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By Jan Hicks on

Battle of the currents: the Hopkinson brothers

On the other side of the AC/DC battle to Ferranti, the Hopkinson brothers' campaign for a DC supply was most effective in Manchester.

Have you ever paused to think about how great engineers are? We love engineers at the Museum of Science and Industry. Engineering isn’t just about machinery, either.

Engineers are involved in the design of lots of things that make our lives easier, from roads and bridges, to pioneering medical treatments, and even the shape and texture of the chocolate bars we eat. 2018 is the Year of Engineering and this blog is going to celebrate the Hopkinson family of engineers from Manchester.

While Sebastian Ziani de Ferranti was developing his first alternator, used to generate alternating current, the other side of the ‘Battle of the Currents’ in the UK involved three brothers from the Hopkinson family. Two of the brothers worked with the Manchester company Mather & Platt, who were developing a new type of direct current dynamo, known as the Manchester Dynamo.

An example of a Manchester Dynamo built by Mather & Platt around 1886

This mini engineering dynasty was at the core of the development of electricity generation and supply in the UK at the end of the 19th century. They were involved in all sorts of projects across the country, not just designing dynamos in Manchester.

John Hopkinson (1824-1902) started things off when he joined Manchester company Wren and Bennett as an apprentice millwright. He eventually became an engineer, then a partner in the firm, which changed its name to Wren and Hopkinson. He married Alice Dewhurst of the Dewhurst cotton spinning family in Skipton, whom he met when Wren and Bennett supplied cotton machinery to the Dewhurst factory. Who said romance was dead? John and Alice had thirteen children – seven boys and six girls. The growing family moved to Grove House on Oxford Road in 1872. The house would later become the core building of the Whitworth Art Gallery when Sir Joseph Whitworth’s executors bought it from John Hopkinson. Its grounds became Whitworth Park.

According to one of his grandchildren, John Hopkinson had a store room at the top of Grove House that contained scientific apparatus including a Leyden jar and electrostatic generating equipment. He also cast metal cells at the Wren and Hopkinson works so that his eldest son, John Hopkinson (1849-1898), could build a galvanic battery.

Image of John Hopkinson (1849-1898) taken from the Science Museum Booklet John Hopkinson: Electrical Engineer

John Hopkinson is as important to the story of British electrical development as Sebastian Ziani de Ferranti. The two men shared similar experiences in their routes to becoming electrical engineers, starting out as child geniuses with fathers willing to support their scientific interests. In 1864, the year that Ferranti was born, John Hopkinson joined the new three-year engineering course at Owens College in Manchester. He was 15 years old. From there he went on to Cambridge to study mathematics. After graduation, he worked for a few months with his father at Wren and Hopkinson, but then moved to Birmingham to work in the Lighthouse Department of the optical engineers Chase Brothers. He spent five years at Chase Brothers, researching the use of arc lamps to illuminate lighthouses, coming up with an innovative method of grouping flashing lights that brought him to the attention of Sir William Thomson, later Lord Kelvin. The same Sir William Thomson who collaborated with Ferranti on his first alternator.

Hopkinson set himself up as a Consulting Engineer in 1877. He moved to London and began appearing as an expert witness in legal challenges to patents for scientific and technological innovations. He spent the next twenty years carrying out research that contributed to dynamo design, the theory of the operation of alternators, and electrical engineering practice.

Between 1879 and 1880, Hopkinson experimented with a Siemens dynamo to understand its performance and work out how that performance could be used to help maintain an electric arc. This dynamo is currently in the Science Museum collection, on loan from King’s College, London.

Image of the Siemens dynamo used by John Hopkinson, taken from the Science Museum Booklet John Hopkinson: Electrical Engineer

Following on from this research, in a paper he gave at the Institute of Civil Engineers in 1883, Hopkinson described electric circuits, dynamos, and AC and DC, and disproved the theory that a single large alternator was needed to supply consumers with electricity by demonstrating that running alternators in parallel produced a stable supply of AC electricity that could be transmitted to consumers.

From late 1881 until summer 1883, Hopkinson was the consulting engineer to the English Edison Company in London. He told the company directors that he needed to carry out a critical study of the Edison dynamo in order to identify improvements and make modifications to the machine. Since late 1882, the engineering company Mather & Platt had manufactured Edison dynamos for the UK market. Mather & Platt provided workshop space at its Salford works for Hopkinson to carry out tests. The tests enabled Hopkinson to introduce major innovations to the design of the Edison dynamos, reducing size, increasing output and improving efficiency. The Mather & Platt photograph album in the company archive, Photographs No.1, includes images of an Edison-Hopkinson dynamo in the workshop at Salford Ironworks. The earlier Siemens dynamo used by John Hopkinson in 1879-1880 seems to have influenced the design of this improved machine.

Pages from the Mather & Platt album Photographs No.1

The close working relationship Hopkinson had with Mather & Platt helped to establish the company’s electrical engineering department, which was a new departure for the firm. One of Hopkinson’s brothers, Edward Hopkinson (1859-1922) was the chief engineer of the new department, having previously worked as an engineer on electrical tramways with another brother, Charles Hopkinson (1854-1920). John and Edward worked together on the development of the Edison-Hopkinson dynamo, sales of which are recorded in the Mather & Platt Machine Sales Register for 1857-1884, found in the company archive at the museum.

Record of sales of the Edison-Hopkinson dynamo in 1884

The dynamo field models used by John and Edward Hopkinson in planning the redesign of the Edison dynamo are now in the Science Museum collection, on loan from King’s College.

Image of the Hopkinson brothers’ dynamo field models taken from the Science Museum Booklet John Hopkinson: Electrical Engineer

From their work on the Edison-Hopkinson machine, the brothers designed an innovative new dynamo, which Mather & Platt went on to develop. The Mather & Platt notebook Notes on Dynamos No.1 in the archive at the museum shows that testing of the new ‘M&P’ Dynamo started in November 1884. The new design was based on the first commercially successful electrical power generator, the Gramme dynamo. The Hopkinson brothers used a double magnetic circuit with a modified Gramme ring as the armature. The aim was to increase output through production of the most intense magnetic field possible. Patented a couple of weeks after testing, and renamed the ‘Manchester’ Dynamo, the machine was a great commercial success. Its main use was in textile mills and other industrial concerns.

Through collaboration with the Hopkinson brothers, Mather & Platt became a centre of science-based innovation and established its expertise in electrical power generation. Research into the Edison-Hopkinson and ‘Manchester’ dynamos continued into the 1890s. The Mather & Platt notebook Notes on Dynamos No.10 includes an entry for tests carried out on three Edison-Hopkinson dynamos for the John Rylands Library in Manchester.

Test entry for the Edison-Hopkinson dynamos supplied to John Rylands Library

Enriqueta Rylands commissioned the library, in memory of her husband, in 1889. It opened to the public in 1900. Electric lighting was chosen as a cleaner, safer alternative to gas, and the 110V DC supply was generated on site. The library was one of the first public buildings in Manchester to be lit by electric light. While carrying out research at John Rylands Special Collections into why the library used dynamos to generate power, rather than draw electricity from the existing Manchester Corporation DC supply, I discovered that Enriqueta Rylands had consulted John Hopkinson at an early stage of the library’s development. Mrs Rylands had also gone on to appoint the third electrical engineering Hopkinson brother, Charles, as Consultant Engineer for the library. The library’s architect Basil Champneys approved of this appointment, writing to Mrs Ryland’s manager William Linnell to say, “The advantage of having someone on the spot would be considerable and also I think would be an advantage in his working with his brother.”

John Hopkinson was instrumental in developing Manchester’s original electricity generating and supply network. He had provided expert evidence to the Select Committee on Electric Lighting in 1878-1879. The Select Committee’s findings resulted in the 1882 Electric Lighting Act. Following amendments to the Act in 1888, involvement in schemes to provide a public supply of electricity became more attractive to investors. In Manchester, the Corporation took the lead on lighting the city with electricity. In 1891, John Hopkinson became the Chief Engineer for Manchester’s Electric Lighting Works. Ten years previously, he had invented the three-wire system for conducting electricity, which reduced the cost of conductors and allowed the system to return excess electricity to the central station. In 1891, Hopkinson modified his three-wire system to create a five-wire system, improving the efficiency of electricity distribution even more. His system was taken up across the UK.

Sadly, John Hopkinson died in a mountaineering accident in Switzerland, along with three of his children. Edward Hopkinson went on to become vice-chairman of the Chloride Electrical Storage Company. Charles Hopkinson went into partnership with his nephew Bertram Hopkinson, John’s son who went on to become Professor of Engineering at Cambridge. Charles was also Chairman of the Building Committee for the Manchester Royal Infirmary building that opened in 1908 on Oxford Road. His achievements in life are remarkable because he was left deaf as a result of contracting scarlet fever in childhood.

The Hopkinson brothers feature in the upcoming exhibition Electricity: The spark of life, which opens on 18 October 2018. Look out, too, for a blog in January 2019 that will cover the John Rylands Library story in more depth.

2 comments on “Battle of the currents: the Hopkinson brothers

    1. Glad you enjoyed it, Ivan, and that it has been useful. If you’re visiting Manchester between 18 October 2018 and 28 April 2019, why not pop in to the exhibition to see our Manchester dynamo and some of the documents we hold on display?

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