The Cooke and Wheatstone telegraph was an early electrical telegraph system dating from the 1830s invented by English inventor William Fothergill Cooke and English scientist Charles Wheatstone. It was a form of needle telegraph, and the first telegraph system to be put into commercial service. The receiver consisted of a number of needles which could be moved by electromagnetic coils to point to letters on a board. This feature was liked by early users who were unwilling to learn codes, and employers who did not want to invest in staff training.
In later systems the letter board was dispensed with, and the code was read directly from the movement of the needles. This came about because the number of needles was reduced, leading to more complex codes. The change was motivated by the economic need to reduce the number of telegraph wires used, which was related to the number of needles. The change became more urgent as the insulation of some of the early installations deteriorated, causing some of the original wires to be unusable. Cooke and Wheatstone's most successful system was eventually a one-needle system that continued in service into the 1930s.
Cooke and Wheatstone's telegraph played a part in the apprehension of the murderer John Tawell. Once it was known that Tawell had boarded a train to London, the telegraph was used to signal ahead to the terminus at Paddington and have him arrested there. The novelty of this use of the telegraph in crime-fighting generated a great deal of publicity and led to increased acceptance and use of the telegraph by the public.
The telegraph arose from a collaboration between William Fothergill Cooke and Charles Wheatstone, best known to schoolchildren from the eponymous Wheatstone bridge. This was not a happy collaboration due to the differing objectives of the two men. Cooke was an inventor and entrepreneur who wished to patent and commercially exploit his inventions. Wheatstone, on the other hand, was an academic with no interest in commercial ventures. He intended to publish his results and allow others to freely make use of them. This difference in outlook eventually led to a bitter dispute between the two men over claims to priority for the invention. Their differences were taken to arbitration with Marc Isambard Brunel acting for Cooke and John Frederic Daniell acting for Wheatstone. Cooke eventually bought out Wheatstone's interest in exchange for royalties.
Cooke had some ideas for building a telegraph prior to his partnership with Wheatstone and had consulted scientist Michael Faraday for expert advice. In 1836, Cooke built both an experimental electrometer system and a mechanical telegraph involving a clockwork mechanism with an electromagnetic detent. However, much of the scientific knowledge for the model actually put into practice came from Wheatstone. Cooke's earlier ideas were largely abandoned.
In January 1837 Cooke proposed a design for a 60-code telegraph to the directors of the Liverpool and Manchester Railway. This was too complicated for their purposes; the immediate need was for a simple signal communication between the Liverpool station and a rope-haulage engine house at the top of a steep incline through a long tunnel outside the station. Rope-haulage into main stations was common at this time to avoid noise and pollution, and in this case the gradient was too steep for the locomotive to ascend unaided. All that was required were a few simple signals such as an indication to the engine house to start hauling. Cooke was requested to build a simpler version with fewer codes, which he did by the end of April 1837. However, the railway decided to use instead a pneumatic telegraph equipped with whistles. Soon after this Cooke went into partnership with Wheatstone.
In May 1837 Cooke and Wheatstone patented a telegraph system which used a number of needles on a board that could be moved to point to letters of the alphabet. The patent recommended a five-needle system, but any number of needles could be used depending on the number of characters it was required to code. A four-needle system was installed between Euston and Camden Town in London on a rail line being constructed by Robert Stephenson between London and Birmingham. It was successfully demonstrated on 25 July 1837. This was a similar application to the Liverpool project. The carriages were detached at Camden Town and travelled under gravity into Euston. A system was needed to signal to an engine house at Camden Town to start hauling the carriages back up the incline to the waiting locomotive. As at Liverpool, the electric telegraph was in the end rejected in favour of a pneumatic system with whistles.
Cooke and Wheatstone had their first commercial success with a telegraph installed on the Great Western Railway over the 13 miles (21 km) from Paddington station to West Drayton in 1838. Indeed, this was the first commercial telegraph in the world. This was a five-needle, six-wire system. The cables were originally installed underground in a steel conduit. However, the cables soon began to fail as a result of deteriorating insulation. As an interim measure, a two-needle system was used with three of the remaining working underground wires, which despite using only two needles had a greater number of codes. Since the new code had to be learned, not just read off the display, this was the first time in telegraph history that skilled telegraph operators were required.
When the line was extended to Slough in 1843, a one-needle, two-wire system was installed. Cooke also changed from running the cables in buried lead pipes to the less expensive and easier to maintain system of suspending uninsulated wires on poles from ceramic insulators, a system which he patented, and which rapidly became the commonest method. This extension was done at Cooke's own expense, as the railway company was unwilling to finance a system it still considered experimental. Up to this point, the Great Western had insisted on exclusive use and refused Cooke permission to open public telegraph offices. Cooke's new agreement gave the railway free use of the system in exchange for Cooke's right to open public offices, for the first time establishing a public telegraph service. A flat rate was charged (unlike all later telegraph services which charged per word) of one shilling, but many people paid this just to see the strange equipment.
From this point on, the use of the electric telegraph started to grow on the new railways being built from London. The London and Blackwall Railway (another rope-hauled application) was equipped with the Cooke and Wheatstone telegraph when it opened in 1840, and many others followed. The distance involved on the Blackwall Railway (four miles) was too far for steam signalling and the engineer, Robert Stephenson, strongly supported the electric solution. In February 1845, an 88-mile line from Nine Elms to Gosport was completed along the London and South Western Railway, far longer than any other line up to that time. The Admiralty paid half the capital cost and £1,500 per annum for a private two-needle telegraph on this line to connect it to its base in Portsmouth, finally replacing the optical telegraph. In September 1845 the financier John Lewis Ricardo and Cooke formed the Electric Telegraph Company. This company bought out the Cooke and Wheatstone patents and solidly established the telegraph business. In 1869 the company was nationalised and became part of the General Post Office. The one-needle telegraph proved highly successful on British railways, and 15,000 sets were still in use at the end of the nineteenth century. Some remained in service in the 1930s.
Murder suspect John Tawell was apprehended following the use of a needle telegraph message from Slough to Paddington on 1 January 1845. This is thought to be the first use of the telegraph to catch a murderer. The message was:
A MURDER HAS GUST BEEN COMMITTED AT SALT HILL AND THE SUSPECTED MURDERER WAS SEEN TO TAKE A FIRST CLASS TICKET TO LONDON BY THE TRAIN WHICH LEFT SLOUGH AT 742 PM HE IS IN THE GARB OF A KWAKER WITH A GREAT COAT ON WHICH REACHES NEARLY DOWN TO HIS FEET HE IS IN THE LAST COMPARTMENT OF THE SECOND CLASS COMPARTMENT
The Cooke and Wheatstone system did not support punctuation, lower case, or some letters. Even the two-needle system omitted the letters J, Q, and Z; hence the misspellings of 'just' and 'Quaker'. This caused some difficulty for the receiving operator at Paddington who repeatedly requested a resend after receiving K-W-A which he assumed was a mistake. This continued until a small boy suggested the sending operator be allowed to complete the word, after which it was understood. After arriving, Tawell was followed to a nearby coffee shop by a detective and arrested there. Newspaper coverage of this incident gave a great deal of publicity to the electric telegraph and brought it firmly into public view.
The widely publicised arrest of Tawell was one of two events which brought the telegraph to greater public attention and led to its widespread use beyond railway signalling. The other event was the announcement by telegraph of the birth of Alfred Ernest Albert, second son of Queen Victoria. The news was published in The Times at the unprecedented speed of 40 minutes after the announcement.
The signalling block system is a train safety system that divides the track into blocks and uses signals to prevent another train entering a block until a train already in the block has left. The system was proposed by Cooke in 1842 in Telegraphic Railways or the Single Line as a safer way of working on single lines. Previously, separation of trains had relied on strict timetabling only, which was unable to allow for unforeseen events. The first use of block working was probably in 1839 when George Stephenson had a Cooke and Wheatstone telegraph installed in the Clay Cross Tunnel of the North Midland Railway. Instruments specific to block working were installed in 1841. Block working became the norm and remains so to the present day, except that modern technology has allowed fixed blocks to be replaced with moving blocks on the busiest railways.
The Cooke and Wheatstone telegraph consisted of a number of magnetic needles which could be made to turn a short distance either clockwise or anti-clockwise by electromagnetic induction from an energising winding. The direction of movement was determined by the direction of the current in the telegraph wires. The board was marked with a diamond shaped grid with a letter at each grid intersection, and so arranged that when two needles were energised they would point to a specific letter.
The number of wires required by the Cooke and Wheatstone system is equal to the number of needles used. The number of needles determines the number of characters that can be encoded. Cooke and Wheatstone's patent recommends five needles, and this was the number on their early demonstration models. The number of codes that can be obtained from 2, 3, 4, 5, 6 ... needles is 2, 6, 12, 20, 30 ... respectively.
At the sending end there were two rows of buttons, a pair of buttons for each coil in each row. The operator selected one button from each row. This connected two of the coils to the positive and negative ends of the battery respectively. The other ends of the coils were connected to the telegraph wires and thence to one end of the coils at the receiving station. The other end of the receiving coils, while in receive mode, were all commoned together. Thus the current flowed through the same two coils at both ends and energised the same two needles. With this system the needles were always energised in pairs and always rotated in opposite directions.
The five-needle telegraph with twenty possible needle positions was six codes short of being able to encode the complete alphabet. The letters omitted were C, J, Q, U, X and Z. A great selling point of this telegraph was that it was simple to use and required little operator training. There is no code to learn, as the letter being sent was visibly displayed to both the sending and receiving operator.
The Paddington to West Drayton telegraph originally used six wires rather than five, although it was a five-needle system. The sixth wire was to provide a common return so that the needles could be operated independently, thus giving the possibility of more available codes. Using these codes, however, would have required more extensive operator training since the display could not be read on sight from the grid as the simple alphabetic codes were. Telegraph systems were later to use earth return to avoid the need for a return wire, but this principle was not established at the time of Cooke and Wheatstone's telegraph. The economic need to reduce the number of wires in the end proved a stronger incentive than simplicity of use and led Cooke and Wheatstone to develop the two-needle telegraph.
The two-needle telegraph required three wires, one for each needle and a common return. The coding was somewhat different from the five-needle telegraph and needed to be learned, rather than read from a display. The needles could move to the left or right either one, two, or three times in quick succession, or a single time in both directions in quick succession. Either needle, or both together, could be moved. This gave a total of 24 codes, one of which was taken up by the stop code. Thus, three letters were omitted: J, Q and Z, which were substituted with G, K and S respectively.
Originally, the telegraph was fitted with a bell that rung when another operator wanted attention. This proved so annoying that it was removed. It was found that the clicking of the needle against its endstop was sufficient to draw attention.
This system was developed to replace the failing multi-wire telegraph on the Paddington to West Drayton line. It required only two wires, but a more complex code and slower transmission speed. Whereas the two-needle system needed a three-unit code (that is, up to three movements of the needles to represent each letter), the one-needle system used a four-unit code, but had enough codes to encode the entire alphabet. Like the preceding two-needle system, the code units consisted of rapid deflections of the needle to either left or right in quick succession. The needle struck a post when it moved causing it to ring. Different tones were provided for the left and right movements so that the operator could hear which direction the needle had moved without looking at it.
The codes were refined and adapted as they were used. By 1867 numerals had been added to the five-needle code. This was achieved through the provision of a sixth wire for common return making it possible to move just a single needle. With the original five wires it was only possible to move the needles in pairs and always in opposite directions since there was no common wire provided. Many more codes are theoretically possible with common return signalling, but not all of them can conveniently be used with a grid indication display. The numerals were worked in by marking them around the edge of the diamond grid. Needles 1 through 5 when energised to the right pointed to numerals 1 through 5 respectively, and to the left numerals 6 through 9 and 0 respectively. Two additional buttons were provided on the telegraph sets to enable the common return to be connected to either the positive or negative terminal of the battery according to the direction it was desired to move the needle.
Also by 1867, codes for Q () and Z () were added to the one-needle code, but not, apparently, for J. However, codes for Q (), Z (), and J () are marked on the plates of later needle telegraphs, together with six-unit codes for number shift () and letter shift (). Numerous compound codes were added for operator controls such as wait and repeat. These compounds are similar to the prosigns found in Morse code where the two characters are run together without a character gap. The two-needle number shift and letter shift codes are also compounds, which is the reason they have been written with an overbar.
The codes used for the four-needle telegraph are not known, and none of the equipment has survived. It is not even known which letters were assigned to the twelve possible codes.
The British and Irish Magnetic Telegraph Company (Magnetic Telegraph Company or just Magnetic for short) was the principal competitor to the Electric Telegraph Company (the Electric) in Britain. Between them, they dominated the market until the telegraph was nationalised in the United Kingdom in 1870.
The Magnetic's telegraph system differed from other companies. They favoured underground cables rather than wires suspended on poles. Their telegraph transmitters did not use batteries, instead the operator generated the necessary power electromagnetically. The Magnetic laid the first submarine telegraph cable to Ireland and developed an extensive telegraph network on that island.
The company was amongst the first to employ women as telegraph operators.Charles Wheatstone
Sir Charles Wheatstone FRS HFRSE DCL LLD (6 February 1802 – 19 October 1875), was an English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope (a device for displaying three-dimensional images), and the Playfair cipher (an encryption technique). However, Wheatstone is best known for his contributions in the development of the Wheatstone bridge, originally invented by Samuel Hunter Christie, which is used to measure an unknown electrical resistance, and as a major figure in the development of telegraphy.Electric Telegraph Company
The Electric Telegraph Company (ETC) was a British telegraph company founded in 1846 by William Fothergill Cooke and John Ricardo. It was the world's first public telegraph company. The equipment used was the Cooke and Wheatstone telegraph, an electrical telegraph developed a few years earlier in collaboration with Charles Wheatstone. The system had been taken up by several railway companies for signalling purposes, but in forming the company Cooke intended to open up the technology to the public at large.
The ETC had a monopoly of electrical telegraphy until the formation of the Magnetic Telegraph Company (commonly called the Magnetic) who used a different system which did not infringe the ETC's patents. The Magnetic became the chief rival of the ETC and the two of them dominated the market even after further companies entered the field.
The ETC was heavily involved in laying submarine telegraph cables, including lines to the Netherlands, Ireland, the Channel Islands, and the Isle of Man. They operated the world's first specialised cable-laying ship, the Monarch. A private line was laid for Queen Victoria on the Isle of Wight. The company was nationalised in 1870 along with other British telegraph companies, and their assets were taken over by the General Post Office.Electrical telegraph
An electrical telegraph is a telegraph that uses coded electrical signals to convey information via dedicated electrical wiring. Electrical telegraphy dates from the early 1800s, and is distinct from the later electrical telephony, which uses the analogue magnitude of electrical signals to convey information.
The electrical telegraph, or more commonly just telegraph, superseded visual semaphore telegraph and was the first form of electrical telecommunication. In a matter of decades after their creation in the 1830s, electrical telegraph networks permitted people and commerce to transmit messages across both continents and oceans almost instantly, with widespread social and economic impacts.Electrical telegraphy in the United Kingdom
Electrical telegraphy in the United Kingdom led the world in the first half of the nineteenth century. Electrical telegraphy is telegraphy over conducting wires. It is distinct from the optical telegraphy that preceded it and the radiotelegraphy that followed it. Francis Ronalds first demonstrated a working telegraph over a substantial distance in 1816, but was unable to put it into use. William Fothergill Cooke, starting in 1836, developed the first commercial telegraph put into operation with the scientific assistance of Charles Wheatstone, the battery invented by John Frederic Daniell, and the relay invented by Edward Davy.
In 1846 the Electric Telegraph Company (the Electric), the world's first telegraph company, was formed by Cooke and financier John Lewis Ricardo. The company initially supplied telegraph systems to railway companies, but soon branched out into other businesses and slowly built a network that could be used by the general public. Many competing companies arose; chief amongst them was the Magnetic Telegraph Company (the Magnetic) formed in 1850. The Magnetic used the telegraph invented by William Thomas Henley which did not require batteries. The Electric and Magnetic companies soon formed a cartel to control the market. The London District Telegraph Company (the District), an offshoot of the Magnetic, provided a cheap telegram service in London with a rooftop to rooftop network. The United Kingdom Telegraph Company did not launch until 1860 and struggled to compete with the big two. Most telegraph companies were unprofitable except for the Electric and Magnetic.
Submarine telegraph cables were made possible by the introduction of gutta-percha in 1843 by Scottish military surgeon William Montgomerie while stationed in Singapore. Gutta-percha was ideal for making underwater cables in an age before synthetic plastics. The Submarine Telegraph Company laid the world's first international submarine cable in 1851 when they connected England with France. Cable cores were made by the Gutta Percha Company who had a monopoly on the supply of the material until about 1863. Completed cables were made by wire rope manufacturers who armoured the cables. The Gutta Percha Company merged with one such wire rope manufacturer, R.S. Newall and Company, to form the Telegraph Construction and Maintenance Company (Telcon) in 1864 at the instigation of John Pender. Pender was the leading entrepreneur responsible for constructing a worldwide telegraph network. The transatlantic telegraph cable was laid by his Atlantic Telegraph Company in 1866 after several failures. Many more Pender companies were formed to lay various cables connecting Britain with its colonies in India and then on to the Far East and Australia. Once the cables were laid, these disparate companies were merged into the Eastern Telegraph Company, first established in 1872. The company was absorbed into Cable & Wireless Ltd in 1934.
The inland telegraph companies were nationalised in 1870 and were then run as part of the General Post Office. Companies operating international submarine cables were left independent. A major mistake made during nationalisation was that the estimated costs failed to take into account the cost of purchasing railway company wayleaves, or even that it would be necessary to do so. The final bill far exceeded the original estimate. The telegraph was never profitable under nationalisation because of government policies. Prices were held low to make it affordable to as many people as possible and the telegraph was extended to every post office issuing money orders, whether or not that office generated enough telegraph business to be profitable. Telegraph usage increased enormously under the Post Office, but it was never as cheap as the postal service and growing competition from the telephone started to eat into its market share.
The telegraph was an important resource in both World War I and World War II which somewhat delayed its decline. Decline was also countered with the introduction of special greetings telegrams (birthdays etc.) in 1935 which proved highly popular. Even so, by 1970 telegram usage had fallen to its lowest ever total under nationalisation. Repeated price rises to control the deficit drove usage down even further. Post Office Telecommunications was separated from the Post Office as British Telecom in 1981 to enable it to be privatised (which occurred in 1984). In 1982 British Telecom ended its inland telegram service. International telegrams could be sent by telephone and were received by ordinary letter post. Some private wire use of telegraph continued after the end of the telegram service, and the telex system continued in use by an ever-diminishing group of private users. Most of these succumbed to alternatives on the internet in the 1990s.Foy-Breguet telegraph
The Foy-Breguet telegraph was an electrical telegraph of the needle telegraph type invented by Louis-François-Clement Breguet and Alphonse Foy in 1842. The system used two-needle instruments that presented a display using the same code as that on the optical telegraph of Claude Chappe. The Chappe telegraph was extensively used in France by the government, so this arrangement was appealing to them as it meant there was no need to retrain operators.List of British innovations and discoveries
The following is a list and timeline of innovations as well as inventions and discoveries that involved British people or the United Kingdom including predecessor states in the history of the formation of the United Kingdom. This list covers innovation and invention in the mechanical, electronic, and industrial fields, as well as medicine, military devices and theory, artistic and scientific discovery and innovation, and ideas in religion and ethics.
The scientific revolution in 17th century Europe stimulated innovation and discovery in Britain. Experimentation was considered central to innovation by groups such as the Royal Society, which was founded in 1660. The English patent system evolved from its medieval origins into a system that recognised intellectual property; this encouraged invention and spurred on the Industrial Revolution from the late 18th century. During the 19th century, innovation in Britain led to revolutionary changes in manufacturing, the development of factory systems, and growth of transportation by railway and steam ship that spread around the world. In the 20th century, Britain's rate of innovation, measured by patents registered, slowed in comparison to other leading economies. Nonetheless, science and technology in Britain continued to develop rapidly in absolute terms.Liverpool and Manchester Railway
The Liverpool and Manchester Railway (L&MR) was a railway opened on 15 September 1830 between the Lancashire towns of Liverpool and Manchester in England. It was the first railway to rely exclusively on locomotives driven by steam power, with no horse-drawn traffic permitted at any time; the first to be entirely double track throughout its length; the first to have a signalling system; the first to be fully timetabled; and the first to carry mail. John B. Jervis of the Delaware and Hudson Railway some years later wrote: "It must be regarded ... as opening the epoch of railways which has revolutionised the social and commercial intercourse of the civilized world".Trains were hauled by company steam locomotives between the two towns, though private wagons and carriages were allowed. Cable haulage of freight trains was down the steeply-graded 1.26-mile (2.03 km) Wapping Tunnel to Liverpool Docks from Edge Hill junction. The railway was primarily built to provide faster transport of raw materials, finished goods and passengers between the Port of Liverpool and mills in Manchester and surrounding towns.
The railway was a financial success, paying investors an average annual dividend of 9.5% over the 15 years of its independent existence: a level of profitability that would never again be attained by a British railway company. In 1845 the railway was absorbed by its principal business partner, the Grand Junction Railway (GJR), which in turn amalgamated the following year with the London and Birmingham Railway and the Manchester and Birmingham Railway to form the London and North Western Railway.London and Blackwall Railway
Originally called the Commercial Railway, the London and Blackwall Railway (L&BR) in east London, England, ran from Minories to Blackwall via Stepney, with a branch line to the Isle of Dogs, connecting central London to many of London's docks. It was operational from 1840 until 1926 (for passengers) and 1968 (for goods), closing after the decline of inner London's docks. Much of its infrastructure was reused as part of the Docklands Light Railway. The L&BR was leased by the Great Eastern Railway in 1866, but remained independent until absorbed into the London and North Eastern Railway at the 1923 Grouping.Needle telegraph
A needle telegraph is an electrical telegraph that uses indicating needles moved electromagnetically as its means of displaying messages. It is one of the two main types of electromagnetic telegraph, the other being the armature system as exemplified by the telegraph of Samuel Morse in the United States. The principal needle system was the Cooke and Wheatstone telegraph, a system widely used in Britain and the British Empire in the 19th and early-20th centuries. However, the earliest needle telegraph was a binary coded multi-wire, multi-needle system invented by Pavel Schilling and demonstrated in St. Petersburg in 1832. Charles Wheatstone may have demonstrated one of Schilling's instruments in 1835 (that is, prior to his collaboration with Cooke to build a telegraph). Cooke definitely saw Schilling's needle instrument at a lecture of Georg Wilhelm Muncke in Heidelberg. It was this lecture that inspired Cooke to attempt building a telegraph, although he did not use needle instruments until Wheatstone came on board and suggested it.Other examples include;
Foy-Breguet telegraph, invented by Alphonse Foy and Louis-François-Clement Breguet in 1842, and used in France
Henley-Foster telegraph, invented in 1848 by William Thomas Henley and George Foster, and used by the British and Irish Magnetic Telegraph Company. This system did not require batteries.Signalling block system
Signalling block systems enable the safe and efficient operation of railways by preventing collisions between trains. The basic principle is that a route is broken up into a series of blocks, only one train may occupy a block at a time, and that the blocks are sized to allow a train to stop within them. This ensures that a train always has time to stop before reaching another train on the same line. A block system is referred to as the method of working in the UK, method of operation in the US and safeworking in Australia.
In most examples, a system of signals is used to control flow between the blocks. When a train enters a block, signals at both ends change to indicate that the block is occupied, typically using red lamps or indicator flags. When a train first enters a block, the rear of the same train has not yet left the previous block, so both blocks are marked as occupied. This ensures there is slightly less than one block length on either end of the train that is marked as occupied, so any other train approaching this section will have enough room to stop in time even if the first train stops dead on the tracks. The previously occupied block will only be marked unoccupied when the end of the train has entirely left it, leaving the entire block clear.
Block systems have the disadvantage that they limit the number of trains on a particular route to something smaller than the number of blocks. Since the route has a fixed length, increasing the number of trains requires more blocks, which means the blocks are shorter, which means the trains have to operate at lower speeds in order to safely stop. As a result, the number and size of blocks are strongly related to the route's overall route capacity and cannot be easily changed without changes to the signals all along the line.
Block systems are used to control trains between stations and yards, and not normally within the yards, where some other method will be used. Any block system is defined by its associated physical equipment and by the application of a relevant set of rules. Some systems involve the use of signals while others do not. Some systems are specifically designed for single track railways for which a danger exists of both head-on and rear-end collision, as opposed to double track, whose main danger is a rear-end collision.Submarine Telegraph Company
The Submarine Telegraph Company was formed by Jacob and John Watkins Brett to lay the first submarine telegraph cable across the English Channel. An unarmoured cable with gutta-percha insulation was laid in 1850. The recently introduced gutta-percha was the first thermoplastic material available to cable makers and was resistant to seawater. This first cable was a failure and was soon broken by a fishing boat.
A new cable was laid in 1851. This cable had multiple conductors and iron wire armouring. Telegraph communication with France was established for the first time in October of that year. This was the first undersea telegraph cable to be put in service anywhere in the world. The Submarine Telegraph Company continued to lay, and operate, more cables between England and the Continent until they were nationalised in 1890.Telegraphy
Telegraphy is the long-distance transmission of textual messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined and such systems are thus not true telegraphs.
The earliest true telegraph put into widespread use was the optical telegraph of Claude Chappe, invented in the late eighteenth century. The system was extensively used in France, and European countries controlled by France, during the Napoleonic era. The electric telegraph started to replace the optical telegraph in the mid-nineteenth century. It was first taken up in Britain in the form of the Cooke and Wheatstone telegraph, initally used mostly as an aid to railway signalling. This was quickly followed by a different system developed in the United States by Samuel Morse. The electric telegraph was slower to develop in France due to the established optical telegraph system, but an electrical telegraph was put into use with a code compatible with the Chappe optical telegraph. The Morse system was adopted as the international standard in 1865, using a modified Morse code developed in Germany.
The heliograph is a telegraph system using reflected sunlight for signalling. It was mainly used in areas where the electrical telegraph had not been established and generally uses the same code. The most extensive heliograph network established was in Arizona and New Mexico during the Apache Wars. The heliograph was standard military equipment as late as World War II. Wireless telegraphy developed in the early twentieth century. Wireless telegraphy became important for maritime use, and was a competitor to electrical telegraphy using submarine telegraph cables in international communications.
Telegrams became a popular means of sending messages once telegraph prices had fallen sufficiently. Traffic was became high enough to spur the development of automated systems – teleprinters and punched tape transmission. These systems led to new telegraph codes, starting with the Baudot code. However, telegrams were never able to compete with the letter post on price, and competition from the telephone, which removed their speed advantage, drove the telegraph into decline from 1920 onwards. The few remaining telegraph applications were largely taken over by alternatives on the internet towards the end of the twentieth century.Unbalanced line
This article is about the electrical transmission line. For the American football offensive line, see glossary of American football. For three-phase electric power lines carrying unbalanced currents see Three-phase electric power#Unbalanced loads.
In electrical engineering, an unbalanced line is a transmission line, often coaxial cable, whose conductors have unequal impedances with respect to ground; as opposed to a balanced line. Microstrip and single-wire lines are also unbalanced lines.Utility pole
A utility pole is a column or post used to support overhead power lines and various other public utilities, such as electrical cable, fiber optic cable, and related equipment such as transformers and street lights. It can be referred to as a transmission pole, telephone pole, telecommunication pole, power pole, hydro pole, telegraph pole, or telegraph post, depending on its application. A stobie pole is a multi-purpose pole made of two steel joists held apart by a slab of concrete in the middle, generally found in South Australia.
Electrical wires and cables are routed overhead on utility poles as an inexpensive way to keep them insulated from the ground and out of the way of people and vehicles. Utility poles can be made of wood, metal, concrete, or composites like fiberglass. They are used for two different types of power lines; subtransmission lines which carry higher voltage power between substations, and distribution lines which distribute lower voltage power to customers.
The first poles were used in 1843 by telegraph pioneer William Fothergill Cooke who used them on a line along the Great Western Railway. Utility poles were first used in the mid-19th century in America with telegraph systems, starting with Samuel Morse who attempted to bury a line between Baltimore and Washington, D.C., but moved it above ground when this system proved faulty. Today, underground distribution lines are increasingly used as an alternative to utility poles in residential neighborhoods, due to poles' perceived ugliness.Wheatstone
Wheatstone may refer to:
Cape Wheatstone, in Antarctica
Charles Wheatstone (1802–1875), a British scientist and inventor, eponymous for Wheatstone bridge
Cooke and Wheatstone Telegraph
Wheatstone, New Zealand, a locality in the Canterbury region
Wheatstone Glacier, in Antarctica
Wheatstone bridge, a measuring instrument in electricity
Wheatstone Corporation, an American manufacturing company