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John Hopkinson (1849–1898) B. A., D.Sc., Fellow of Trinity College, Cambridge, electrical engineer ; later FRS.
1849 Born son of John Hopkinson (1824-1902)
Amongst many discoveries and inventions during a very fruitful career, particularly notable were his proposal of the three-wire system of electric distribution (1882), a theory of the design of dynamos (1886) and the identification of the theoretical basis for running alternators in parallel.
1878 Elected F.R.S.
1890 President of the Institution of Electrical Engineers in 1890 and 1896.
1898 Obituary 
Dr. JOHN HOPKINSON, eldest son of Alderman John Hopkinson, formerly Mayor of Manchester, was born in that city on 27th July 1849.
His school days were spent at Lindow Grove School near Manchester, and Queenwood College, Hampshire.
In 1864 he entered Owens College, Manchester, and distinguished himself in the mathematical and science classes.
In 1867 he entered Trinity College, Cambridge, being elected to the first foundation scholarship of the year; he had a distinguished academical career, obtaining the Sheepshanks astronomical scholarship, and graduating as senior wrangler and first Smith's prizeman in the mathematical tripos of 1871. After taking the scholarship in mathematics and natural philosophy at the bachelor of science degree, he graduated as doctor of science in pure and applied mathematics in the University of London. He was also one of the first of the Whitworth scholars.
After a short period spent in the engineering works of Messrs. Wren and Hopkinson, Manchester, he became in 1872 engineer and manager to the lighthouse and optical departments in the glass works of Messrs. Chance Brothers and Co. at Spon Lane near Birmingham.
There he introduced many minor improvements into the details of lighthouse work; and his association with this branch of engineering has left an indelible mark thereon. The system first suggested by Lord Kelvin, of distinguishing one light from another by flashes following at varied intervals, has been adopted by the Trinity House in the new Eddystone and other more recent lights, in the form introduced and perfected by Dr. Hopkinson, in which the principle is applied to revolving dioptric lights, so as to concentrate all the light into the flash.
Whilst with Messrs. Chance and in connection with lighthouse work, he first commenced to study the practical bearings of electrical machinery, and its relation to the theory of electric lighting.
In 1878 he removed to London, and commenced practice as a consulting engineer, continuing at the same time his connection with Messrs. Chance.
In April 1879 he read his first paper before this Institution upon electric lighting (Proceedings, page 238); and for the first time analysed the properties of the dynamo by means of "characteristic" curves.
The following year he read a further paper on the same subject (Proceedings 1880, page 266).
On the formation of the Edison company in London, he became their electrical adviser, and in this capacity made a thorough experimental investigation of the Edison dynamo, which led to the great improvements in efficiency and increased output that were embodied in the Edison-Hopkinson dynamo. In order more fully to determine the proper use of iron or steel in the dynamo, he ascertained experimentally the magnetic properties of iron and steel of various chemical composition, communicating the results to the Royal Society in a paper read in 1885. These investigations led to the synthetic method of predetermining the characteristic curves of dynamos, a method on which all modern dynamo construction is founded.
In 1886 this method was communicated to the Royal Society in a paper read in conjunction with his brother, Dr. Edward Hopkinson. Meanwhile his attention had not been exclusively devoted to the development of the continuous-current dynamo. In a lecture before the Institution of Civil Engineers in 1883 he had shown on theoretical grounds that alternate-current dynamos could be run in parallel; and in 1884 he had communicated a paper to the Institution of Electrical Engineers on the mathematical theory of alternate-current dynamos and motors, which was followed by a series of papers in subsequent years, published in the proceedings of the Royal Society and elsewhere, containing a complete investigation of alternating-current dynamos and transformers.
His scientific work was at the same time largely devoted to further researches into magnetic phenomena, especially into the magnetisation of iron at high temperatures and into recalescence. The extent of his investigations may be judged from the fact that in the course of twenty-one years he published no less than sixty papers on mechanical, electrical, and optical subjects, the majority of which are classical in the matters they deal with.
In 1894 he gave to this Institution (Proceedings, page 297) a description of the new electric lighting works, Manchester, which were constructed under his direction and came into operation in July 1893. These were the first electric supply works in the kingdom at which the voltage of 400 or upwards was adopted with continuous current, and was successfully carried out by distributing from a network of five conductors supplied by feeder mains—a development of his invention of the three-wire system.
He also introduced a method of charge, which gave to long-hour consumers an equitable reduction in price. The system of supply and charge proved eminently successful; and the Manchester demand for electricity is the largest in this country outside London, and is one of the most profitable.
He became a Member of this Institution in 1874, and from 1890 was a Member of Council. He was also a Fellow and royal medallist of the Royal Society, and a Member of Council of the Institution of Civil Engineers and of the British Association. He was President of the Institution of Electrical Engineers in 1890; and again in 1896, when he founded the corps of Electrical Engineer Volunteers, of which he was major in command at the time of his death.
He was killed in an Alpine accident during an ascent of one of the Petits Dents de Veisivi near Arolla in the canton of Valais, Switzerland, on 27th August 1898 at the age of forty-nine.
1899 Obituary 
JOHN HOPKINSON was born in Manchester on the 27th June, 1849. His father, who is still living and is a Member of this Institution, was a partner in a firm of manufacturing engineers.
John was the eldest of five sons, all of whom attained to success in their respective professions-a striking testimony to the excellence of their parental and early education. That there was a decided tendency in the family towards pursuits of a scientific character is shown by the fact that three of the brothers became engineers and one a Doctor of Medicine. The fifth, Alfred Hopkinson, who was second in order of age, took a different line, and is now Principal of Owens College, Manchester.
. . . after about twelve months spent at his father’s works, Hopkinson was offered the post of engineer and manager in the Lighthouse and Optical Department of the works of Chance Brothers, of Birmingham. . . . .
In 1878 John Hopkinson left Messrs. Chance Brothers and came to London, continuing, however, to be associated with that firm as Consulting Engineer. . . . .
Between 1881 and 1883 he worked as scientific adviser to the British Edison Company. During this time he made a significant improvement on the design of Edison's early dynamo.
In 1882 he obtained his well-known patent for the three-wire system of distributing electricity.
In 1890 Hopkinson was appointed Honorary Professor of the Electrical Engineering Laboratory at King’s College, London, . . . .
Until 1891 Hopkinson did not carry out any constructive engineering work of great importance. In that year, however, the Corporation of Manchester asked him to advise as to the electric lighting of that city. He reported on it, and in the two following years acted as Consulting Engineer in carrying out the work. . . . .
John Hopkinson had from a very early period taken a great interest in electric traction. In 1883 he patented the series-parallel control, describing it as applied to a hoist ; and in 1885 he invented a system of surface contacts for tramways. He acted as consulting engineer to the contractors for the electrical part of the City and South London Railway. His most important work of this kind was, however, done in 1896, when he superintended the making of the Kirkstall and Roundhay Tramway at Leeds. He had carefully observed tramway practice abroad, and did not introduce any novel features of importance into this line. It was, however, very successful, and at the time of his death he was engaged in carrying out large extensions. During the last two years of his life electric traction formed the greater part of his constructive work. . . .
Dr. Hopkinson’s premature death, at the age of 49, was the result of an Alpine accident. His son, John, and two of his daughters, also died in the accident. . . [More].
1899 Obituary 
JOHN HOPKINSON, M.A., D.Sc, F.R.S., was born in Manchester in 1849, the eldest of five brothers, all of whom have been possessed of marked ability in science. He followed his early schoolmaster, Mr. Willmore, from Lindon Grove School to Queenwood College in Hampshire.
He entered Owen's College in 1864, gained a scholarship in Trinity College, Cambridge in 1867, a Natural Science Exhibition and a Foundation Scholarship in Mathematics in 1868, became Doctor of Science of the University of London, both in mathematics and in mathematical physics, in 1870, was Senior Wrangler and first Smith's prizeman in 1871, and soon became a Fellow of Trinity.
After some experience in his father's engineering works in Manchester he became engineer and manager of the lighthouse and optical department of the glass works of Messrs. Chance Bros., of Birmingham.
His paper in the Proceedings of the Institution of Civil Engineers in 1883 will give some indication of his valuable work in connection with the design of optical apparatus and mechanism for lighthouses. He invented the very valuable and now much used "group-flash" system of working. He took an early interest in the use of the electric lighting of lighthouses, as is evidenced in a discussion at the Institution of Civil Engineers, vol. 57, 1877. Before this time (1876), and afterwards, he contributed greatly to our knowledge of residual charge in condensers (Phil. Trans., from 1876 to 1880, and indeed to 1897). His Birmingham experience gave him a thorough grasp of the true function of mathematics in engineering (see his James Forrest Lecture, Proc. Inst. C. E., vol. 108), and in 1878, when he came to London and was elected a Fellow of the Royal Society, he may be said to have possessed in perfection every quality characteristic of the good engineer.
From this time he followed the calling of an expert witness in patent cases, and he made it exceedingly lucrative. But, in spite of the engrossing nature of his professional work, he was able to do original experimental and mathematical work in pure and applied science, principally on the subject of electricity, which by itself was astonishing in amount. Thus he was awarded the Royal Society medal in 1890 for his many excellent contributions to natural knowledge, and even after he came to London he published nearly sixty valuable scientific papers. There was no theory of the dynamo till he gave us one in 1879 (Proc. Inst. Mech. Eng., 1879, 1880). He exhibited an alternate-current machine and an electric hoist (using for the first time the now common series-parallel system of working motors) at Paris in 1881. He invented the three-wire system of electric distribution in 1882. He began to improve the dynamo (see his lecture Inst. C.E., 1883) in 1883, and with his brother, Dr. E. Hopkinson, in 1886 (Phil. Trans., 1886) he published the principles which now guide all electrical engineers in designing electro-magnets. It is still in the memory of us all how the publication of this paper completely revolutionised the design of dynamo machines ; and if Dr. Hopkinson had done nothing else in his life electrical engineers would have regarded him as one of their greatest benefactors. His most important papers on the running of alternators in parallel were published in the Institutions of Civil and Electrical Engineers in 1883 and 1884, but others were read later before the Royal Society.
He became Honorary Professor of the Electrical Engineering Laboratory at King's College, London, in 1890, and from that time till his death carried out many investigations to verify and illustrate and extend his theories. The effect of Foucault currents on iron magnet cores; the best method of measurement of efficiency of transformers; the magnetic properties of iron and the effect of heat upon them—these are some of the subjects on which he published many valuable papers since 1890.
He acted as consulting engineer to the Corporation of Manchester from 1891, in carrying out their very important and successful system of electric lighting, introducing the then novel methods of charging customers for their supply which are now so common. The success of this work led to his being called upon to act in the same capacity in many other towns.
He designed and superintended the construction of the Leeds Electric Tramway system, and was devoting much time to systems of electric traction for two years before his death. He was greatly interested in engineering teaching, and took a special interest in the Engineering School at Cambridge, to which he was an early large subscriber of money. He was a member of the Senate of the University of London, a member of Council of the Institution of Civil Engineers, of the Physical Society of London, and of the British Association.
He was president of the Institution of Electrical Engineers in 1890, and again in 1896. Although ordinarily but little interested in political affairs, he was greatly moved by the events which took place towards the end of 1895, and became desirous of using his position as President of the Institution to further the cause of National defence. He conceived the idea that a technical corps of electrical engineers might be used with advantage for the purpose of coast-defence, and at the very commencement of his second term of Presidency of the Institution he proposed that a corps of electrical volunteers should be formed with that object. He saw that all the members of such a corps would probably be experts in the electrical work that would be required of them, and that it would only be necessary that they should familiarise themselves with the special forms of apparatus used in the service. After considerable preliminary discussion the corps was organised with Dr. Hopkinson in command, and the first training took place in the autumn of 1897. During the following year, 100 electrical volunteers were enrolled, and Dr. Hopkinson was present at the commencement of the second training in the Isle of Wight at the commencement of 1898, and to his great satisfaction saw that his predictions as lo the efficiency of the corps were fully verified.
At Cambridge he entered not only into the intellectual, but also into the physical life of the University. He was captain of the second Trinity boat, and won a college mile in very good time a few weeks before his Tripos. He was an enthusiastic and experienced Alpine climber.
On the 27th of August, 1898, with his second son and two elder daughters, he was climbing a mountain well known to him, the Petite Dent de Veisivi, near the Rhone Valley, and all four were accidentally killed. The experience of the party made a guide unnecessary, and there was no witness of the accident. His death at forty-nine was premature, but in spite of the fact that his professional work occupied nearly the whole of his time, it is difficult to read the record of his achievements in pure and applied science without thinking that he must have devoted to them the whole of a very long life.
Dr. Hepkinson was elected a Member of the Institution on the 10th of November, 1881, and became a Member of Council in 1883, a Vice-President in 1886, and President for the first time in 1890.
1898 Obituary