Died: 23 October 1944 in Braidwood, Edinburgh, Scotland

Charles Glover Barkla's father was John Martin Barkla, the Secretary of the Atlas Chemical Company, and his mother was Sarah Glover. Barkla studied at the Liverpool Institute then in 1894, after winning Bibby and county council scholarships, he entered Liverpool University College, at that time part of the Victoria University of Manchester. There he studied mathematics and physics under Oliver Lodge, graduating with First Class Honours in Physics in 1898 and, in the following year, he obtained his Master's Degree. Then, in 1899, he went to Trinity College, Cambridge but after one year moved to King's College, Cambridge. This was not for academic reasons, rather his chief recreation was singing - he had a powerful baritone voice - and the move allowed him to join the King's College Chapel Choir during 1901-1902. At Cambridge Barkla worked in the Cavendish Laboratory under J J Thomson. Falconer writes [3]:-

Barkla conceived a great admiration for Thomson, recalling that 'I felt that the papers that I wrote were for him to read: the appreciation of others was of quite secondary importance. His interest and his publications on and around the subject were then my greatest inspiration'.

In 1902 Barkla was appointed Oliver Lodge Fellow in Liverpool, later becoming an assistant lecturer in physics. He became Physics Lecturer in Advanced Electricity in Liverpool in 1907 but two years later was appointed Wheatstone Professor of Physics at King's College in the University of London. Four years later, in 1913, he was appointed to the Chair of Natural Philosophy in Edinburgh University. This was reported in The Scotsman on Wednesday, 9^th July 1913:-

NEW EDINBURGH PROFESSOR

Yesterday afternoon the Curators of Patronage of Edinburgh University appointed Professor Charles Glover Barkla, at present Wheatstone Professor of Physics, University of London, King's College, to the vacant Chair of Natural Philosophy in Edinburgh University, caused by the demise of Professor J G MacGregor. Professor Barkla is a graduate of both Liverpool (when part of the Victoria University) and Cambridge. He was a former student of Principal Sir Oliver Lodge, Birmingham, then Professor of Physics in Liverpool University College, who has described the newly elected Professor as the ablest student he had in Liverpool. In Liverpool he held the Bibby Scholarship and the Oliver Lodge Fellowship among his many honours, as well as an 1851 Exhibition Fellowship for three years (an extra year more than is usual.) After completing his course at King's College, Cambridge, and graduating he became a demonstrator in Physics, and later lecturer in advanced electricity in his old College, now Liverpool University, of which he is a D.Sc., as well as a B.Sc. and M.Sc., till in 1909 when elected to his present sphere. He has done much examining for the northern English Universities, and in original research the X-rays and Röntgen Rays have been his chief theme of study and subject of published works. As a teacher he has been very successful. On the Continent also his work has been appreciated by a grant from the Solvay International Institute (Brussels) of 2500 francs for his research work last year on Röntgen Radiation; while last month the German Physical Society invited him to give the annual lecture by a foreign savant at their Scientific and Medical Congress in Vienna next September. His subject is to be "Röntgen Radiation." In 1912 he received his Fellowship of the Royal Society.

Falconer writes [3]:-

Barkla took a prominent part in instituting honours degrees in pure science at Edinburgh and in developing the honours school of physics, modelling his leadership style on that of Thomson at the Cavendish.

Barkla married Mary Esther Cowell, the eldest daughter of John T Cowell of Douglas, Receiver-General of the Isle of Man, in 1907; they had two sons and one daughter. The youngest of their sons, Flight Lieutenant Michael Barkla, was a brilliant medical scholar, but sadly was killed in action in North Africa in 1943.

In [4] Barkla's research contributions are described in detail. The following provides an overview:-

Barkla's first researches concerned the velocity of electric waves along wires but in 1902 he commenced his investigations on Röntgen radiation which were to occupy almost his whole life. His discovery of homogeneous radiations characteristic of the elements showed that these elements had their characteristic line spectra in X-ray and he was the first to show that secondary emission is of two kinds, one consisting of X-rays scattered unchanged, and the other a fluorescent radiation peculiar to the particular substance. He discovered the polarisation of X-rays, an experimental result of considerable importance for it meant that X-radiation could be regarded as similar to ordinary light. Barkla made valuable contributions ... on the absorption and photographic action of X-rays and his later work demonstrated the relation between the characteristic X-radiation and the corpuscular radiation accompanying it. He has also shown both the applicability and the limitation of the quantum theory in relation to Röntgen radiation.

Barkla was elected a fellow of the Royal Society in 1912. On 19 January 1914 he was elected a fellow of the Royal Society of Edinburgh. He was proposed by Cargill Gilston Knott, George Alexander Carse, Sir Edmund Taylor Whittaker, and Sir Thomas Hudson Beare. Details of Barkla's scientific work appears in his obituary, written by C T R Wilson, which appeared an the Royal Society of Edinburgh Year Book 1946, 17-18. 

The greatest honour given to Barkla was the award of a Nobel Prize for Physics in 1917:-

... for his discovery of the characteristic X-radiation of the elements.

The Nobel Prize in Physics 1917 was announced on 12 November 1918. A Gullstrand from the Nobel Committee for Physics of the Royal Swedish Academy of Sciences addressed Barkla in a speech at the banquet following the presentation in Stockholm on 1 June 1920 [4]:-

Professor Barkla! Before it was known that the nature of X-rays is the same as that of light, with a difference only in wave-length, you had found a form of polarization of those rays, and by your investigation of their absorption you had developed a form of spectroscopy, before it was known that there is a spectrum in the real sense of the word. You discovered a kind of secondary X-radiation that is independent of the chemical constitution, but characteristic of the element, and this characteristic X-radiation, now known as a line spectrum, has proved a phenomenon of fundamental importance.

In his reply Barkla stressed the importance of the award:-

The Nobel Prize is without doubt the highest honour, the most coveted honour, which can be bestowed on a Scientist. There are of course very obvious reasons for this. It would be affectation on my part not to mention the monetary value of the prize; this is especially important at the present time, when rewards are given more than ever to those who can show the immediate practical results of their labours, and when those who seek knowledge and search after new methods are in danger of being left to pursue their course unrecognised and unheeded. Not only is the reward of great assistance to the scientist whose remuneration is slight; it impresses on 'the man in the street' as nothing else could, the importance of work being accomplished in a sphere far removed from his own. Further, the majority of honours are awarded with a definite and intentional bias in favour of scientists of certain nationality, whereas the Nobel awards are made without consideration either of social position or of nationality.

Further details of Barkla's life and research achievements are given in the obituary written by Whittaker and Born which appeared in The Scotsman on Tuesday, 24 October 1944. 

Barkla was a member of the Edinburgh Mathematical Society. He joined the Society in December 1913 soon after he arrived in Edinburgh to take up his appointment as Professor of Natural Philosophy.

As to Barkla's character we quote from [3] (see also [1]):-

1. Biography in Dictionary of Scientific Biography (New York 1970-1990). 
   http://www.encyclopedia.com/doc/1G2-2830900268.html
2. Biography in Encyclopaedia Britannica. 
   http://www.britannica.com/EBchecked/topic/53462/Charles-Glover-Barkla
3. Biography by Isobel Falconer, in Dictionary of National Biography (Oxford, 2004).
4. Charles Glover Barkla, Nobel Lectures, Physics 1901-1921 (Elsevier Publishing Company, Amsterdam, 1967).
5. C T R Wilson, Charles Glover Barkla, RSE Year Book 1946, 17-1