Editing Morse code (section)

===Pre-Morse telegraphs and codes===
[[File:Single needle telegraph (Rankin Kennedy, Electrical Installations, Vol V, 1903).jpg|thumb|200px|left|Single needle telegraph instrument]]
Early in the nineteenth century, European experimenters made progress with electrical signaling systems, using a variety of techniques including [[static electricity]] and electricity from [[Voltaic pile]]s producing [[Electrochemistry|electrochemical]] and [[electromagnetism|electromagnetic]] changes. These experimental designs were precursors to practical telegraphic applications.<ref name=Fahie-1884/>
[[File:Telegraph key and sounder, L.C.T. (L. C. Tillotson) and Co., 8 Dey Street, NY - Bennington Museum - Bennington, VT - DSC08636.JPG|thumb|250px|right|[[Telegraph key]] and [[Telegraph sounder|sounder]]; the signal is "on" when the knob is pressed, and "off" when it is released, length and timing of the ''dits'' and ''dahs'' are entirely controlled by the [[telegraphist]]]]
Following the discovery of [[electromagnetism]] by [[Hans Christian Ørsted]] in 1820 and the invention of the [[electromagnet]] by [[William Sturgeon]] in 1824, there were developments in [[Electrical telegraph|electromagnetic telegraphy]] in Europe and America. Pulses of [[electric current]] were sent along wires to control an electromagnet in the receiving instrument. Many of the earliest telegraph systems used a single-needle system which gave a very simple and robust instrument. However, it was slow, as the receiving operator had to alternate between looking at the needle and writing down the message. In Morse code, a deflection of the needle to the left corresponded to a ''dit'' and a deflection to the right to a ''dah''.<ref name=UK-Engr-1919-1938/> The needle clicked each time it moved to the right or left. By making the two clicks sound different (by installing one ivory and one metal stop), transmissions on the single needle device became audible as well as visible, which led in turn to the ''Double Plate [[Telegraph sounder|Sounder]]'' System.<ref name=Freebody-1959/>

[[William Fothergill Cooke|William Cooke]] and [[Charles Wheatstone]] in [[United Kingdom|Britain]] developed an electrical telegraph that used electromagnets in its receivers. They obtained an English patent in June&nbsp;1837 and demonstrated it on the London and Birmingham Railway, making it the first commercial telegraph. [[Carl Friedrich Gauss]] and [[Wilhelm Eduard Weber]] (1833) as well as [[Carl August von Steinheil]] (1837) used codes with varying word lengths for their telegraph systems.<ref name=Smithsonian-Report-1879/> In 1841, Cooke and Wheatstone built a telegraph that printed the letters from a wheel of typefaces struck by a hammer.<ref name=Burns-2004/>{{rp|page=79}}

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