Bertram Hopkinson CMG FRS MIEE MICE (11 January 1874 – 26 August 1918) was a British patent lawyer and Professor of Mechanism and Applied Mechanics at Cambridge University. In this position he researched flames, explosions and metallurgy and became a pioneer designer of the internal combustion engine.
Hopkinson was born in Birmingham, in 1874, the son of John Hopkinson an electrical engineer. He read law at Trinity College, Cambridge, and became a lawyer after his graduation. Following the death of his father, brother and two of his sisters in a mountaineering accident in 1898, Hopkinson switched to a career in engineering instead.
In 1903, Hopkinson was elected to the Cambridge chair in mechanism and applied mechanics, and in 1910 he was elected a Fellow of the Royal Society. During World War I he was commissioned into the Royal Engineers, and opened a research establishment at Orford Ness where he and his team researched weapons, sights, and ammunition. In 1915, Hopkinson discovered a similarity relation between the masses of explosive charges and their effects at a given distance. The same similarity relation was discovered independently in 1925 by Karl Julius Cranz in Germany. He learnt to fly and died on 26 August 1918 when his Bristol Fighter crashed en route from Martlesham Heath to London.