Editing Electrical telegraph (section)

===Oceanic telegraph cables===
[[File:1891 Telegraph Lines.jpg|right|thumb|upright=1.51|Major telegraph lines in 1891]]
{{Main|Transatlantic telegraph cable||Submarine communications cable}}
Soon after the first successful telegraph systems were operational, the possibility of transmitting messages across the sea by way of [[submarine communications cable]]s was first proposed. One of the primary technical challenges was to sufficiently insulate the submarine cable to prevent the electric current from leaking out into the water. In 1842, a Scottish surgeon [[William Montgomerie]]<ref name=Haigh26>{{cite book |last=Haigh |first=K R |title=Cable Ships and Submarine Cables |year=1968 |publisher=Adlard Coles Ltd |location=London |pages=26–27}}</ref> introduced [[gutta-percha]], the adhesive juice of the ''[[Palaquium gutta]]'' tree, to Europe. [[Michael Faraday]] and Wheatstone soon discovered the merits of gutta-percha as an insulator, and in 1845, the latter suggested that it should be employed to cover the wire which was proposed to be laid from [[Dover]] to [[Calais]]. Gutta-percha was used as insulation on a wire laid across the [[Rhine]] between [[Cologne-Deutz|Deutz]] and [[Cologne]].<ref>Bright, Charles (1898). ''[[iarchive:cihm_00867|Submarine telegraphs [microform] : their history, construction, and working]] : founded in part on Wünschendorff's 'Traité de télé graphie sous-marine''. Canadiana.org. London: C. Lockwood. p. 251.</ref> In 1849, [[C. V. Walker]], electrician to the [[South Eastern Railway (UK)|South Eastern Railway]], submerged a {{convert|2|mi|km}} wire coated with gutta-percha off the coast from Folkestone, which was tested successfully.<ref name=Haigh26/>

[[John Watkins Brett]], an engineer from [[Bristol]], sought and obtained permission from [[Louis-Philippe]] in 1847 to establish [[telegraph|telegraphic communication]] between France and England. The first undersea cable was laid in 1850, connecting the two countries and was followed by connections to Ireland and the Low Countries.

The [[Atlantic Telegraph Company]] was formed in [[London]] in 1856 to undertake to construct a commercial telegraph cable across the Atlantic Ocean. It was successfully completed on 18 July 1866 by the ship [[SS Great Eastern|SS ''Great Eastern'']], captained by [[James Anderson (sea captain)|Sir James Anderson]], after many mishaps along the way.<ref>{{cite book |last=Wilson |first=Arthur |year=1994 |title=The Living Rock: The Story of Metals Since Earliest Times and Their Impact on Civilization |page=203 |publisher=Woodhead Publishing |isbn=9781855733015}}</ref> John Pender, one of the men on the Great Eastern, later founded several telecommunications companies primarily laying cables between Britain and Southeast Asia.<ref>{{Cite journal |last=Müller |first=Simone |date=2010 |title=The Transatlantic Telegraphs and the 'Class of 1866' – the Formative Years of Transnational Networks in Telegraphic Space, 1858–1884/89 |journal=Historical Social Research / Historische Sozialforschung |volume=35 |issue=1 (131) |pages=237–259 |jstor=20762437 |issn=0172-6404}}</ref> Earlier transatlantic [[submarine communications cable|submarine cables]] installations were attempted in 1857, 1858 and 1865. The 1857 cable only operated intermittently for a few days or weeks before it failed. The study of underwater telegraph cables accelerated interest in mathematical analysis of very long [[transmission line]]s. The telegraph lines from Britain to India were connected in 1870. (Those several companies combined to form the ''Eastern Telegraph Company'' in 1872.) The HMS ''Challenger'' expedition in 1873–1876 mapped the ocean floor for future underwater telegraph cables.<ref>{{Cite book |last=Starosielski |first=Nicole |title=The Undersea Network |date=2015 |publisher=Duke University Press |isbn=978-0-8223-7622-4 |page=203 |chapter=Cabled Depths: The Aquatic Afterlives of Signal Traffic |doi=10.1215/9780822376224 |s2cid=114607440}}</ref>

Australia was first linked to the rest of the world in October 1872 by a submarine telegraph cable at Darwin.<ref>{{cite book |last1=Briggs |first1=Asa |last2=Burke |first2=Peter |title=A Social History of the Media: From Gutenberg to the Internet |page=110 |publisher=Polity |location=Cambridge |year=2005 |isbn=9780745635118}}</ref> This brought news reports from the rest of the world.<ref>{{cite book |last1=Conley |first1=David |last2=Lamble |first2=Stephen |year=2006 |title=The Daily Miracle: An introduction to Journalism |edition=3 |publisher=Oxford University Press |location=Australia |pages=305–307}}</ref> The telegraph across the Pacific was completed in 1902, finally encircling the world.

From the 1850s until well into the 20th century, British submarine cable systems dominated the world system. This was set out as a formal strategic goal, which became known as the [[All Red Line]].<ref name="kennedy197110">{{cite journal |jstor=563928 |title=Imperial Cable Communications and Strategy, 1870–1914 |author=Kennedy, P. M. |journal=The English Historical Review |date=October 1971 |volume=86 |issue=341 |pages=728–752 |doi=10.1093/ehr/lxxxvi.cccxli.728}}</ref> In 1896, there were thirty cable laying ships in the world and twenty-four of them were owned by British companies. In 1892, British companies owned and operated two-thirds of the world's cables and by 1923, their share was still 42.7 percent.<ref>{{cite journal |last1=Headrick |first1=D.R. |last2=Griset |first2=P. |year=2001 |title=Submarine telegraph cables: business and politics, 1838–1939 |journal=The Business History Review |volume=75 |issue=3 |pages=543–578 |doi=10.2307/3116386 |jstor=3116386 |s2cid=153560358}}</ref>