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 that 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 occurred 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 public acceptance and use of the telegraph.
Inventors
The telegraph arose from a collaboration between William Fothergill Cooke and Charles Wheatstone, best known to schoolchildren from the eponymous Wheatstone bridge. Their collaboration was not a happy one because their objectives differed. 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, and he intended to publish his results and allow others to freely make use of them.Bowers, page 119 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.Bowler & Morus, pages 403–404
Cooke had 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.Shaffner, page 185
History
In January 1837, Cooke proposed to the directors of the Liverpool and Manchester Railway a design for a 60-code mechanical telegraph.Schaffner, p. 190 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.Bowers, page 123 However, the railway decided to use instead a pneumatic telegraph equipped with whistles.Burns, page 72 Soon after this Cooke went into partnership with Wheatstone.Bowers, pages 124–125
In May 1837 Cooke and Wheatstone patented a telegraph system that 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.The telegraphic age dawns BT Group Connected Earth Online Museum. Accessed December 2010, 10 Feb 2013 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.Bowers, page 129
Cooke and Wheatstone had their first commercial success with a telegraph installed in 1838 on the Great Western Railway over the from Paddington station to West Drayton. Indeed, this was the first commercial telegraph in the world.Huurdeman, page 67 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.Mercer, page 7 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.Kieve, pages 32-33
When the line was extended to Slough in 1843, a one-needle, two-wire system was installed.Huurdeman, page 69 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,Kieve, page 32 and which rapidly became the most common method.Duffy, page 5 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, establishing a public telegraph service for the first time.Kieve, pages 31-32 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.Kieve, page 33
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.Beauchamp, page 35 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.Kieve pages 30-31 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.Kieve, pages 37–38 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.Mercer, page 8 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.Huurdeman, pages 67–69
The Cooke and Wheatstone telegraph was largely confined to the United Kingdom and the British Empire. However, it was also used in Spain for a time.Huurdeman, p. 107 After nationalisation of the telegraph sector in the UK, the Post Office slowly replaced the diverse systems it had inherited, including the Cooke and Wheatstone telegraph, with the Morse telegraph system.Kieve, p. 176
Tawell arrest
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.Burns, pages 78–79
Railway block working 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 Way 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.Kieve, pages 33-34 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.Duffy, page 378
Operation
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.