housing is exposed, not flush with surface Chandelier Pendant light – suspended from the ceiling with a chain or pipe Sconce – provide up or down lights. Track lighting fixture – individual fixtures can be positioned anywhere along the track, which provides electric power. Under-cabinet light – mounted below kitchen wall cabinets Display Case or Showcase light – shows merchandise on display within an enclosed case such as jewelry, grocery stores, chain stores. Ceiling fan – May sometimes have a light referred to as a light kit mounted to it. Emergency lighting or exit sign – connected to a battery backup or to an electric circuit that has emergency power if the mains power fails High- and low-bay lighting – used for general lighting for industrial buildings and big-box stores Strip lights or Industrial lighting – long lines of fluorescent lamps used in a warehouse or factory Outdoor lighting and landscape lighting – used to illuminate walkways, parking lots, building exteriors and architectural details and parks.
Outdoor light fixtures can include forms similar to indoor lighting, such as pendants, flush or close-to-ceiling light fixtures, wall-mounted lanterns and dome lights. High-mast pole – or stanchion-mounted – for landscape and parking lots Bollard – A type of architectural outdoor lighting, a short, upright ground-mounted unit used to provide cutoff type illumination for egress lighting, to light walkways, steps, or other pathways. Solar lamp Street light Yard light Accent light – Any directional light that highlights an object or attracts attention to a particular area Background light – for use in video production Blacklight Christmas lights – called fairy lights or twinkle lights and are used at Christmas and other holidays for decoration. Emergency light – provides minimal light to a building during a power outage. Exit sign Flood light Safelight Safety lamp Searchlight Security lighting Step light Strobe ligh
Soot is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is extended to include the residual pyrolysed fuel particles such as coal, charred wood, petroleum coke that may become airborne during pyrolysis and that are more properly identified as cokes or char. Soot causes various types of lung disease. Soot as an airborne contaminant in the environment has many different sources, all of which are results of some form of pyrolysis, they include soot from coal burning, internal-combustion engines, power-plant boilers, hog-fuel boilers, ship boilers, central steam-heat boilers, waste incineration, local field burning, house fires, forest fires and furnaces. These exterior sources contribute to the indoor environment sources such as smoking of plant matter, oil lamps, quartz/halogen bulbs with settled dust, exhaust emissions from vehicles, defective furnaces. Soot in low concentrations is capable of darkening surfaces or making particle agglomerates, such as those from ventilation systems, appear black.
Soot is the primary cause of "ghosting", the discoloration of walls and ceilings or walls and flooring where they meet. It is responsible for the discoloration of the walls above baseboard electric heating units; the formation of soot depends on the fuel composition. The rank ordering of sooting tendency of fuel components is: naphthalenes → benzenes → aliphatics. However, the order of sooting tendencies of the aliphatics varies depending on the flame type; the difference between the sooting tendencies of aliphatics and aromatics is thought to result from the different routes of formation. Aliphatics appear to first form acetylene and polyacetylenes, a slow process. Intergovernmental Panel on Climate Change adopted the description of soot given by Charlson and Heintzenberg as, “Particles formed during the quenching of gases at the outer edge of flames of organic vapours, consisting predominantly of carbon, with lesser amounts of oxygen and hydrogen present as carboxyl and phenolic groups and exhibiting an imperfect graphitic structure”Formation of soot is a complex process, an evolution of matter in which a number of molecules undergo many chemical and physical reactions within a few milliseconds.
Soot is a powder-like form of amorphous carbon. Gas-phase soot contains polycyclic aromatic hydrocarbons; the PAHs in soot are known mutagens and are classified as a "known human carcinogen" by the International Agency for Research on Cancer. Soot forms during incomplete combustion from precursor molecules such as acetylene, it consists of agglomerated nanoparticles with diameters between 30 nm. The soot particles can be mixed with metal oxides and with minerals and can be coated with sulfuric acid. Many details of soot formation chemistry remain unanswered and controversial, but there have been a few agreements: Soot begins with some precursors or building blocks. Nucleation of heavy molecules occurs to form particles. Surface growth of a particle proceeds by adsorption of gas phase molecules. Coagulation happens via reactive particle–particle collisions. Oxidation of the molecules and soot particles reduces soot formation. Soot diesel exhaust pollution, accounts for over one quarter of the total hazardous pollution in the air.
Among these diesel emission components, particulate matter has been a serious concern for human health due to its direct and broad impact on the respiratory organs. In earlier times, health professionals associated PM10 with chronic lung disease, lung cancer, influenza and increased mortality rate. However, recent scientific studies suggest that these correlations be more linked with fine particles and ultra-fine particles. Long-term exposure to urban air pollution containing soot increases the risk of coronary artery disease. Diesel exhaust. In human experimental studies using an exposure chamber setup, DE has been linked to acute vascular dysfunction and increased thrombus formation; this serves as a plausible mechanistic link between the described association between particulate matter air pollution and increased cardiovascular morbidity and mortality. Soot tends to form in chimneys in domestic houses possessing one or more fireplaces. If a large deposit collects in one, it can create a chimney fire.
Regular cleaning by a chimney sweep should eliminate the problem. Soot mechanism is difficult to model mathematically because of the large number of primary components of diesel fuel, complex combustion mechanisms, the heterogeneous interactions during soot formation. Soot models are broadly categorized into three subgroups: empirical, semi-empirical, detailed theoretical mechanisms are available in the literature for soot models. Empirical models use correlations of experimental data to predict trends in soot production. Empirical models are easy to implement and provide excellent correlations for a given set of operating conditions. However, empirical models cannot be used to investigate the underlying mechanisms of so
A paddle steamer is a steamship or riverboat powered by a steam engine that drives paddle wheels to propel the craft through the water. In antiquity, paddle wheelers followed the development of poles and sails, where the first uses were wheelers driven by animals or humans. In the early 19th century, paddle wheels were the predominant way of propulsion for steam-powered boats. In the late 19th century, paddle propulsion was superseded by the screw propeller and other marine propulsion systems that have a higher efficiency in rough or open water. Paddle wheels continue to be used by small pedal-powered paddle boats and by some ships that operate tourist voyages; the latter are powered by diesel engines. The paddle wheel is a large steel framework wheel; the outer edge of the wheel is fitted with regularly-spaced paddle blades. The bottom quarter or so of the wheel travels underwater. An engine rotates the paddle wheel in the water to produce backward as required. More advanced paddle wheel designs feature feathering methods that keep each paddle blade closer to vertical while in the water to increase efficiency.
The upper part of a paddle wheel is enclosed in a paddlebox to minimise splashing. There are two types of paddle wheel steamer, a sternwheeler with a single wheel on the rear, a sidewheeler with one on each side. Both were used as riverboats in the United States; some still operate for example on the Mississippi River. Although the first sternwheelers were invented in Europe, they saw the most service in North America on the Mississippi River. Enterprise was built at Brownsville, Pennsylvania, in 1814 as an improvement over the less efficient side wheelers; the second sternwheeler built, Washington of 1816, had two decks and served as the prototype for all subsequent steamboats of the Mississippi, including those made famous in Mark Twain's book Life on the Mississippi. Sidewheelers are used as coastal craft. Though the side wheels and enclosing sponsons make them wider than sternwheelers, they may be more maneuverable, since they can sometimes move the paddles at different speeds, in opposite directions.
This extra maneuverability makes sidewheelers popular on the narrower, winding rivers of the Murray-Darling system in Australia, where a number still operate. European sidewheelers, such as PS Waverley, connect the wheels with solid drive shafts that limit maneuverability and give the craft a wide turning radius; some were built with paddle clutches that disengage one or both paddles so they can turn independently. However, wisdom gained from early experience with sidewheelers deemed that they be operated with clutches out, or as solid shaft vessels. Crews noticed that as ships approached the dock, passengers moved to the side of the ship ready to disembark; the shift in weight, added to independent movements of the paddles, could lead to imbalance and potential capsizing. Paddle tugs were operated with clutches in, as the lack of passengers aboard meant that independent paddle movement could be used safely and the added maneuverability exploited to the full. In a simple paddle wheel, where the paddles are fixed around the periphery, power is lost due to churning of the water as the paddles enter and leave the water surface.
Ideally, the paddles should remain vertical while under water. This ideal can be approximated by use of linkages connected to a fixed eccentric; the eccentric is fixed forward of the main wheel centre. It is coupled to each paddle via a lever; the geometry is designed such that the paddles are kept vertical for the short duration that they are in the water. The use of a paddle wheel in navigation appears for the first time in the mechanical treatise of the Roman engineer Vitruvius, where he describes multi-geared paddle wheels working as a ship odometer; the first mention of paddle wheels as a means of propulsion comes from the 4th–5th century military treatise De Rebus Bellicis, where the anonymous Roman author describes an ox-driven paddle-wheel warship: The Italian physician Guido da Vigevano, planning for a new crusade, made illustrations for a paddle boat, propelled by manually turned compound cranks. One of the drawings of the Anonymous Author of the Hussite Wars shows a boat with a pair of paddle-wheels at each end turned by men operating compound cranks.
The concept was improved by the Italian Roberto Valturio in 1463, who devised a boat with five sets, where the parallel cranks are all joined to a single power source by one connecting-rod, an idea adopted by his compatriot Francesco di Giorgio. In 1704, the French physicist Denis Papin constructed the first ship powered by his steam engine, mechanically linked to paddles; this made him the first to construct a steam-powered boat. He has poured the first steam cylinder of the world in the iron foundry Veckerhagen. In 1787 Patrick Miller of Dalswinton invented a double-hulled boat, propelled on the Firth of Forth by men working a capstan that drove paddles on each side. One of the firsts functioning steamships, Palmipède, the first paddle steamer, was built in France in 1774 by Marquis Claude de Jouffroy and his colleagues; the 13-metre steamer with rotating paddles sailed on the Doubs River in June and July 1776. In 1783 a new paddle steamer by de Jouffroy, Pyroscaphe steamed up the river Saône for fifteen minutes before the engine failed.
Bureaucracy and the French Revolution thwarted further progress by de Jouffroy. The next successful attempt at a paddle-driven steam ship was by the Scottish engineer William Symington, who suggested steam power to Patrick Mi
Caving – traditionally known as spelunking in the United States and Canada and potholing in the United Kingdom and Ireland – is the recreational pastime of exploring wild cave systems. In contrast, speleology is the scientific study of the cave environment; the challenges involved in caving vary according to the cave being visited. Cave diving is a distinct, more hazardous, sub-speciality undertaken by a small minority of technically proficient cavers. In an area of overlap between recreational pursuit and scientific study, the most devoted and serious-minded cavers become accomplished at the surveying and mapping of caves and the formal publication of their efforts. In the US, these are private, but in the UK and other European countries, they are published and publicly. Sometimes categorized as an "extreme sport", it is not considered as such by longtime enthusiasts, who may dislike the term for its connotation of disregard for safety. Many caving skills overlap with those involved in urban exploration.
Caving is undertaken for the enjoyment of the outdoor activity or for physical exercise, as well as original exploration, similar to mountaineering or diving. Physical or biological science is an important goal for some cavers, while others are engaged in cave photography. Virgin cave systems comprise some of the last unexplored regions on Earth and much effort is put into trying to locate and survey them. In well-explored regions, the most accessible caves have been explored, gaining access to new caves requires cave digging or cave diving. Caving, in certain areas, has been utilized as a form of eco and adventure tourism. Tour companies have established an industry leading and guiding tours through caves. Depending on the type of cave and the type of tour, the experience could be adventure-based or ecological-based. In many areas, there are tours led through lava tubes by a guiding service. Caving has been described as an "individualist's team sport" by some, as cavers can make a trip without direct physical assistance from others but will go in a group for companionship or to provide emergency help if needed.
Some however consider the assistance cavers give each other as a typical team sport activity. Clay Perry, an American caver of the 1940s, wrote about a group of men and boys who explored and studied caves throughout New England; this group referred to themselves as spelunkers, a term derived from the Latin spēlunca, itself from the Greek σπῆλυγξ spēlynks. This is regarded as the first use of the word in the Americas. Throughout the 1950s, spelunking was the general term used for exploring caves in US English, it was used without any positive or negative connotations, although only outside the US. In the 1960s, the terms spelunking and spelunker began to be considered déclassé among experienced enthusiasts. In 1985, Steve Knutson – editor of the National Speleological Society publication American Caving Accidents – made the following distinction: …Note that I use the term'spelunker' to denote someone untrained and unknowledgeable in current exploration techniques, and'caver' for those who are.
This sentiment is exemplified by bumper stickers and T-shirts displayed by some cavers: "Cavers rescue spelunkers". Outside the caving community, "spelunking" and "spelunkers" predominately remain neutral terms referring to the practice and practitioners, without any respect to skill level. Potholing refers to the act of exploring potholes, a word originating in the north of England for predominantly vertical caves; the base term caving comes from the Latin cavea or caverna, meaning a cave. Caving was pioneered by Édouard-Alfred Martel, who first achieved the descent and exploration of the Gouffre de Padirac, in France, as early as 1889 and the first complete descent of a 110-metre wet vertical shaft at Gaping Gill, in Yorkshire, England, in 1895, he developed his own techniques based on metallic ladders. Martel visited Kentucky and notably Mammoth Cave National Park in October 1912. In the 1920s famous US caver Floyd Collins made important explorations in the area and in the 1930s, as caving became popular, small exploration teams both in the Alps and in the karstic high plateaus of southwest France transformed cave exploration into both a scientific and recreational activity.
Robert de Joly, Guy de Lavaur and Norbert Casteret were prominent figures of that time, surveying caves in Southwest France. During World War II, an alpine team composed of Pierre Chevalier, Fernand Petzl, Charles Petit-Didier and others explored the Dent de Crolles cave system near Grenoble, which became the deepest explored system in the world at that time; the lack of available equipment during the war forced Pierre Chevalier and the rest of the team to develop their own equipment, leading to technical innovation. The scaling-pole, nylon ropes, use of explosives in caves and mechanical rope-ascenders can be directly associated to the exploration of the Dent de Crolles cave system. In 1941, American cavers organized themselves into the National Speleological Society to advance the exploration, conservation and understanding of caves in the United States. American caver Bill Cuddington, known as "Vertical Bill", further developed the single-rope technique in