查尔斯·格洛弗·巴克拉Charles Glover Barkla

查尔斯·格洛弗·巴克拉的父亲是弗瑞兹·约翰 Martin Barkla，阿特拉斯化学公司的秘书，母亲是Sarah 巴克拉。巴克拉在利物浦学院学习，然后在1894年，在获得Bibby和郡议会奖学金后，他进入利物浦大学学院，当时是曼彻斯特维多利亚大学的一部分。在那里，他在Oliver Lodge的指导下学习数学和物理学，于1898年以物理学一等荣誉学位毕业，并在接下来的一年获得了硕士学位。然后，在1899年，他去了剑桥大学三一学院，但一年后转到了剑桥大学国王学院。这不是出于学术原因，而是他的主要消遣是唱歌——他有一副强有力的男中音嗓音——这一转学使他能够在1901-1902年间加入国王学院教堂合唱团。在剑桥，巴克拉在J J Thomson的指导下在卡文迪什实验室工作。Falconer写道[3]：-

巴克拉对Thomson产生了极大的钦佩，回忆说：‘我觉得我写的论文是给他读的：别人的欣赏是次要的。他的兴趣和他关于这个主题及相关的出版物是我最大的灵感。’

1902年，巴克拉被任命为利物浦的Oliver Lodge研究员，后来成为物理学助理讲师。1907年，他成为利物浦的高级电学物理学讲师，但两年后被任命为伦敦大学国王学院的Wheatstone物理学教授。四年后，即1913年，他被任命为爱丁堡大学自然哲学讲席。这在1913年7月9日星期三的The Scotsman中报道：-

新爱丁堡教授

昨天下午，爱丁堡大学的赞助人任命了巴克拉教授，目前是伦敦大学国王学院的Wheatstone物理学教授，担任爱丁堡大学自然哲学讲席，该职位因J G MacGregor教授去世而空缺。巴克拉教授是利物浦（当时是维多利亚大学的一部分）和剑桥的毕业生。他曾是伯明翰的校长Sir Oliver Lodge的学生，当时是利物浦大学学院的物理学教授，他称新当选的教授是他在利物浦最有能力的学生。在利物浦，他获得了Bibby奖学金和Oliver Lodge奖学金等多项荣誉，以及为期三年的1851展览奖学金（比通常多一年）。在剑桥大学国王学院完成课程并毕业后，他成为物理学演示者，后来在他旧学院（现利物浦大学）担任高级电学讲师，他是该校的D.Sc.，以及B.Sc.和M.Sc.，直到1909年当选到目前的职位。他为北英格兰大学做了很多考试工作，在原创研究中，X射线和伦琴射线一直是他研究的主要主题和发表作品的主题。作为一名教师，他非常成功。在欧洲大陆，他的工作也得到了Solvay国际研究所（布鲁塞尔）的认可，去年他的伦琴辐射研究工作获得了2500法郎的资助；而上个月，德国物理学会邀请他在明年9月于维也纳举行的科学和医学大会上作为外国学者进行年度讲座。他的主题将是“伦琴辐射”。1912年，他获得了皇家学会会士。

Falconer写道[3]：-

巴克拉在爱丁堡大学设立纯科学荣誉学位以及发展物理学荣誉学院方面发挥了重要作用，他的领导风格效仿了卡文迪许实验室的汤姆孙。

1907年，巴克拉与杰西·道格拉斯的约翰·T·考威尔的長女玛丽·埃斯特·考威尔结婚，他是马恩岛的税务总长；他们有两个儿子和一个女儿。他们最小的儿子，空军上尉Michael Barkla，是一位才华横溢的医学学者，但不幸于1943年在北非阵亡。

在[4]中详细描述了巴克拉的研究贡献。以下提供一个概述：-

巴克拉的早期研究涉及电波沿导线的速度，但1902年他开始研究伦琴辐射，这几乎占据了他的一生。他发现元素特有的均匀辐射，表明这些元素在X射线中具有其特征线状谱，并且他首次表明次级发射有两种：一种由未改变的散射X射线组成，另一种是特定物质特有的荧光辐射。他发现了X射线的偏振，这一实验结果相当重要，因为它意味着X辐射可被视为与普通光类似。巴克拉在X射线的吸收和照相作用方面做出了宝贵贡献……他后来的工作证明了特征X辐射与伴随的微粒辐射之间的关系。他还展示了量子理论在伦琴辐射方面的适用性和局限性。

巴克拉于1912年当选为皇家学会会士。1914年1月19日，他当选为爱丁堡皇家学会会士。他的提名人是Cargill Gilston Knott、George Alexander Carse、埃德蒙·泰勒·惠特克和Thomas Hudson Beare爵士。巴克拉科学工作的详情见其讣告，由C T R Wilson撰写，发表于爱丁堡皇家学会 Year Book 1946，17-18页。
我们在THIS LINK给出一个版本

授予巴克拉的最大荣誉是1917年获得诺贝尔物理学奖：-

……因他发现元素的特征X射线。

1917年诺贝尔物理学奖于1918年11月12日公布。瑞典皇家科学院诺贝尔物理学委员会的A Gullstrand在1920年6月1日斯德哥尔摩颁奖后的宴会上发表演讲，向巴克拉致辞[4]：-

巴克拉！在人们知道X射线的性质与光相同、只是波长不同之前，您已经发现了这些射线的一种偏振形式，并且通过对它们吸收的研究，您已经发展出一种光谱学形式，而当时人们还不知道存在真正意义上的光谱。您发现了一种次级X射线辐射，它不依赖于化学组成，却是元素的特征，这种特征X射线辐射，现在被称为线状谱，已被证明是一种具有根本重要性的现象。

在答复中，巴克拉强调了该奖项的重要性：-

诺贝尔奖毫无疑问是能够授予一位科学家的最高荣誉，最令人向往的荣誉。当然，这有非常明显的原因。如果我不提及该奖的金钱价值，那就是做作；这一点在当前尤其重要，因为如今奖励比以往任何时候都更多地给予那些能够展示其劳动直接实际成果的人，而那些寻求知识、探索新方法的人则有被置于无人认可、无人理睬的境地之危险。奖励不仅对报酬微薄的科学家有极大帮助；它还以其他任何事物都无法做到的方式，让“街上的普通人”认识到在远离其自身的领域中正在完成的工作的重要性。此外，大多数荣誉的授予都带有明确且有意偏向某一国籍科学家的倾向，而诺贝尔奖的授予则不考虑社会地位或国籍。

关于巴克拉的生平与研究成果的更多细节，见埃德蒙·泰勒·惠特克和马克斯·玻恩撰写的讣告，该讣告发表于1944年10月24日星期二的The Scotsman。
我们在THIS LINK给出一个版本。

巴克拉是爱丁堡数学会的成员。他于1913年12月加入该学会，当时他刚到爱丁堡就任自然哲学教授不久。

关于巴克拉的性格，我们引用[3]中的话（另见[1]）：-

巴克拉身材高大，体格匀称，衣着保守，态度友善，尤其对孩子和蔼。他总是喜欢生活在乡村环境中。作为一名坚定的卫理公会教徒，他将科学研究视为“对上帝，即造物主的追寻的一部分”。

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, 9th 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.
We give a version at THIS LINK

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.
We give a version at THIS LINK

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]):-

Barkla was tall, well built, and conservative in dress, with a friendly manner, especially with children. He always preferred living in rural surroundings. A staunch Methodist, he saw scientific investigation as 'a part of the quest for God, the Creator'.