Physicist and Nobel laureate. Born in Widnes (Lancashire, England), Barkla was educated in Liverpool, graduating from University College in physics in 1898. He went to work in the Cavendish Laboratory at Cambridge and then King's College London before returning to a teaching position at Liverpool in 1905. He served as Professor of Physics at King's College (1909-13). In 1913 he accepted the Chair in Natural Philosophy at the University in Edinburgh and was elected a Fellow of the Royal Society of Edinburgh the following year. He is best known for his work with X-rays, and it was for his discovery of the characteristic X-ray radiation of the elements that he was awarded the Nobel Prize for Physics in 1917. He also discovered the polarisation of X-rays and proposed that they were waves in the same manner as light.
He died at his home, Braidwood, in Edinburgh. His life is commemorated by a plaque on the Institute of Geography building at the University of Edinburgh (formerly occupied by Natural Philosophy) and there is a lecture theatre named after him at the University of Liverpool.