John Joly
John Joly (born November 1, 1857 in Bracknagh , County Offaly , Ireland ; † December 8, 1933 in Dublin ) was an Irish physicist and geologist who studied radioactivity and used it in medicine (radiotherapy) and geological age determination. He is also known for contributions to color photography and plant physiology.
Life
Joly began studying engineering at Trinity College Dublin in 1876, graduating in 1882, also studying modern literature and other subjects. After graduation, he was a demonstrator in the engineering and physics departments of Trinity College. In 1897 he succeeded William Johnson Sollas professor of geology and mineralogy at Trinity College, which he remained until his death.
In 1899 he proposed a method to determine the age of the earth from the sodium content of the oceans, based on the idea that its concentration would steadily increase through erosion on land. He then estimated the age of the earth to be 80 to 100 million years. In 1903 he proposed a better method, estimating the geological age from the radioactive decay of radium (in a Nature article). He worked in this area with Ernest Rutherford and concluded from his research in 1913 that the beginning of the Devonian was at least 400 million years ago. He also discussed uranium and other radioactive elements as sources of heat from the earth's interior, for example in the Presidential Address of the British Association at their meeting in Dublin in 1908 ( Uranium and Geology ).
He also used radioactivity in medicine after developing a chemical method for extracting radium in 1914. He developed a method of cancer therapy with radium, which was inserted into the body through a hollow needle. On his initiative, the Irish Radium Institute was founded and he worked on cancer therapy with the Dr. Steevens Hospital in Dublin.
He developed various instruments such as a photometer , a device for measuring the melting point of minerals, a calorimeter , a thermometer and a method for color photography named after him ( Joly line screen method , 1894).
With his friend Henry Horatio Dixon (1869-1953), professor of biology at Trinity College, he developed in 1894 a cohesion theory of water and mineral transport in the xylem of plants.
In 1923 he received the Murchison Medal . He was a Fellow of the Royal Society , whose Royal Medal he received in 1910. In 1911 he received the Boyle Medal from the Royal Dublin Society , of which he had been a member since 1881. In 1908 he was President of Section C of the British Association for the Advancement of Science . In 1930 he became a member of what was then the Soviet Academy of Sciences . He has received multiple honorary doctorates ( National University of Ireland , Cambridge University , University of Michigan ). Joly Memorial Lectures are still held at Dublin University today.
In 1973 a crater on Mars was named after him.
Web links
Individual evidence
- ↑ An estimate of the geological age of the earth , Scientific Transactions Royal Dublin Society
| personal data | |
|---|---|
| SURNAME | Joly, John |
| BRIEF DESCRIPTION | Irish physicist |
| DATE OF BIRTH | November 1, 1857 |
| PLACE OF BIRTH | Bracknagh |
| DATE OF DEATH | December 8, 1933 |
| Place of death | Dublin |