John Hopkinson was born the eldest of a large family of thirteen children. He was fortunate in that being brought up in Manchester he had good schooling and in 1865 entered Owens College in that city. Owens College, which went on to become the University of Manchester, was an excellent institution in which to study.
After showing great abilities in mathematics Hopkinson was awarded a scholarship to allow him to continue his study of that subject at Trinity College Cambridge. He entered Cambridge in 1867 and graduated with a mathematics degree in 1871. Although his scholarship would have allowed him to continue his mathematical studies at Cambridge, Hopkinson decided to put his mathematics to practical use in engineering.
There had been no chair of engineering at Owens College when Hopkinson studied there, but it is interesting to note that Osborne Reynolds was appointed to such a chair while Hopkinson was studying at Cambridge. In 1872 Hopkinson was appointed as the engineering manager of Chance Brothers and Company, a glass manufacturing company in Birmingham. There he studied the problems of efficient ways of shining lights from a lighthouse and, in particular, he recommended the use of flashing groups of lights.
Dibner writes in [1]:-
Hopkinson's application of Maxwell's electromagnetic theories to the analysis of residual charge and displacement in electrostatic capacity led to his election as a fellow of the Royal Society in 1877.
In 1878 Hopkinson founded his own electrical engineering company. Collaborating with Edward Hopkinson, one of his brothers, he applied the theory of electricity and magnetism to the development of electric motors. He used his mathematical expertise to give a general theory of alternating currents and he applied this theory to the operation of alternating current generators in parallel.
Hopkinson was appointed professor of electrical engineering at King's College London in 1890. At the same time he became director of the newly founded Siemens Laboratory.
When at the height of his powers Hopkinson was sadly killed in a mountaineering accident while on holiday in Switzerland. His son and two daughters died in the same accident on Mount Petite Dent de Veisivi.
Although Hopkinson's life was cut short by the accident, he had already received several honours for his contributions of applying mathematics to engineering. In addition to his election to the Royal Society which we mentioned above, he was President of the Institution of Electrical Engineers on two occasions.