John Jolly

John Joly (1 November 1857 – 8 December 1933) was an Irish physicist and professor of geology at the University of Dublin, known for his development of radiotherapy in the treatment of cancer. He is also known for developing techniques to more accurately estimate the age of a geological period, based on radioactive elements present in minerals, the uranium–thorium dating.

Joly also invented a photometer for measuring light intensity, a meldometer for measuring the melting points of minerals, a differential steam calorimeter for measuring specific heats and a constant-volume gas thermometer, all of which bear his name, together with one of the first color photographic processes, the Joly colour screen. It was the first successful process for producing color images from a single photographic plate.

Joly was elected a Fellow of the Royal Society of London in 1892, was awarded the Boyle Medal of the Royal Dublin Society in 1911, the Royal Medal of the Royal Society of London in 1910, and the Murchison Medal of the Geological Society of London in 1923. He was also conferred honorary degrees by the National University of Ireland, the University of Cambridge, and the University of Michigan. After his death, his friends subscribed the sum of £1,700 to set up a memorial fund which is still used to promote the annual Joly Memorial Lectures at the University of Dublin, which were inaugurated by Sir Ernest Rutherford in 1935. He is also remembered by the Joly Geological Society, a student geological association established in 1960.[9]

In 1930 Oliver Sheppard was commissioned by Trinity College Dublin and the Royal Dublin Society to make them copies of a bust of Joly.

In 1973 a crater on Mars was named in his honour.