Nobel prizes and noble gases

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As the 2004 Nobel prizes are announced, Colin Russell examines the life and times of William Ramsay, who discovered the noble gases and won the coveted award in 1904.

The year 1904 was a good one for British science. Just a century ago Nobel prizes were awarded to two Britons, Lord Rayleigh received the prize for physics and William Ramsay the prize for chemistry. The award-winning research had much in common, and each man received recognition for his work leading to the discovery of the inert gases. We focus here on the chemical laureate.

William Ramsay was born in Glasgow on 2 October 1852. His father had worked in engineering and insurance, and his grandfather had been junior partner in a Glasgow firm of chemical manufacturers that has been credited with the discovery of the pigment Turnbull’s Blue and potassium dichromate. There was a long line of Ramsays with chemical interests, many being dyers in Scotland. William’s mother was Catherine Robertson, from a medical family in Edinburgh. He was the only child, born when his parents were around 40.

His mother was a committed Calvinist and hoped her son would enter the church ministry. Therefore, he entered Glasgow University to read Arts in 1866, at the tender age of 14. He had little taste for classical subjects, but had already become enthralled by chemistry, doing experiments at his home or that of a friend. So, from 1869, after lectures were over, he spent his afternoons at the laboratory of R R Tatlock, Glasgow city analyst. Next year he went to chemical lectures by Thomas Anderson and also those on physics by Lord Kelvin.

Other youthful interests included music and modern languages. These remained with him throughout life, his only complaint being that he never could cope with Gaelic. In 1869 he stayed with a cousin, Archibald Jolly, at Walls in Shetland, and there learned to swim and to manage a boat in all weathers. Next summer, at the same place, he was unaware of the new European war between France and Germany until he and a friend had walked some 25 miles to the town of Lerwick. This was serious news, for he had intended (as so many Britons at that time) to complete his chemical education in Germany. Bunsen’s laboratory at Heidelberg was his first choice, but in early 1871 he went instead to T?bingen, where study (under Rudolf Fittig) was cheaper. He resumed some work on platinammonium bases that he had started under Tatlock, but found the intense regime of lectures and laboratory too taxing even for his considerable energies. However, in 1872 he received his PhD for ’investigations on the toluic and nitrotoluic acids’. Within weeks he was back in Glasgow.

His first post was at Anderson’s College (’the Andersonian’), where he became assistant to G Bischof, professor of technical chemistry. Theirs was not a happy relationship, he had onerous responsibilities heaped on him by a boss who spoke no English. Fortunately Bischof was soon replaced by E W Mills, from whom Ramsay gained the first hints about the newly emerging physical chemistry. Also, at the Andersonian he first encountered Sprengel’s pump that was later to prove so useful in handling gases.

For all its merits, Anderson’s College lacked the status and appeal of the university, so Ramsay was glad to return there, this time to the department of chemistry. In 1874, he became tutorial assistant to John Ferguson, recently appointed as Thomas Anderson’s successor. Anderson had consigned to a cellar many samples of Dippel’s oil (a product from distillation of animal bones). They had been left undisturbed by Ferguson, an antiquarian by inclination, who regarded them as museum specimens. However, his assistant thought differently. Still an organic chemist at heart, Ramsay began to examine them, and isolated some pyridine bases, including picolines. He studied their pharmacological properties, and compared them with certain alkaloids, which on oxidation by potassium permanganate gave similar products to those from picolines. In 1876, using Sir James Dewar’s laboratory, Ramsay obtained a minute trace of pyridine by passing acetylene and hydrogen cyanide through a red-hot tube - arguably the first synthesis of the base. It was, sadly, recognisable only by smell!

Ramsay was also interested in geology; his uncle, Andrew C Ramsay, was to become a geologist of eminence and exerted a formative influence on his nephew. They had spent part of the summer of 1873 together, on field studies in the Rhine valley. William did some research on the loss of water by hydrates on heating, and gave a course on chemical geology in 1876. That was the year in which Ramsay’s chemistry was to take a radically new direction. At the British Association meeting in Glasgow he heard of some work on the new physical chemistry, including that by Osborne Reynolds on fluid flow and by James Thompson on liquid/vapour systems. It led to his own studies of the critical state.

After applying for several new posts without success, in 1880 he became professor of chemistry at University College, Bristol. His work included evening classes at Bristol and day courses on dyeing that compelled him to rise at 6 am in order to visit Frome, Trowbridge and Stroud, ’those benighted lands’ he ruefully called them. However, he was able to do some work with Sydney Young on liquid/vapour systems and their thermodynamics. An assistant for his first year was David Masson, later to achieve fame in the chemistry department at Melbourne, Australia.

In 1881, he became principal at Bristol. In anticipation of this promotion, he married Margaret Buchanan who came from a family of old friends in Glasgow. His biographers say very little about her, except that they were ’happily married’ and had two children. His appointment came at a time when finance was difficult and the college was so often in debt that he offered a reduction in his own salary. He took the lead in enlisting government aid for the smaller English University Colleges (though Manchester, Liverpool and Leeds stood grandly apart), and by 1889 a small grant was made in the budget of ?15 000.

Brighter opportunities lay ahead, and in 1887 a chemistry chair at University College London (UCL), became vacant by the resignation of Alexander Williamson. Ramsay was appointed as his successor. He encountered a dire legacy, this time not in the cellars alone but throughout the department. The laboratory was run-down, the stores neglected and a complete refurbishment was needed.

Amongst his colleagues at UCL were Edward Baly (who worked on gases at low temperatures, was an excellent glassblower and eventually became professor at Liverpool University), John Collie (whose organic chemistry was focused on -CO-CH₂-CO- compounds) and Morris Travers who became his closest colleague and eventual biographer. Apart from the reorganisation, life was not easy; there were disorderly classes of medical students to quell, and the usual daily tours of the laboratory where students were often encouraged to repeat experiments from the recent literature.

In research he worked with John Shields on liquid/vapour systems and studied variation of surface tension with temperature. But his most enduring work came with a study of the gases of the atmosphere.

This is where historical analysis is anything but easy. At the same time another researcher, Rayleigh, was working on the same lines, almost independently yet with teasingly vague occasional contacts between them. Defenders of each proclaimed one or other as champion. In essence, the facts are these.

John Strutt, the third Lord Rayleigh, had succeeded Clerk Maxwell in the chair of experimental physics at Cambridge University in 1879. From 1884, however, he conducted private research in a laboratory at his home in Terling, Essex. For some time he had been interested in getting accurate atomic weights for the elements, and called for a re-determination of densities of the principal gases. After working on oxygen he turned to nitrogen. He systematically removed other constituents from air (oxygen with red-hot copper) and measured the density of the residual gas, assumed to be pure nitrogen.

Uncertain of the accuracy he obtained he tried a method suggested by Vernon Harcourt and then passed on to him by Ramsay. The technique was to bubble air through ammonia solution and then pass it over hot copper (when the oxygen is reduced by the ammonia) before drying it, leaving nitrogen from two sources: air and ammonia. To his irritation (for he was a fastidiously accurate worker) he found a discrepancy of 2.3 mg, or one in 103, from the value for atmospheric nitrogen alone. Various impurities like hydrogen were ruled out, so Rayleigh wrote to Nature (September 1892), seeking advice from chemists. He received a reply from Ramsay who shared his bafflement. All he could suggest was that amine impurities in the ammonia might be responsible, or (even less likely) some kind of energy transfer from the ammonia could affect the balance.

Rayleigh then tried making ’chemical’ nitrogen in different ways, but always with the same result. By February 1894, the difference in densities of atmospheric and ’chemical’ nitrogen was established beyond doubt; it was published in a paper to the Royal Society in April.

At about this time Rayleigh heard from Dewar of an experiment by the English chemist Henry Cavendish as long ago as 1785. When a spark was passed through air with excess oxygen, oxides of nitrogen were formed. Cavendish had absorbed these in alkali, but a small bubble remained of highly unreactive gas. Rayleigh repeated the experiment and obtained about 1 ml of gas whose spark spectrum showed no trace of nitrogen. Here must be a new constituent of air.

Meanwhile, within five days of hearing Rayleigh’s paper to the Royal Society, Ramsay had begun to work on the same problem, . He used a different method to remove nitrogen. He heated magnesium in atmospheric nitrogen to see ’if there is anything over’. Within a month he was writing to Rayleigh, ’has it occurred to you that there is room for gaseous elements at the end of the first column of the periodic table?’ There was some verbal conversation between the two men on 24 May 1894, and on 4 August Ramsay wrote that he had isolated a new gas. Two days later Rayleigh replied that he, too, had met with success and suggested a joint paper, saying Ramsay’s results ’go further than mine’, but both were building on Rayleigh’s early work. Ramsay agreed.

Still nothing was published, but at the British Association meeting in Oxford (13 August 1894) Rayleigh gave a verbal report from Ramsay and himself to a packed audience. There were no abstracts, though there were some newspaper reports. Behind the scenes there was a good deal of scepticism and Rayleigh was uneasy, believing that it was better not to publish yet. A serious proposal that the new gas be called ’argon’ (from the Greek word for lazy) was later accompanied by more frivolous suggestions. A French sceptic suggested ’Oxfordgen’ and another wag christened it ’Mrs Harris’ (a missing woman in Dickens’ novel Martin Chuzzlewit).

In December that year Dewar nearly precipitated a crisis when he spoke to the Chemical Society on liquid air, concluding that ’chemical’ and atmospheric nitrogen boil at the same temperature. A report in the Times expressed surprise that Rayleigh and Ramsay still preferred to keep silent. In response to Rayleigh’s angry protests Dewar pointed out that these remarks were not his but the reporter’s.

While the press continued to be sceptical and probing, both investigators continued their work. Ramsay measured the density and specific heats of the new gas. From the specific heat ratio of 5/3 (similar to that of mercury), he concluded argon must be monatomic. Rayleigh was impressed by Ramsay’s skill as experimenter, but doubtful about some of his conclusions, especially over specific heats. On 23 September, Ramsay came to Terling for the weekend. It was agreed that he, the chemist, would work out the chemical properties of the new gas, though Rayleigh said ’but I don’t believe it has any!’

In January 1895, Ramsay read a paper on argon to the Royal Society; it was certainly his turn. He displayed a sealed tube full of the gas, to Rayleigh’s astonishment: ’I didn’t know you had as much as that’. Ramsay explained that though the tube did contain argon it had been largely evacuated to avoid losing valuable stock, and now it was indeed the new gas but at a very low pressure! The audience of course knew nothing of this.

By now he was hard on the track of isolating more new elements; Rayleigh had dropped out of this search because his interests as a physicist lay elsewhere. By 24 March 1895 Ramsay had discovered helium as a gas produced by the mineral cleveite (hitherto assumed to be nitrogen). He showed that it had the same spectrum as the gas identified on the sun by Frankland and Lockyer.

In 1898 he and Travers examined the least volatile portion of the newly available liquid air. They were rewarded by the discovery of no less than three newcomers, which they named krypton, neon and xenon. Following the isolation of radium salts by Marie Curie in the new century, Ramsay worked with Frederick Soddy on radium emanation and showed that helium was continually generated (as alpha-particles); and also obtained another gas, radon, whose spectrum he determined with Collie. Thus a complete new group of the periodic table had been identified and his triumph was complete.

After this he became an early convert to an electronic theory of valency (1908) and spent some time speculating on the possibility of transmutation. He wrote several historical works on chemistry and on history (despite admitting to Rayleigh ’I have not a historical memory’). His last years were engaged in travel to India and elsewhere, in problems of sewage disposal and (after 1914) in the role of chemistry in wartime. He retired in 1912 and died in 1916.

Ramsay received many honours including KCB in 1902 and the Nobel prize in 1904. He once admitted: ’There are some on whom honours seem to be heaped, and I am such a lucky man’. Yet he always was a controversial figure, never more so than in disputes about his priority over Rayleigh in discovering argon. There is little doubt that he did mediate Harcourt’s ideas to Rayleigh, but he was not the first (as he claimed) to draw attention to Cavendish’s crucial experiment. Rayleigh was certainly the first in the field and it is uncertain whether Ramsay observed the usual courtesy of gaining permission to enter another man?s research territory.

His relations with other London chemists are worthy of further study. He was not on speaking terms with Dewar at the Royal Institution whom he had mortally offended by wrongly denying his priority in the matter of hydrogen liquefaction. He seems to have had almost no contact with Sir Edward Frankland at South Kensington, except for being an occasional guest at Frankland?s grand dinner-parties at the Athenaeum. However, Frankland respected his work and when Ramsay was being considered for fellowship of the Royal Society in 1888 Frankland acted in his interest. He sent off an urgent letter to Armstrong for evidence to rebut the view of one (unnamed) member of the Royal Society Council that the proposal should be rejected ’on the ground that his work is bad and untrustworthy, and that this was the general opinion of chemists’. Despite this setback Ramsay was awarded FRS. However a more sympathetic, and accurate, assessment was provided by Alexander Crum Brown who, though disagreeing with some of Ramsay’s conclusions, nevertheless wrote ’We should esteem highly one who has not only the ingenuity needed to devise the methods and apparatus, but also the patience to carry out this long series of observations’. That unstoppable perseverance was probably Ramsay’s secret of success.

Acknowledgements

Colin Russell is emeritus professor in the department of history of science at the open University and affiliated research scholar at the department of history and philosophy, University of Cambridge. We are grateful to the Royal Society and to Juliet Frankland for permission to cite from letters.