Engineering Laid Bare: the First Transatlantic Telegraph Cables Celebrated in Exhibition

Guildhall Art Gallery, City of London, until 22 January 2017

The 150th anniversary of the first communication cables to be laid across the Atlantic Ocean, connecting Europe with America, is being celebrated between now and 22 January 2017 in a free exhibition entitled ‘Victorians Decoded: Art and Telegraphy’ at the City of London Corporation’s Guildhall Art Gallery. Special curator talks of the exhibition will take place on 24 November 2016, 15 December 2016 and 19 January 2017.

This exciting collaboration between Guildhall Art Gallery, King’s College London, The Courtauld Institute of Art and the Institute of Making at University College London explores how the first telegraph cables connecting the continents transformed communications with rare artefacts relating to their use and manufacture. These objects have been selected by Professor Mark Miodownik, Director at the Institute of Making and one of the UK’s most influential engineers and material scientists, and Dr Cassie Newland, a leading archaeologist and Research Associate at King’s College London. Miodownik and Newland are both well-known broadcast presenters and have co-hosted programmes such as the BBC 2’s The Genius of Invention. 

This exhibition features four themed rooms (Distance, Resistance, Transmission and Coding) featuring samples of Victorian transatlantic cables, one-of-a-kind prototype transmitters and devices developed by Victorian telegraphy pioneer Charles Wheatstone. ‘The Great Grammatizor’, a special messaging machine to encourage the public to take part in the exhibition and paintings by prominent Victorian artists will also be on display.

A new telegraphic world

It took nine years, four attempts and three cables until the Victorians successfully installed two transatlantic telegraphs from Valentia Island in Ireland to Newfoundland in Canada on 27th July and 7th September 1866.

The ability to send messages across continents in minutes (approximately one minute for every eight words) for the first time was a ‘moon landing moment’ for communications and telegraphic engineering, and (similar to the internet in recent decades) it sparked opportunities for businesses, governments, military forces and the public that were previously unimaginable.


Telegraph wires

The exhibition showcases samples of cables used in early British and French transatlantic telegraphs. These worked by sending electric signals down a copper core formed of seven wires. Gutta-percha, a natural plastic sourced from trees, insulated the conducting wires from each other and the ocean surrounding it. An outer layer of strandised iron armouring wires was used to provide strength and protect the cable from damage.


Engineering telegraph cables

Building transatlantic telegraph cables that were well insulated, sufficiently flexible to manoeuvre in the ocean and protected enough to withstand its environment was a challenge. The first transatlantic telegraph was actually laid in 1858 but engineers encountered massive electrical problems due to the resistance of the cable. It grew progressively worse and finally failed after three weeks. William Thomson correctly suspected that this was due impurities in the copper and faults in the insulation. Engineer Wildman Whitehouse was blamed for breaking the cable by sending a high voltage down it in an attempt to improve signal clarity. The 1865 and 1866 cables were built with far thicker copper conducting wires to reduce resistance and speed up message traffic. They used purer copper, had better insulation and were also more heavily armoured to prevent damage.


Amplifying transmission

The cores of early submarine cables were too thin and produced electrical effects that interfered with the sending of signals. Charles Wheatstone and other scientists therefore developed devices that amplified weak signals and improved our understanding of how electricity behaves. On display at the Guildhall Art Gallery is Wheatstone’s own prototype of the famous Wheatstone Bridge, a device used to discover an unknown resistance from known ones, and a Resistance Box that allowed engineers to create ‘dummy’ circuits of any length and resistance for experimenting with and testing equipment.


Coding messages

To shorten messages and hide secret content from telegraph clerks people used code books and ciphers. The exhibition showcases code books, some of Wheatstone’s encryption devices including a Cipher Post. A new interactive messaging machine, ‘The Great Grammatizor’, produces personal ‘coded’ poems for the public. Imagined as a bridge to the past by UCL PhD student Alexandra Bridarolli, the machine has three rotating buttons that represent ‘genre’, ‘feelings’ and ‘driving force’. When each is turned to one of seven options and a lever ‘cranked’ it will produce a one-of-a-kind text for visitors to decipher.


For more information, visit


About the Atlantic Telegraph

·         More detailed technical information can be found in this extract from the publication ‘Engineering Facts and Figures for 1866: An Annual Register of Progress in Mechanical Engineering and Construction’   


About Guildhall Art Gallery

·         Guildhall Art Gallery was established in 1886 as ‘a Collection of Art Treasures worthy of the capital city’.

·         See works dating from 1670 to the present, including seventeenth century portraits, Pre-Raphaelite masterpieces and a fascinating range of paintings documenting London’s dramatic history.

·         General admission to Guildhall Art Gallery is FREE; however, an entrance fee may be charged for some exhibitions, with concessionary rates for senior citizens, registered unemployed and registered disabled.

·         Opening times: 10am – 5pm (Monday – Saturday), 12pm – 4pm (Sunday)


About King’s College London

·         King’s College London is one of the top 20 universities in the world (2015/16 QS World University Rankings) and among the oldest in England. King’s has more than 27,600 students from some 150 countries worldwide, and some 6,800 staff.

·         King’s has an outstanding reputation for world-class teaching and cutting-edge research. In the 2014 Research Excellence Framework (REF) King’s was ranked 6th nationally in the ‘power’ ranking, which takes into account both the quality and quantity of research activity, and 7th for quality according to the Times Higher Education rankings. Eighty-four per cent of research at King’s was deemed ‘world-leading’ or ‘internationally excellent’ (3* and 4*). The university is in the top seven UK universities for research earnings and has an overall annual income of more than £684 million. See for more information.


About the City of London Corporation

·         The City of London Corporation provides local government and policing services for the financial and commercial heart of Britain, the ‘Square Mile’. The City Corporation has three roles:

·         It supports London’s communities by working in partnership with neighbouring boroughs on economic regeneration, education and skills projects. The City of London Corporation’s charity, the City Bridge Trust, makes grants of more than £15 million annually to charitable projects across London; and it also supports education with three independent schools, three academic schools, a primary school and the world-renowned Guildhall School of Music & Drama

·         It also helps look after key London heritage and green spaces including Tower Bridge, Museum of London, Barbican Centre, London Metropolitan Archives, City Gardens, Hampstead Heath, Epping Forest, Burnham Beeches, and important ‘commons’ in south London

·         It also supports and promotes the ‘City’ as the world’s leading international financial and business centre, with outward and inward business delegations, high-profile civic events, research-driven policies all reflecting a long-term approach. See for more details.


About the Courtauld Institute of Art

·         Based at Somerset House, The Courtauld Institute of Art is an independent college of the University of London and is one of the world’s leading centres for the study of art history, conservation and curatorship, and its Gallery houses one of Britain’s finest and best-loved collections.

·         Facilities for students are exceptional, including the outstanding collection of paintings, drawings and prints, sculpture and decorative arts.

·         Courtauld staff supervise research from classical antiquity to the present, and the Research Forum offers access to visiting speakers from around the world. Public lectures, short courses and lunchtime talks allow members of the public to share in the wealth of expertise at The Courtauld.

·         The Guardian ranked The Courtauld first for the study of art history in its 2017 University League Table. See for more information.