The Langley Aerodrome was a pioneering but unsuccessful manned, powered flying machine designed at the close of the 19th century by Smithsonian Institution Secretary Samuel Langley. The U. S. Army paid $50,000 for the project in 1898 after Langley's successful flights with small-scale unmanned models two years earlier. Langley coined the word "Aerodrome" and applied it to a series of engine-driven unmanned and manned tandem wing aircraft that were built under his supervision by Smithsonian staff in the 1890s and early 1900s; the term is derived from Greek words meaning "air runner". After a series of unsuccessful tests beginning in 1894, Langley's unmanned steam-driven model "Number 5" made a successful 90-second flight of over 0.5 miles at about 25 miles per hour at a height of 80 feet to 100 feet on May 6, 1896. In November, model "Number 6" flew 1 mile. Both aircraft were launched by catapult from a houseboat in the Potomac River near Quantico, south of Washington, D. C; the flights impressed Assistant Secretary of the Navy Theodore Roosevelt enough for him to assert that "the machine has worked" and to call for the United States Navy to create a four-officer board to study the utility of Langley's "flying machine" in March 1898, the first documented U.
S. Navy expression of interest in aviation; the group approved the idea. Instead, the Board of Ordnance and Fortification of the U. S. Department of War acted on the recommendation and made $50,000 in grants to the Smithsonian for construction of a full-scale man-carrying version. Langley's technical team built a gasoline-powered quarter-scale unmanned model, which flew twice on June 18, 1901, again with an improved engine on August 8, 1903; the full-scale Aerodrome's internal combustion engine generated 53 horsepower, about four times that of the Wright Brothers' gasoline engine of 1903. The Aerodome's other features, however structure and control, left much to be desired; the Aerodrome had a primitive control system that included a cruciform tail and a centrally-mounted rudder. Langley again used, he chose his chief engineer, Charles M. Manly, to ride the aircraft and operate the controls as best he might. On the first flight attempt, October 7, 1903, the craft failed to fly and dropped into the Potomac River after launch.
On the second attempt, December 8, the craft again fell into the river. Rescuers pulled Manly unhurt from the water each time. Langley blamed the calamities on a problem with the launch mechanism, not the aircraft; the real problem lay in his failure to consider the problems of calculating stress on an airframe and correct control of an aircraft. He made no further tests, his experiments became the object of scorn in newspapers and the U. S. Congress. Nine days after the December 8, 1903, the Wright brothers conducted four successful flights near Kitty Hawk, North Carolina. With Smithsonian approval, Glenn Curtiss extensively modified the Aerodrome and made a few short flights in it in 1914, as part of an unsuccessful attempt to bypass the Wright Brothers' patent on aircraft and to vindicate Langley. Based on these flights, the Smithsonian displayed the Aerodrome in its museum as the first heavier-than-air manned, powered aircraft "capable of flight." This action triggered a feud with Orville Wright, who accused the Smithsonian of misrepresenting flying machine history.
Orville backed up his protest by refusing to donate the original 1903 Kitty Hawk Flyer to the Smithsonian, instead donating it to extensive collections of the Science Museum of London in 1928. The dispute ended in 1942 when the Smithsonian published details of the Curtiss modifications to the Aerodrome and recanted its claims for the aircraft. Curtiss called the preparations "restoration" claiming that the only addition to the design was pontoons to support testing on the lake but critics including patent attorney Griffith Brewer called them alterations of the original design. In a June 22, 1914, letter to the New York Times Brewer asked "Why, if the Langley flying machine was a practical flying machine, did not those in charge of the machine try to fly it without alteration?" Brewer questioned the decision to allow someone, found guilty of patent infringement to be chosen to prepare the historic aircraft for tests. Curtiss flew the modified Aerodrome from Keuka Lake, New York, hopping a few feet off the surface of the water several times for no longer than five seconds at a time.
Photos of a bit of daylight beneath the pontoons taken at an additional test conducted closer to shore a few days were published by the media. Two of Langley's scale model Aerodromes survive to this day. Aerodrome No. 5, the first Langley heavier-than-air craft to fly, is on display at the Smithsonian's National Air and Space Museum in Washington, D. C. Aerodrome No. 6 is located at Wesley W. Posvar Hall, University of Pittsburgh, was restored in part by the engineering students. Fabric on the wings and tail is the only new material, although the tail and several wing ribs were rebuilt using vintage wood from the same time period provided by the Smithsonian. Langley had been an astronomy professor at the university before he ascended to the Smithsonian's top job; the man-carrying Aerodrome survived after being rebuilt and tested by Curtiss and was converted back to Langley's original 1903 configuration by Smithsonian staff. It occupied a place of honor in the Smithsonian museum until 1948 when the Institution welcomed home the original 1903 Wright Flyer from the UK.
Afterward, the Aerodrome resided out of view of the public for many years at the Paul Garber Facility in Suitland, Maryland. Today
Canada is a country in the northern part of North America. Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering 9.98 million square kilometres, making it the world's second-largest country by total area. Canada's southern border with the United States is the world's longest bi-national land border, its capital is Ottawa, its three largest metropolitan areas are Toronto and Vancouver. As a whole, Canada is sparsely populated, the majority of its land area being dominated by forest and tundra, its population is urbanized, with over 80 percent of its inhabitants concentrated in large and medium-sized cities, many near the southern border. Canada's climate varies across its vast area, ranging from arctic weather in the north, to hot summers in the southern regions, with four distinct seasons. Various indigenous peoples have inhabited what is now Canada for thousands of years prior to European colonization. Beginning in the 16th century and French expeditions explored, settled, along the Atlantic coast.
As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces; this began an accretion of provinces and territories and a process of increasing autonomy from the United Kingdom. This widening autonomy was highlighted by the Statute of Westminster of 1931 and culminated in the Canada Act of 1982, which severed the vestiges of legal dependence on the British parliament. Canada is a parliamentary democracy and a constitutional monarchy in the Westminster tradition, with Elizabeth II as its queen and a prime minister who serves as the chair of the federal cabinet and head of government; the country is a realm within the Commonwealth of Nations, a member of the Francophonie and bilingual at the federal level. It ranks among the highest in international measurements of government transparency, civil liberties, quality of life, economic freedom, education.
It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many other countries. Canada's long and complex relationship with the United States has had a significant impact on its economy and culture. A developed country, Canada has the sixteenth-highest nominal per capita income globally as well as the twelfth-highest ranking in the Human Development Index, its advanced economy is the tenth-largest in the world, relying chiefly upon its abundant natural resources and well-developed international trade networks. Canada is part of several major international and intergovernmental institutions or groupings including the United Nations, the North Atlantic Treaty Organization, the G7, the Group of Ten, the G20, the North American Free Trade Agreement and the Asia-Pacific Economic Cooperation forum. While a variety of theories have been postulated for the etymological origins of Canada, the name is now accepted as coming from the St. Lawrence Iroquoian word kanata, meaning "village" or "settlement".
In 1535, indigenous inhabitants of the present-day Quebec City region used the word to direct French explorer Jacques Cartier to the village of Stadacona. Cartier used the word Canada to refer not only to that particular village but to the entire area subject to Donnacona. From the 16th to the early 18th century "Canada" referred to the part of New France that lay along the Saint Lawrence River. In 1791, the area became two British colonies called Upper Canada and Lower Canada collectively named the Canadas. Upon Confederation in 1867, Canada was adopted as the legal name for the new country at the London Conference, the word Dominion was conferred as the country's title. By the 1950s, the term Dominion of Canada was no longer used by the United Kingdom, which considered Canada a "Realm of the Commonwealth"; the government of Louis St. Laurent ended the practice of using'Dominion' in the Statutes of Canada in 1951. In 1982, the passage of the Canada Act, bringing the Constitution of Canada under Canadian control, referred only to Canada, that year the name of the national holiday was changed from Dominion Day to Canada Day.
The term Dominion was used to distinguish the federal government from the provinces, though after the Second World War the term federal had replaced dominion. Indigenous peoples in present-day Canada include the First Nations, Métis, the last being a mixed-blood people who originated in the mid-17th century when First Nations and Inuit people married European settlers; the term "Aboriginal" as a collective noun is a specific term of art used in some legal documents, including the Constitution Act 1982. The first inhabitants of North America are hypothesized to have migrated from Siberia by way of the Bering land bridge and arrived at least 14,000 years ago; the Paleo-Indian archeological sites at Old Crow Flats and Bluefish Caves are two of the oldest sites of human habitation in Canada. The characteristics of Canadian indigenous societies included permanent settlements, complex societal hierarchies, trading networks; some of these cultures had collapsed by the time European explorers arrived in the late 15th and early 16th centuries and have only been discovered through archeological investigations.
The indigenous population at the time of the first European settlements is estimated to have been between 200,000
The Smithsonian Institution, founded on August 10, 1846 "for the increase and diffusion of knowledge," is a group of museums and research centers administered by the Government of the United States. The institution is named after British scientist James Smithson. Organized as the "United States National Museum," that name ceased to exist as an administrative entity in 1967. Termed "the nation's attic" for its eclectic holdings of 154 million items, the Institution's nineteen museums, nine research centers, zoo include historical and architectural landmarks located in the District of Columbia. Additional facilities are located in Arizona, Massachusetts, New York City, Texas and Panama. More than 200 institutions and museums in 45 states, Puerto Rico, Panama are Smithsonian Affiliates; the Institution's thirty million annual visitors are admitted without charge. Its annual budget is around $1.2 billion with two-thirds coming from annual federal appropriations. Other funding comes from the Institution's endowment and corporate contributions, membership dues, earned retail and licensing revenue.
Institution publications include Air & Space magazines. The British scientist James Smithson left most of his wealth to his nephew Henry James Hungerford; when Hungerford died childless in 1835, the estate passed "to the United States of America, to found at Washington, under the name of the Smithsonian Institution, an Establishment for the increase & diffusion of knowledge among men", in accordance with Smithson's will. Congress accepted the legacy bequeathed to the nation, pledged the faith of the United States to the charitable trust on July 1, 1836; the American diplomat Richard Rush was dispatched to England by President Andrew Jackson to collect the bequest. Rush returned in August 1838 with 105 sacks containing 104,960 gold sovereigns. Once the money was in hand, eight years of Congressional haggling ensued over how to interpret Smithson's rather vague mandate "for the increase and diffusion of knowledge." The money was invested by the US Treasury in bonds issued by the state of Arkansas, which soon defaulted.
After heated debate, Massachusetts Representative John Quincy Adams persuaded Congress to restore the lost funds with interest and, despite designs on the money for other purposes, convinced his colleagues to preserve it for an institution of science and learning. On August 10, 1846, President James K. Polk signed the legislation that established the Smithsonian Institution as a trust instrumentality of the United States, to be administered by a Board of Regents and a Secretary of the Smithsonian. Though the Smithsonian's first Secretary, Joseph Henry, wanted the Institution to be a center for scientific research, it became the depository for various Washington and U. S. government collections. The United States Exploring Expedition by the U. S. Navy circumnavigated the globe between 1838 and 1842; the voyage amassed thousands of animal specimens, an herbarium of 50,000 plant specimens, diverse shells and minerals, tropical birds, jars of seawater, ethnographic artifacts from the South Pacific Ocean.
These specimens and artifacts became part of the Smithsonian collections, as did those collected by several military and civilian surveys of the American West, including the Mexican Boundary Survey and Pacific Railroad Surveys, which assembled many Native American artifacts and natural history specimens. In 1846, the regents developed a plan for weather observation; the Institution became a magnet for young scientists from 1857 to 1866, who formed a group called the Megatherium Club. The Smithsonian played a critical role as the U. S. partner institution in early bilateral scientific exchanges with the Academy of Sciences of Cuba. Construction began on the Smithsonian Institution Building in 1849. Designed by architect James Renwick Jr. its interiors were completed by general contractor Gilbert Cameron. The building opened in 1855; the Smithsonian's first expansion came with construction of the Arts and Industries Building in 1881. Congress had promised to build a new structure for the museum if the 1876 Philadelphia Centennial Exposition generated enough income.
It did, the building was designed by architects Adolf Cluss and Paul Schulze, based on original plans developed by Major General Montgomery C. Meigs of the United States Army Corps of Engineers, it opened in 1881. The National Zoological Park opened in 1889 to accommodate the Smithsonian's Department of Living Animals; the park was designed by landscape architect Frederick Law Olmsted. The National Museum of Natural History opened in June 1911 to accommodate the Smithsonian's United States National Museum, housed in the Castle and the Arts and Industries Building; this structure was designed by the D. C. architectural firm of Hornblower & Marshall. When Detroit philanthropist Charles Lang Freer donated his private collection to the Smithsonian and funds to build the museum to hold it, it was among the Smithsonian's first major donations from a private individual; the gallery opened in 1923. More than 40 years would pass before the next museum, the Museum of History and Technology, opened in 1964.
It was designed by the world-renowned firm of Mead & White. The Anacostia Community Museum, an "experimental store-front" museum created at the initiative of Smithsonian Secretary S. Dillon Ripley, opened in the Anacostia neighborhood of
James Edward Keeler
James Edward Keeler was an American astronomer. Keeler worked at Lick Observatory beginning in 1888, but left after being appointed director of the University of Pittsburgh's Allegheny Observatory in 1891, he returned to Lick Observatory as its director in 1898, but died not long after in 1900. His ashes were interred in a crypt at the base of the 31-inch Keeler Memorial telescope at the Allegheny Observatory. Along with George Hale, Keeler founded and edited the Astrophysical Journal, which remains a major journal of astronomy today, his parents were Anna Keeler. He had left a widow and two children. Keeler was the first to observe the gap in Saturn's rings now known as the Encke Gap, using the 36-inch refractor at Lick Observatory on 7 January 1888. After this feature had been named for Johann Encke, who had observed a much broader variation in the brightness of the A Ring, Keeler's contributions were brought to light; the second major gap in the A Ring, discovered by Voyager, was named the Keeler Gap in his honor.
In 1895, his spectroscopic study of the rings of Saturn revealed that different parts of the rings reflect light with different Doppler shifts, due to their different rates of orbit around Saturn. This was the first observational confirmation of the theory of James Clerk Maxwell that the rings are made up of countless small objects, each orbiting Saturn at its own rate; these observations were made with a spectrograph attached to the 13-inch Fitz-Clark refracting telescope at Allegheny Observatory. His observations with the Lick Crossley telescope helped establish the importance of large optical reflecting telescopes, expanded astronomers' understanding of nebulae. After his untimely death, his colleagues at Lick Observatory arranged for the publication of his photographs of nebulae and clusters in a special volume of the Lick Observatory publications. Keeler discovered two minor planets, the Koronis asteroid 452 Hamiltonia in 1899, the Mars-crosser asteroid A900 MA in 1900, which became a lost minor planet until its recovery 99 years later.
After the discovery of pulsars in 1967, optical images of the Crab Nebula taken by Keeler in 1899 were used to determine the proper motion of the Crab Pulsar. Keeler was awarded the Henry Draper Medal from the National Academy of Sciences in 1899. In 1900 he was elected president of the Astronomical Society of the Pacific. In 1880, Allegheny Observatory director Samuel Pierpont Langley, accompanied by Keeler and others, went on a scientific expedition to the summit of Mount Whitney; the purpose of the expedition was to study how the Sun's radiation was selectively absorbed by the Earth's atmosphere, comparing the results at high altitude with those found at lower levels. As a result of the expedition, a 14,240-ft. Peak near Mount Whitney was named the "Keeler Needle". In addition to the Keeler gap in Saturn's rings, the Martian crater Keeler, the lunar crater Keeler, as well as the asteroid 2261 Keeler, are named in his honor. Works by James Edward Keeler at Project Gutenberg Works by or about James Edward Keeler at Internet Archive Campbell, W. W..
"James Edward Keeler". Astrophysical Journal. 12: 239–253. Bibcode:1900ApJ....12..239C. doi:10.1086/140764. H. H. T.. "List of Fellows and Associates deceased during the past year". Monthly Notices of the Royal Astronomical Society. 61: 197–199. Bibcode:1901MNRAS..61..197.. Doi:10.1093/mnras/61.4.197. National Academy of Sciences Biographical Memoir
Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics and chemistry in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, stars, nebulae and comets. More all phenomena that originate outside Earth's atmosphere are within the purview of astronomy. A related but distinct subject is physical cosmology, the study of the Universe as a whole. Astronomy is one of the oldest of the natural sciences; the early civilizations in recorded history, such as the Babylonians, Indians, Nubians, Chinese and many ancient indigenous peoples of the Americas, performed methodical observations of the night sky. Astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, but professional astronomy is now considered to be synonymous with astrophysics. Professional astronomy is split into theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, analyzed using basic principles of physics.
Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain observational results and observations being used to confirm theoretical results. Astronomy is one of the few sciences in which amateurs still play an active role in the discovery and observation of transient events. Amateur astronomers have made and contributed to many important astronomical discoveries, such as finding new comets. Astronomy means "law of the stars". Astronomy should not be confused with astrology, the belief system which claims that human affairs are correlated with the positions of celestial objects. Although the two fields share a common origin, they are now distinct. Both of the terms "astronomy" and "astrophysics" may be used to refer to the same subject. Based on strict dictionary definitions, "astronomy" refers to "the study of objects and matter outside the Earth's atmosphere and of their physical and chemical properties," while "astrophysics" refers to the branch of astronomy dealing with "the behavior, physical properties, dynamic processes of celestial objects and phenomena."
In some cases, as in the introduction of the introductory textbook The Physical Universe by Frank Shu, "astronomy" may be used to describe the qualitative study of the subject, whereas "astrophysics" is used to describe the physics-oriented version of the subject. However, since most modern astronomical research deals with subjects related to physics, modern astronomy could be called astrophysics; some fields, such as astrometry, are purely astronomy rather than astrophysics. Various departments in which scientists carry out research on this subject may use "astronomy" and "astrophysics" depending on whether the department is affiliated with a physics department, many professional astronomers have physics rather than astronomy degrees; some titles of the leading scientific journals in this field include The Astronomical Journal, The Astrophysical Journal, Astronomy and Astrophysics. In early historic times, astronomy only consisted of the observation and predictions of the motions of objects visible to the naked eye.
In some locations, early cultures assembled massive artifacts that had some astronomical purpose. In addition to their ceremonial uses, these observatories could be employed to determine the seasons, an important factor in knowing when to plant crops and in understanding the length of the year. Before tools such as the telescope were invented, early study of the stars was conducted using the naked eye; as civilizations developed, most notably in Mesopotamia, Persia, China and Central America, astronomical observatories were assembled and ideas on the nature of the Universe began to develop. Most early astronomy consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, the nature of the Sun and the Earth in the Universe were explored philosophically; the Earth was believed to be the center of the Universe with the Sun, the Moon and the stars rotating around it. This is known as the geocentric model of the Ptolemaic system, named after Ptolemy.
A important early development was the beginning of mathematical and scientific astronomy, which began among the Babylonians, who laid the foundations for the astronomical traditions that developed in many other civilizations. The Babylonians discovered. Following the Babylonians, significant advances in astronomy were made in ancient Greece and the Hellenistic world. Greek astronomy is characterized from the start by seeking a rational, physical explanation for celestial phenomena. In the 3rd century BC, Aristarchus of Samos estimated the size and distance of the Moon and Sun, he proposed a model of the Solar System where the Earth and planets rotated around the Sun, now called the heliocentric model. In the 2nd century BC, Hipparchus discovered precession, calculated the size and distance of the Moon and inven
Sunspots are temporary phenomena on the Sun's photosphere that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection. Sunspots appear in pairs of opposite magnetic polarity, their number varies according to the 11-year solar cycle. Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but decay. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from 16 km to 160,000 km; the larger variety are visible from Earth without the aid of a telescope. They may travel at relative speeds, or proper motions, of a few hundred meters per second when they first emerge. Indicating intense magnetic activity, sunspots accompany secondary phenomena such as coronal loops and reconnection events. Most solar flares and coronal mass ejections originate in magnetically active regions around visible sunspot groupings. Similar phenomena indirectly observed on stars other than the Sun are called starspots, both light and dark spots have been measured.
The earliest extant report of sunspots dates back to the Chinese Book of Changes, c. 800 BC. The first clear mention of a sunspot in Western literature, around 300 BC, was by the ancient Greek scholar Theophrastus, student of Plato and Aristotle and successor to the latter; the earliest surviving record of deliberate sunspot observation dates from 364 BC, based on comments by Chinese astronomer Gan De in a star catalogue. By 28 BC, Chinese astronomers were recording sunspot observations in official imperial records. Sunspots were first observed telescopically in late 1610 by English astronomer Thomas Harriot and Frisian astronomers Johannes and David Fabricius, who published a description in June 1611. Although they are at temperatures of 3,000–4,500 K, the contrast with the surrounding material at about 5,780 K leaves sunspots visible as dark spots; this is because the luminance of a heated black body at these temperatures varies with temperature—considerably more so than the variation in the total black-body radiation at all wavelengths.
Isolated from the surrounding photosphere a sunspot would be brighter than the Moon. Sunspots have two parts: the central umbra, the darkest part, where the magnetic field is vertical and the surrounding penumbra, lighter, where the magnetic field is more inclined. Any given appearance of a sunspot may last anywhere from a few days to a few months, though groups of sunspots and their active regions tend to last weeks or months, but all do decay and disappear. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from 16 km to 160,000 km. Although the details of sunspot generation are still a matter of research, it appears that sunspots are the visible counterparts of magnetic flux tubes in the Sun's convective zone that get "wound up" by differential rotation. If the stress on the tubes reaches a certain limit, they puncture the Sun's surface. Convection is inhibited at the puncture points; the Wilson effect implies. Observations using the Zeeman effect show that prototypical sunspots come in pairs with opposite magnetic polarity.
From cycle to cycle, the polarities of leading and trailing sunspots change from north/south to south/north and back. Sunspots appear in groups. Magnetic pressure should tend to remove field concentrations, causing the sunspots to disperse, but sunspot lifetimes are measured in days to weeks. In 2001, observations from the Solar and Heliospheric Observatory using sound waves traveling below the photosphere were used to develop a three-dimensional image of the internal structure below sunspots. Sunspot activity cycles are with some variation in length. Over the solar cycle, sunspot populations rise and fall more slowly; the point of highest sunspot activity during a cycle is known as solar maximum, the point of lowest activity as solar minimum. This period is observed in most other solar activity and is linked to a variation in the solar magnetic field that changes polarity with this period. Early in the cycle, sunspots appear in the higher latitudes and move towards the equator as the cycle approaches maximum, following Spörer's law.
Spots from two adjacent cycles can co-exist for some time. Spots from adjacent cycles can be distinguished by direction of their magnetic field; the Wolf number sunspot index counts the average number of sunspots and groups of sunspots during specific intervals. The 11-year solar cycles are numbered sequentially, starting with the observations made in the 1750s. George Ellery Hale first linked magnetic fields and sunspots in 1908. Hale suggested that the sunspot cycle period is 22 years, covering two periods of increased and decreased sunspot numbers, accompanied by polar reversals of the solar magnetic dipole field. Horace W. Babcock proposed a qualitative model for the dynamics of the solar outer layers; the Babcock Model explains that magnetic fields cause the behavior described by Spörer's law, as well as other effects, whi
Public transport timetable
A public transport timetable is a document setting out information on service times, to assist passengers with planning a trip. The timetable will list the times when a service is scheduled to arrive at and depart from specified locations, it may show all movements at a particular location or all movements on a particular route or for a particular stop. Traditionally this information was provided in printed form, for example as a poster, it is now often available in a variety of electronic formats. In the 2000s public transport route planners / intermodal journey planners have proliferated and offer traveller the convenience that the computer program looks at all timetables so the traveller doesn't need to. A "timetable" may refer to the same information in abstract form, not published, e.g. "A new timetable has been introduced". The first compilation of railway timetables in the United Kingdom was produced in 1839 by George Bradshaw. Greater speeds and the need for more accurate timings led to the introduction of standard railway time in Great Western Railway timetables in 1840, when all their trains were scheduled to "London time", i.e. Greenwich Mean Time, which replaced solar time.
Until railway time was introduced, local times for London, Birmingham and Manchester could differ by as much as 16 to 20 minutes. The European Rail Timetable, a compendium of the schedules of major European railway services, has been in publication since 1873, and for most of its history, it was published by Thomas Cook & Son and included Thomas Cook or Cook's in its title. Although Thomas Cook Group plc ceased publication in 2013, the Thomas Cook European Rail Timetable was revived by a new company in early 2014 as the European Rail Timetable. From 1981 to 2010, Cook produced a similar bi-monthly Overseas volume covering the rest of the world, some of that content was moved into the European Timetable in 2011. A timetable can be produced dynamically, on request, for a particular journey on a particular day around a particular time, or in a timetable that gives an overview of all services in a particular category and is valid for a specified period; the latter could take the form of a book, billboard, or a computer file, makes it much easier to find out, for example, whether a transport service at a particular time is offered every day at that time, if not, on which days.
Many timetables comprise tables with services shown in columns, stations or stops on the rows of the table. There will be separate tables for each direction of travel, separate tables for weekdays and Sundays; the times shown against each station or stop will be the departure time, except for the last stop of the service which will be the arrival time. The left hand column will list the stations in route order, the other columns are arranged from left to right in chronological order. If the service is scheduled to wait, both arrival and departure times might be shown on consecutive rows. If a slow service is overtaken by a fast service, the slow service will occupy more than one column, to keep the times in order. There may be additional rows showing connecting services. In most parts of the world times are shown using the 24-hour clock. If services run at the same minutes past each hour for part of the day, the legend "and at the same minutes past each hour" or similar wording may be shown instead of individual timings.
Other information may be shown at the tops of the columns, such as day of operation, validity of tickets for each service, whether seat reservations are required, the type of vehicle used, the availability of on-board facilities such as refreshments, availability of classes, a service number. Timetables with services arranged in rows of tables and stops or stations in columns are less common but otherwise similar to timetables with services in columns; some timetables at railway stations and bus stops, list the times that services depart from that location, sometimes with other information such as destinations and stopping conditions. Again, there may be separate lists for different days of the week. There may be a combined chronological list. In parts of mainland Europe train departures are listed on a yellow poster, arrivals on a white poster; these posters are placed at entrances on platforms. Dynamic electronic displays in stations may be at a central place and list the next few departures for each line, or all departures in the next hour.
Displays on platforms just show the next departure from that platform. Timetables may be printed as books, folded or plain cards or paper, posters, or hand-written on posters or blackboards, shown on back-lit displays, or published on-line or as SMS or text messages. With the development of the internet and electronic systems, conventional thick paper timetables are being replaced by website searching or CD-ROM style timetables, the publication of comprehensive printed timetables is decreasing. Transport schedule data itself is being made available to the public digitally, as specified in the General Transit Feed Specification format. In many modern public transport systems, timet