Submarine Cables, the First Medium

Transatlantic Cables and the Ohm

Submarine cables, the first medium for intercontinental communications, were pioneered by William Thomson (1824 – 1907), later Lord Kelvin, with Fleeming Jenkin (1833–1885), a school-friend of Maxwell who was the engineer in charge of international cable laying Transatlantic Cables and the Ohm operations before becoming Regius Professor of Engineering at The University of Edinburgh. Submarine cables,Transatlantic the first medium for intercontinental Cables communications, wereand pioneered the by Ohm William Thomson (1824 – 1907), later Lord Kelvin, with Fleeming Jenkin (1833–1885)In the, a 1850’s, Michael Faraday (1791 – 1867) and Thomson demonstrated how the core school-friend of Maxwell who was the engineer in charge of international cable laying resistance of the cable could limit messages to only one character every four seconds! It operations before becoming Regius Professor of Engineering at The University of was therefore important to know exactly what its resistance was. Edinburgh.

In the 1850’s, Michael Faraday (1791 – 1867) and Thomson demonstrated how theJenkin, core as secretary to the British Association Committee on Electrical Standards, appointed resistance of the cable could limit messages to only one character every four seconds!a committee It including Maxwell to define the “Standards of Electrical Resistance”. was therefore important to know exactly what its resistance was. Submarine cables, the first medium for intercontinental An instrument proposed by Thomson, as seen Jenkin, as secretarytelecommunications, to the British Association were pioneered Committee by on William Electrical Thomson Standards , appointed here alongside Maxwell, employed a magnet a committee including(1824 – Maxwell1907), later to define Lord theKelvin, “Standards with Fleeming of Electrical Jenkin Resistance”. (1833 suspended within a spinning coil of standard wire. – 1885), a school-friend of Maxwell who was the engineer Maxwell and Jenkin led the experimental An instrument proposed by Thomson, as seen verification of the coil resistance. Their reports, in charge of internationalhere cable alongside laying Maxwelloperations, employed before a magnet becoming Regius Professorsuspe of Engineeringnded within at a spinningThe University coil of standard wire. published along with others including those of of Edinburgh. Maxwell and Jenkin led the experimental Charles Wheatstone and Werner Siemens, verification of the coil resistance. Their reports, culminated in 1867 in the adoption of the unit that In the 1850’s, Michael Faradaypublished (1791 along – 1867) with and others Thomson including those of we now represent with the symbol Ω, after the demonstrated how the coreCharles resistance Wheatstone of the and cable Werner could Siemens , German physicist Georg Ohm. limit messages to only oneculminated character in every1867 infour the seconds!adoption of the unit that we now represent with the symbol , after the In 1873, Maxwell and Jenkin each published their It was therefore important to know exactly what itsΩ German physicist Georg individual textbooks on electricity and magnetism. resistance was. Ohm. In 1873, Maxwell and Jenkin each published their Jenkin, as secretary to theindividual British Associationtextbooks on Committee electricity and magnetism. Maxwell with his apparatus, courtesy IET Archives, London. on Electrical Standards, appointed a committee including Maxwell with his apparatus, courtesy IET Archives, London. Maxwell to define the “Standards of Electrical Resistance”. Maxwell with his apparatus, courtesy IET Archives, London.

An instrument proposed by Thomson, as seen here alongside Maxwell, employed a magnet suspended within a spinning coil of standard wire. Maxwell and Jenkin led the experimental verification of the coil resistance. Their reports, published along with others including those of Charles Wheatstone and Werner Siemens, culminated in 1867 in the adoption of the unit that we now represent with the symbol Ω, after the German physicist Georg Ohm.

In 1873, Maxwell and Jenkin each published their individual textbooks on

A letter from Maxwell to Siemens on the variation of resistance with electricity and magnetism. temperature. On the left is Maxwell’s original first page, while transcribed on the right is its conclusion, courtesy IET Archives, London.

This panel is sponsored by James Clerk Maxwell The Rt Hon the Lord Jenkin of Roding, Foundation Hon FRSE, the Great-Grandson of Fleeming Jenkin.

James Clerk Maxwell Foundation 2015