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The same year, another company tried using an insulated cable inside a [[hemp rope]] on the Portpatrick to Donaghadee route. This construction proved problematic because it floated (the Submarine Telegraph Company's Dover to Calais cable in 1850 was also lightweight, having no protection at all other than the insulation, but they had taken the precaution of adding periodic lead weights to sink the cable<ref>Smith, pp. 7-8</ref>). The strong sea currents in the [[Irish Sea]], deeper than the English Channel, dragged the cable into a large bow and there was consequently insufficient length to land it. The attempt was abandonded.<ref>Smith, p. 22</ref>
The same year, another company tried using an insulated cable inside a [[hemp rope]] on the Portpatrick to Donaghadee route. This construction proved problematic because it floated (the Submarine Telegraph Company's Dover to Calais cable in 1850 was also lightweight, having no protection at all other than the insulation, but they had taken the precaution of adding periodic lead weights to sink the cable<ref>Smith, pp. 7-8</ref>). The strong sea currents in the [[Irish Sea]], deeper than the English Channel, dragged the cable into a large bow and there was consequently insufficient length to land it. The attempt was abandonded.<ref>Smith, p. 22</ref>


{{anchor|Sand battery}}Magnetic were more careful in testing the insulation of batches of cable than Newall. Coils of cable were hung over the side of the dock and left to soak before testing. They used a new type of battery for [[insulation testing]] that was capable of being used at sea. Previously, the test batteries had been lined wooden cases with liquid [[electrolyte]] ([[Daniell cell]]). The new battery comprised a moulded gutta-percha case filled with sand saturated with electrolyte making it virtually unspillable. It was known as the "sand battery". 144 [[Electrochemical cell|cells]] were used in series (around {{nowrap|150 V}}). Several suspect portions of insulation were removed and repaired by opening up the iron wire armouring with [[Spanish windlass]]es.<ref>Smith, pp. 22-23</ref> The cable was laid in 1852 by the cattle ship ''Brittania'' (built 1827 at [[Yarmouth]]<ref>Haigh, p. 36</ref>). The cable was too taut as she sailed from Portpatrick resulting in the test instruments being dragged into the sea. Several delays caused by broken iron wires as the cable was laid resulted in the ship drifting off course and running out of cable and this attempt too was abandoned.<ref>Smith, p. 24</ref>
{{anchor|Sand battery}}Magnetic were more careful in testing the insulation of batches of cable than Newall. Coils of cable were hung over the side of the dock and left to soak before testing. They used a new type of battery for [[insulation testing]] that was capable of being used at sea. Previously, the test batteries had been lined wooden cases with liquid [[electrolyte]] ([[Daniell cell]]). The new battery comprised a moulded gutta-percha case filled with sand saturated with electrolyte making it virtually unspillable. It was known as the "sand battery". 144 [[Electrochemical cell|cells]] were used in series (around {{nowrap|150 V}}). Several suspect portions of insulation were removed and repaired by opening up the iron wire armouring with [[Spanish windlass]]es.<ref>Smith, pp. 22-23</ref> The cable was laid in 1852 by the cattle ship ''Brittania'' (built 1827 at [[Yarmouth]]{{dn|date=February 2019}}<ref>Haigh, p. 36</ref>). The cable was too taut as she sailed from Portpatrick resulting in the test instruments being dragged into the sea. Several delays caused by broken iron wires as the cable was laid resulted in the ship drifting off course and running out of cable and this attempt too was abandoned.<ref>Smith, p. 24</ref>


Magnetic were successful with a new cable in 1853 over the same route.<ref>Ash, p. 22</ref> This was a six-core cable and heavier than the 1852 cable, weighing seven [[ton]]s per mile. At over 180 [[fathom]]s down, it was the deepest cable laid to that date.<ref>Bright, p. 14</ref> Repairs to the cable in 1861 required 128 splices. Tests on pieces of retrieved cable found that the copper wire used was very impure, containing less than 50% copper despite the Gutta Percha Company specifying 85%.<ref>Smith, p. 101</ref>
Magnetic were successful with a new cable in 1853 over the same route.<ref>Ash, p. 22</ref> This was a six-core cable and heavier than the 1852 cable, weighing seven [[ton]]s per mile. At over 180 [[fathom]]s down, it was the deepest cable laid to that date.<ref>Bright, p. 14</ref> Repairs to the cable in 1861 required 128 splices. Tests on pieces of retrieved cable found that the copper wire used was very impure, containing less than 50% copper despite the Gutta Percha Company specifying 85%.<ref>Smith, p. 101</ref>

Revision as of 09:44, 8 February 2019

Company telegraph stamp

The British and Irish Magnetic Telegraph Company (Magnetic Telegraph Company or just Magnetic for short) was the principle 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.

Company history

Stamp of the English and Irish Magnetic Telegraph Company

The English and Irish Magnetic Telegraph Company was established by John Brett in 1850.[1] John Pender also had an interest[2] and Charles Tilston Bright was the chief engineer.[3] The company's initial objective was to connect Britain with Ireland following the success of the Submarine Telegraph Company in connecting England with France with the first ocean cable to be put in service.[4] The British and Irish Magnetic Telegraph Company was formed in 1857[note 1] in Liverpool through a merger of the English and Irish Magnetic Telegraph Company and the British Electric Telegraph Company.[5]

The main competitor of the Magnetic was the Electric Telegraph Company, later, after a merger, the Electric and International Telegraph Company ("the Electric" for short) founded by William Fothergill Cooke. By the end of the 1850s, the Electric and Magnetic companies were virtually a cartel in Britain.[6]

The company had a close relationship with the Submarine Telegraph Company who laid the first cable to France and many subsequent submarine telegraph cables to Europe. From about 1857 the Magnetic had an agreement with them that all their submarine cables were to be used only with the landlines of the Magnetic.[7] The Magnetic also had control of the first cable to Ireland. This control of international traffic gave them a significant advantage in the domestic market.[8]

The Magnetic founded its own press agency. It promoted its agency by offering lower rates to customers who used it than the rates for customers who wanted connections to rival agencies.[9] In 1870, The Magnetic, along with several other telegraph companies including the Electric, were nationalised under the Telegraph Act 1868 and the company wound up.[10]

Telegraph system

Plan view of the Henley and Foster two-needle telegraph

The telegraph system of the Magnetic was somewhat different from other companies. This was largely because the Electric held the patents for the Cooke and Wheatstone telegraph.[11] The name of the company refers to the fact that their telegraph system did not require batteries. Power for the transmissions was generated electromagnetically.[12] The system, invented by William Thomas Henley and George Foster, was a needle telegraph and came in double-needle or single-needle versions. The current was generated by the operator pressing pedal keys which in turn caused a deflection of the corresponding needle. The code consisted of various combinations of successive needle deflections to the left or right.[13]

The Magnetic found a method of overcoming the problem of dispersion on long submarine telegraph cables. The poorly understood phenomenon at that time was called retardation because different parts of a telegraph pulse travels at different speeds on the cable. Part of the pulse appears to be "retarded", arriving later than the rest at the destination. This "smearing out" of the pulse interferes with neigbouring pulses making the transmission unintelligble unless messages are sent at a much slower speed. The Magnetic found that if they generated pulses of opposite polarity to the main pulse and slightly delayed from it, the retarded signal was sufficiently cancelled to make the line usable at normal operator speeds.[14]

The Magnetic played a part in solving the dispersion problem on the transatlantic telegraph cable of the Atlantic Telegraph Company. Magnetic were strongly connected with this project; Bright promoted it and shares were sold largely to Magnetic shareholders, including Pender.[15] Dispersion on the 1858 Atlantic cable had been so severe that it was almost unusable and was destroyed by misguided attempts to overcome it with high voltage.[16] For the 1866 cable, it was planned to use the Magnetic's opposite polarity pulse method but doubts were expressed over whether it would work over such a great distance. Magnetic connected together various of their British underground cables to provide a total line length of over 2,000 miles for proof of principle testing.[17] Dispersion was not eliminated from submarine cables until loading coils started to be used on them from 1906 onwards.[18]

Telegraph network

First connection to Ireland

The company's first project was a submarine telegraph cable between Portpatrick in Scotland and Donaghadee in Ireland in 1852.[19] The cable core was gutta-percha insulated copper wire made by the Gutta Percha Company. This was armoured with iron wires by Newall and Company at their works in Sunderland. At the same time, Newall secretly constructed another cable at Gateshead with the intention of being first to get a telegraph connection to Ireland. The Newall cable was only lightly armoured with an open "bird-cage" structure of the iron wires, there was no cushioning layer between the core and the armour, and the insulation was not properly tested before laying because of the great hurry to get the job done before Magnetic. It was laid from Holyhead in Wales to Howth in Ireland[note 2] with William Henry Woodhouse as engineer, and thence to Dublin via underground cable along the railway line. The submarine cable failed a few days after laying and was never put into service.[20]

The same year, another company tried using an insulated cable inside a hemp rope on the Portpatrick to Donaghadee route. This construction proved problematic because it floated (the Submarine Telegraph Company's Dover to Calais cable in 1850 was also lightweight, having no protection at all other than the insulation, but they had taken the precaution of adding periodic lead weights to sink the cable[21]). The strong sea currents in the Irish Sea, deeper than the English Channel, dragged the cable into a large bow and there was consequently insufficient length to land it. The attempt was abandonded.[22]

Magnetic were more careful in testing the insulation of batches of cable than Newall. Coils of cable were hung over the side of the dock and left to soak before testing. They used a new type of battery for insulation testing that was capable of being used at sea. Previously, the test batteries had been lined wooden cases with liquid electrolyte (Daniell cell). The new battery comprised a moulded gutta-percha case filled with sand saturated with electrolyte making it virtually unspillable. It was known as the "sand battery". 144 cells were used in series (around 150 V). Several suspect portions of insulation were removed and repaired by opening up the iron wire armouring with Spanish windlasses.[23] The cable was laid in 1852 by the cattle ship Brittania (built 1827 at Yarmouth[disambiguation needed][24]). The cable was too taut as she sailed from Portpatrick resulting in the test instruments being dragged into the sea. Several delays caused by broken iron wires as the cable was laid resulted in the ship drifting off course and running out of cable and this attempt too was abandoned.[25]

Magnetic were successful with a new cable in 1853 over the same route.[26] This was a six-core cable and heavier than the 1852 cable, weighing seven tons per mile. At over 180 fathoms down, it was the deepest cable laid to that date.[27] Repairs to the cable in 1861 required 128 splices. Tests on pieces of retrieved cable found that the copper wire used was very impure, containing less than 50% copper despite the Gutta Percha Company specifying 85%.[28]

Land network

The Magnetic's network was centred on nothern England, Scotland, and Ireland, with its headquarters in Liverpool. Like most other telegraph companies, it ran its major telegraph trunk lines along railways in its home area.[29] One of their first lines was ten unarmoured wires buried in the space between two railway tracks of the Lancashire and Yorkshire Railway.[30] The Magnetic developed an extensive underground cable network from 1851 onwards.[31] This was in contrast to other companies who used wires suspended between telegraph poles, or, in built up areas, from rooftop to rooftop.[32] Partly, the Magnetic buried cables for better protection from the elements.[33] However, a more pressing reason was that many railway companies had exclusive agreemnents with the Electric which shut out the Magnetic.[34] Further, the British Telegraph Company, had exclusive rights for overhead lines on public roads, and the United Kingdom Telegraph Company had exclusive rights along canals.[35] The Magnetic had a particular problem in reaching London. Their solution was to run buried cables along major roads. Ten wires were installed in this way along the route London–Birmingham–Manchester–Glasgow–Carlisle.[36]

Wires on poles do not need to be electrically insulated (although they may have a protective coating). This is not so with underground lines. These must be insulated from the ground and from each other. The insulation must also be waterproof.[37] Good insulating materials were not available in the early days of telegraphy, but after William Montgomerie sent samples of gutta-percha to Europe in 1843, the Gutta Percha Company started making gutta-percha insulated electrical cable from 1848 onwards.[38] Gutta-percha is a natural rubber that is thermoplastic, so is good for continuous processes like cable making. Synthetic thermoplastic insulating material was not available until the invention of polyethylene in the 1930s and it was not used for submarine cables until the 1940s.[39] On cooling, gutta-percha is hard, durable, and waterproof making it ideal for underground (and later submarine) cables. This was the cable chosen by the Magnetic for its underground lines.[40]

In Ireland too, the Magnetic developed an extensive network of underground cables. In 1851, in anticipation of the submarine cable connection being laid to Donaghadee, the Magnetic laid an underground cable to Dublin.[41] Once the submarine link was in place, Dublin could be connected to London via Manchester and Liverpool. In the west of Ireland, by 1855 they had laid cables that stretched down the entire length of the island on the route Portrush–Sligo–Galway–Limerick–Tralee–Cape Clear.[42]

In 1856, the Magnetic discovered that the insulation of cables laid in dry soil was deteriorating. This was due to the essential oils in the gutta-percha evaporating leaving just a porous woody residue. Bright tried to overcome this by reinjecting the oils, but with limited success. This problem was the main driver for acquiring the unprofitable British Telegraph Company—so that the Magnetic inherited their overhead cable rights. From this point, the Magnetic avoided laying new underground cables except where it was essential to do so.[43]

Social issues

The Magnetic was an early advocate of employing women as telegraph operators. They were paid according to the speed with wich they could send messages, up to the maximum of ten shillings per week when 10 wpm was achieved. It was a popular job with unmarried women who otherwise had few good options.[44]

Notes

  1. ^ Hills, p. 294, citing Barty-King, p. 11, says the date was 1856.
  2. ^ Huurdeman, p. 129, credits the laying of this cable to the Magnetic Company.

References

  1. ^
    • Huurdeman, p. 129
    • Hills, p. 294
  2. ^ Hills, p. 294
  3. ^ Huurdeman, p. 129
  4. ^ Smith, p. 21
  5. ^ Beauchamp, p. 77
  6. ^ Hills, p. 22
  7. ^ Bright & Bright, pp. 73-74
  8. ^ Hills, pp. 62-63
  9. ^ Hills, p. 66
  10. ^
    • Bright, p. 110
    • Bright & Bright, p. 74
  11. ^ Mercer, p. 8
  12. ^ Beauchamp, p. 77
  13. ^ Schaffner, pp. 163-166
  14. ^ Bright, p. 26
  15. ^ Bright, 31-32
  16. ^ Hunt, p. 64
  17. ^ Bright, pp. 25-26
  18. ^ Newell, p. 478
  19. ^ Smith, p. 21
  20. ^
    • Smith, pp. 21-22
    • Bright, pp. 13-14
  21. ^ Smith, pp. 7-8
  22. ^ Smith, p. 22
  23. ^ Smith, pp. 22-23
  24. ^ Haigh, p. 36
  25. ^ Smith, p. 24
  26. ^ Ash, p. 22
  27. ^ Bright, p. 14
  28. ^ Smith, p. 101
  29. ^ Beauchamp, p. 77
  30. ^ Smith, pp. 302-303
  31. ^ Bright, p. 5
  32. ^ Beauchamp, p. 77
  33. ^ Bright & Bright, p. 73
  34. ^ Bright, p. 5
  35. ^ Bright & Bright, pp. 74-75
  36. ^ Bright, p. 5
  37. ^ Wheen, p. 83
  38. ^ Haigh, pp. 26-27
  39. ^ Ash, p. 29
  40. ^ Beauchamp, p. 77
  41. ^ Bright, p. 25
  42. ^ Bright, p. 24
  43. ^ Bright & Bright, pp.72-73
  44. ^ Beauchamp, p. 77

Bibliography

  • Ash, Stewart, "The development of submarine cables", ch. 1 in, Burnett, Douglas R.; Beckman, Robert; Davenport, Tara M., Submarine Cables: The Handbook of Law and Policy, Martinus Nijhoff Publishers, 2014 ISBN 9789004260320.
  • Barty-King, Hugh, Girdle Round the Earth: The Story of Cable and Wireless and Its Predecessors to Mark the Group's Jubilee, 1929-1979, London: Heinemann, 1979 OCLC 6809756, ISBN 0434049026.
  • Beauchamp, Ken, History of Telegraphy, Institution of Engineering and Technology, 2001 ISBN 0852967926.
  • Bright, Charles Tilston, Submarine Telegraphs, London: Crosby Lockwood, 1898 OCLC 776529627.
  • Bright, Edward Brailsford; Bright, Charles, The Life Story of the Late Sir Charles Tilston Bright, Civil Engineer, Cambridge University Press, 2012 ISBN 1108052886 (first published 1898).
  • Haigh, Kenneth Richardson, Cableships and Submarine Cables, Adlard Coles, 1968 OCLC 497380538.
  • Hills, Jill, The Struggle for Control of Global Communication,University of Illinois Press, 2002 ISBN 0252027574.
  • Hunt, Bruce J., The Maxwellians, Cornell University Press, 2005 ISBN 0801482348.
  • Huudeman, Anton A., The Worldwide History of Telecommunications, Wiley, 2003 ISBN 0471205052.
  • Mercer, David, The Telephone: The Life Story of a Technology, Greenwood Publishing Group, 2006 ISBN 031333207X.
  • Newell, E.L., "Loading coils for ocean cables", Transactions of the American Institute of Electrical Engineers, Part I: Communication and Electronics, vol. 76, iss. 4, pp. 478-482, September 1957.
  • Shaffner, Taliaferro Preston, "Magneto-electric battery", Shaffner's Telegraph Companion, vol. 2, pp. 162-167, 1855 OCLC 191123856. See also, Catalogue of the Special Loan Collection of Scientific Apparatus at the South Kensington Museum, p. 205, 1876.
  • Smith, Willoughby, The Rise and Extension of Submarine Telegraphy, London: J.S. Virtue & Co., 1891 OCLC 1079820592.
  • Wheen, Andrew, Dot-Dash to Dot.Com: How Modern Telecommunications Evolved from the Telegraph to the Internet, Springer, 2010 ISBN 1441967605.
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