JOHN JOLY: X RAY TO IMPROVE SCIENCE

John Joly

John Joly (1857-1933) was an Irish physicist, famous for his development of radiotherapy in the treatment of cancer. He is also known for developing techniques to accurately estimate the age of a geological period, based on radioactive elements present in minerals.

Joly was born in Holywood House, the Church of Ireland Rectory, Bracknagh, County Offaly, Ireland. He was a second cousin of Charles Jasper Joly, the astronomer. He entered Trinity College, Dublin in 1876, graduating in Engineering in 1882 in first place with various special certificates in branches of engineering, at the same time obtaining a First Class Honours in modern literature.

Joly joined the Royal Dublin Society in 1881 while still a student, and was a frequent contributor of papers. His first scientific paper was published in 1883, on the use of meteorological instruments at a distance. 

On 17 May 1899 Joly read his paper, An Estimate of the Geological Age of the Earth to the Royal Dublin Society. In it, he proposed to calculate the age of the earth from the accumulation of sodium in the waters of the oceans. He calculated the rate at which the oceans should have accumulated sodium from erosion processes, and determined that the oceans were about 80 to 100 million years old.

More information: Trinity College

In 1903 he published an article in Nature in which he discussed the possibility of using radium to date the Earth and went on to study the radioactive content of the Earth's crust to formulate a theory of thermal cycles, and examined the radioactive constituents of certain rocks as a means of calculating their age. Working in collaboration with Sir Ernest Rutherford, he used radioactive decay in minerals to estimate, in 1913, that the beginning of the Devonian period could not be less than 400 million years ago, an estimate which is in line with modern calculations.

In 1914 he developed a method of extracting radium and applied it in the treatment of cancer. As a Governor of Dr Steevens' Hospital in Dublin, in collaboration with Walter Stevenson he devised radiotherapy methods and promoted the establishment by the Royal Dublin Society of the Irish Radium Institute where they pioneered the Dublin method of using a hollow needle for deep radiotherapy, a technique that later entered worldwide use. The Radium Institute also supplied capillary tubes containing radon to hospitals for some years for use in the treatment of tumours.

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 process. It was the first successful process for producing color images from a single photographic plate.

More information: Engineers Journal

Geological age plays the same part in our views of the duration 

of the universe as the Earth's orbital radius does in our views 

of the immensity of space. 

 John Joly

ERNEST T. S. WALTON, AN IRISH NOBEL PRIZE IN PHYSICS

Ernest Walton

Ernest Thomas Sinton Walton (1903-1995) was an Irish physicist and Nobel laureate for his work with John Cockcroft with atom-smashing experiments done at Cambridge University in the early 1930s, and so became the first person in history to artificially split the atom. 

He was born in Abbeyside, Dungarvan, County Waterford to a Methodist minister father, Rev John Walton and Anna Sinton. In those days a general clergyman's family moved once every three years, and this practice carried Ernest and his family, while he was a small child, to Rathkeale, County Limerick, where his mother died, and to County Monaghan. 

 

He attended day schools in counties Down and Tyrone, and at Wesley College Dublin before becoming a boarder at Methodist College Belfast in 1915, where he excelled in science and mathematics.

More information: Nobel Prize

In 1922 Walton won scholarships to Trinity College, Dublin for the study of mathematics and science. He was awarded bachelor's and master's degrees from Trinity in 1926 and 1927, respectively. During these years at college, Walton received numerous prizes for excellence in physics and mathematics, seven prizes in all, including the Foundation Scholarship in 1924. Following graduation he was awarded an 1851 Research Fellowship from the Royal Commission for the Exhibition of 1851 and was accepted as a research student at Trinity College, Cambridge, under the supervision of Sir Ernest Rutherford, Director of Cambridge University's Cavendish Laboratory. At the time there were four Nobel Prize laureates on the staff at the Cavendish lab and a further five were to emerge, including Walton and John Cockcroft. Walton was awarded his PhD in 1931 and remained at Cambridge as a researcher until 1934.

During the early 1930s Walton and John Cockcroft collaborated to build an apparatus that split the nuclei of lithium atoms by bombarding them with a stream of protons accelerated inside a high-voltage tube  of 700 kilovolts. The splitting of the lithium nuclei produced helium nuclei. This was experimental verification of theories about atomic structure that had been proposed earlier by Rutherford, George Gamow, and others. The successful apparatus, a type of particle accelerator now called the Cockcroft-Walton generator, helped to usher in an era of particle-accelerator-based experimental nuclear physics. It was this research at Cambridge in the early 1930s that won Walton and Cockcroft the Nobel Prize in physics in 1951.

Walton was associated with the Dublin Institute for Advanced Studies for over 40 years, serving long periods on the board of the School of Cosmic Physics and on the Council of the Institute. Following the 1952 death of John J. Nolan, the inaugural chairman of the School of Cosmic Physics, Walton assumed the role, and served in that position until 1960, when he was succeeded by John H. Poole.

More information: Irish Central

A linear accelerator has the advantage that no magnet is required 

and that its cost should not rise much more steeply than 

with the energy of the particles required. 

Ernest Walton