Michael Faraday, English chemist and physicist, c 1850s.
© Science Museum / Science & Society Picture Library
Carte de visite photograph by John Watkins. Michael Faraday (1791-1867) discovered the principles of the electric motor and dynamo. Faraday's great life work was the series 'Experimental Researches on Electricity' published over 40 years in 'Philosophical Transactions', in which he described his many discoveries including electromagnetic induction (1831), the laws of electrolysis (1833) and the rotation of polarised light by magnetism (1845).