"The prosecution of research at low temperatures approaching the zero of absolute temperature is attended with difficulties and dangers of no ordinary kind," Dewar wrote. There existed "no recorded experience to guide us...[in] storing and manipulating exceedingly volatile liquids like liquid oxygen and liquid air," which exploded ordinary glass vessels, caused metals to freeze and shatter, and exceeded the measuring capacities of instruments. His rather exalted language couched the difficult though ordinary problem of figuring out how to store low-temperature liquefied gases, and it reflected Dewar's increasingly heroic view of himself as engaged in a great struggle for knowledge.
The solution to the storage problem came to him in 1892, and it harked back to experiments he had begun twenty years earlier, on making vacuums. "Exhausting" the air between the outer and inner walls of a container, he found that the inner vessel could then readily contain the corrosive and volatile liquefied oxygen and could hold it in quantities large enough for a series of experiments. Perfecting this device took him a year and innumerable tries, during which he determined that coating the inside of the flask with a thin layer of silver or mercury reduced loss by radiation by a factor of 13. Dewar presented the first perfected flask to the Prince of Wales at a public meeting at the Royal Institution. The "cryostatic devices" that Dewar produced for his low-temperature work were avidly sought and adopted by everyone else in the field and became known as "dewars." A "magnificent invention," Kamerlingh Onnes called the dewar, "the most important appliance for operating at extremely low temperatures."
The commercial version came about almost by accident: Dewar was having difficulty obtaining proper glass for his cryostats and commissioned a glass blower in Germany to make some for him; that man put his baby's milk in one of the flasks overnight and found that the milk was still warm in the morning. He took the idea of a "Thermos Flasche" to a manufacturer, and an everyday item was born.
Dewar's reticence to patent his own invention has been attributed by some historians to his mingling with the upper crust of London society, whom he might have believed likely to frown on any attempt at commercialism by a serious scientific researcher. But Lord Kelvin was not above obtaining patents for his work, and no scientist was held in greater respect by the elite. Perhaps Dewar did not realize that something designed for use at—200°C would be useful outside the land of Frigor.
In any event, with dewars in hand, their inventor could almost taste the triumph that lay ahead, the true liquefaction of hydrogen; by 1894, it seemed just inches from his grasp.
Seventeen years after Cailletet and Pictet had announced the first, fractional liquefactions of nitrogen and oxygen, Dewar in 1894 stood at the brink of the great mountain range he and everyone else in the field thought was the most important barrier between them and the cold pole of absolute zero. That mountain was the challenge of liquefying hydrogen in quantity. Dewar was working to remove the last kinks and problems from his materials and machinery, since every speck of impurity in the gas supply or minute defect in the seals of the apparatus, or in its ability to maintain pressure, or in the vacuum insulation of the cryostats, could spoil the experiment and result in failure. Although he was not the sort of man who shared his frustrations, the entire scientific community of Great Britain knew that he was on the verge of his greatest triumph and that it might be only a few months before he reached his goal of 20 cubic centimeters of hydrogen boiling quietly in a vacuum vessel, at a mere two dozen degrees above absolute zero.
Repeatedly during the 1880s and early 1890s, while proceeding with his scientific inquiries in the low-temperature region, Dewar would extract from them effects that delighted lecture audiences. The pressure he put on himself to invent better and more startling demonstrations multiplied as the geographic explorers returned from their quests to give popular lectures at other institutions. The Royal Institution's Friday Nighters were treated to having the amphitheater darkened and watching Dewar rub a cotton-wool sponge soaked in liquid air over a large vacuum vessel containing mercury or iodine vapor; just a touch produced luminous glows in the vessel, or bright flashes of light that enabled the audience to see its shape. A bath in liquid oxygen turned oxides and sulfides bright orange, chrome yellow, or metallic white, or made them lose their color. A multicolored soap film, suspended above a flask of liquid air, froze in the dense gas given off, preserving its sequence of colors. Tracing a line of liquid air on a band of India rubber, Dewar made the rubber alternately contract and expand in response to his drawing. He accompanied such magical demonstrations with erudite patter—the changed colors of the oxides and sulfides revealing "that the specific absorption of many substances undergoes great changes at the temperature of minus one hundred and ninety degrees centi grade"—but it was the visual displays that stayed in the minds of audience members.
As a connoisseur of Dewar's lectures later wrote, the showy demonstrations were of interest to "those in his audience who knew what they were witnessing, whilst the rest of his audience was interested much as it might have been by conjuring tricks." Magic shows were at the height of their popularity in Victorian music halls just then. Though the Friday Nighters loved Dewar's showmanship, the more scientifically learned in the audience did not, in general, approve: the theatrics smacked overmuch of magic and illusion, drew attention to the experimenter instead of to the advance of science, and strongly and adversely altered the expectation of lecture audiences for other scientists' reports of their work. Worse, the grandstanding became intertwined with Dewar's growing sense of the importance of his own position and research, his autocratic behavior, and his unwillingness to put enough effort into maintaining good relations with colleagues among the scientific elite.
When Dewar was awarded the Royal Society's Rumford Medal in 1894 for his dewars, most English scientists applauded, but a few grumbled under their breath at the unfairness of it—could not the committee have also included Fleming in the citation? In Krakow, Olszewski seethed at the announcement. It seemed to him that Dewar had simply copied the metal apparatus he had perfected in 1889 to 1890. Olszewski based his belief on having published a report of the work in a French-language journal in 1890, a copy of which he had sent to Dewar. A long illness in 1892 had made it difficult for Olszewski to leave his laboratory building, and he had simply moved into it his bed and belongings; since he was wifeless and childless, the change in accommodations isolated him all the more and induced in him a touch too much contemplation of his own successes, failures, slights, and annoyances.
Olszewski became convinced that Dewar had deliberately ignored his work, that "the experiments of Professor Dewar are merely the repetition and confirmation of [my] researches," and that "the first apparatus serving to produce large quantities of the liquefied so-called permanent gases ... was constructed by me." Olszewski further charged that the Dewar-Fleming work on the magnetic properties of materials at low temperatures was just a repetition and slight extension of that previously done by Clausius, Cailletet, and von Wróblewski. These charges were printed in the February 1895 issue of the English-language journal Philosophical Magazine, and they appeared in that venue as one result of the growing rift between Dewar and other leading lights of British science.
The bad blood may have dated back to 1877, when the chemist William Ramsay had applied for the chair at the Royal Institution that was shortly won by Dewar. Ramsay was a fellow Scot and was similarly trained; his later successes, including a Nobel Prize in 1904, attest to his strength as a chemist. It is likely that he was denied the Royal Institution position only because he was ten years younger than Dewar. Intimates of Ramsay recall he took the defeat well enough, and he was also turned down for other chairs before settling in at the University of London—but Dewar appears to have never forgiven Ramsay for the effrontery of applying for a chair that he believed was his almost by divine right.
Then there was Lord Rayleigh, born John William Strutt, who was a neighbor of Dewar's, occupying the upstairs laboratory at
the Royal Institution. Early in 1894 Rayleigh began to look into an anomaly in the density of nitrogen; within the year, this examination led Rayleigh and Ramsay to the discovery of a new gas, eventually named argon. The day after their first, brief announcement—really a report on work in progress—was made, and again a few days later, Dewar cast doubt on their work in letters to the London Times, claiming that what they had discovered might only be an isotope of nitrogen. These letters bothered Rayleigh—he didn't expect to be publicly sapped by a colleague when the information (and doubts) could as easily have been conveyed privately—but Ramsay ignored them and continued on. Dewar pretended to do so as well, even corresponding with Ramsay about his progress in isolating the as-yet-unnamed gas.
Morris Travers, then Ramsay's assistant, and a brilliant chemist and tinkerer himself, later wrote of this moment that Dewar misinterpreted his own findings and missed discovering argon, concluding that "if he had been skilled on the chemical side, he could hardly have missed krypton, not to speak of neon and xenon," the other noble (inert) gases Ramsay and Travers would discover in ensuing years. In Travers's view, Dewar's strength was the "engineering" aspect of chemistry, not analysis. More important for the story of research into the low-temperature regions, Travers deprecated Dewar's insistence on "a policy of secrecy" about the exact configuration of his apparatus for liquefying air; for most of the early 1890s, that secrecy kept others from being more active competitors in the race to liquefy hydrogen, permitting Dewar to maintain the lead position.
The Ramsay-Rayleigh research continued through the late summer and fall of 1894, when there appeared in Chemical News letters signed by a pseudonymous "Suum Cuique," suggesting that Dewar, rather than Ramsay, had first alerted Rayleigh to the work of Henry Cavendish, who nearly a hundred years earlier had noted the anomaly in nitrogen. It was thought that Dewar, or someone acting for Dewar, was Suum Cuique, but this was never proved.
However, when it came time for Ramsay and Rayleigh to choose a chemist to liquefy argon, as part of a group of people examining its various qualities, Ramsay chose Olszewski rather than Dewar, and Rayleigh could no longer object to this passing over of his neighbor in favor of a distant collaborator. The choice of Olszewski was not mere spite, according to Travers: Ramsay knew Olszewski had trained under Bunsen, as he himself had done, and he had checked Olszewski's results on other matters, which were good; moreover, Olszewski used a gas thermometer for his readings, while Dewar used indirect measuring instruments that Ramsay considered unreliable.
While Olszewski and Ramsay were in contact about the argon research—which Olszewski successfully accomplished—the Pole told his new collaborator about his own long-simmering annoyance at Dewar. In late 1894 Ramsay arranged for Olszewski to publish two articles, one a "Claim for Priority" in Nature in January 1895, and a second in the February 1895 issue of the Philosophical Magazine, and to announce a forthcoming English-language publication of Olszewski's collected research articles.
Dewar struck back immediately, and with great force, in the next issue of the Philosophical Magazine:
It is usually assumed that if a scientific man has a grievance on some question of priority, he speaks out boldly at or about the time when his discovery is being appropriated.... Professor Olszewski prefers to nurse his complaints for four years and then to bring them out simultaneously in two English scientific journals. The result, I am afraid, will be grievously disappointing....We want in this country a reprint of the splendid papers of the late Professor Wroblewski. Until this is done it will be impossible for the scientific public to decide on many of Professor Olszewski's claims for priority.
Dewar then went on to show that one part of Olszewski's apparatus had been taken from an 1878 design by Pictet and that another part had been borrowed from Dewar's own 1886 device, a virtual blueprint of which he had attached to his 1886 article on meteorites. Since that article had been on a seemingly unrelated subject, Olszewski might be excused for not having spotted it; in fact, Onnes had also missed the article—he later wrote that he had overlooked it because no report of the paper showed up in the Beiblätter journal of abstracts. But Dewar would not forgive Olszewski for missing his meteorite paper. He also quoted Olszewski against himself, citing other articles in which the Pole had described using glass rather than metal containers up through 1890, and an instance where Olszewski had cited the results of an 1892 Dewar and Liveing article in one of his own reports. Dewar concluded that Olszewski's claims for priority were "fantastic and unfounded."
At this time Dewar also refused to permit Pictet to visit his low-temperature laboratory, in order, he later wrote, "to prevent any further recriminations," and he decided to initiate a correspondence with Heike Kamerlingh Onnes.
In a restrained but determined handwritten note to the Dutch professor in 1895, Dewar wrote that there were only three people in the world who could "know the worries ... of low temperature research and who can appreciate [that] such work requires a long apprenticeship of a very trying and disheartening kind." He conveyed his upset at Olszewski's articles, which gave to the public the ludicrous idea that liquefaction of gases was easy; Onnes, of all men, would know this was absurd. "The fact is I never learnt anything in the way of manipulation of liquid gases from Prof. Olszewski," Dewar charged. Trying to achieve common ground with Onnes, Dewar confided that his two professorships and their attendant details were getting in the way of his liquefaction research: "If I had nothing else to do but low temperature work I like you might get on faster." He pledged that from here on in, he would do nothing that did not add "lustre to the dignity of science."
Hardly. Not content to leave well enough alone, in an article printed a month after the first salvo at Olszewski, Dewar digressed from the subject at hand to slam the Pole's English sponsor:
One can only wonder at the meagre additions to knowledge that in our time are unhesitatingly brought forward as original, and more especially that scientific men could be got to give them any currency in this country. Such persons should read the late Professor Wroblewski's pamphlet, entitled "Comment l'air a été liquefié" [How the Air Was Liquefied], and make themselves generally acquainted with the work of this most remarkable man, before coming to hasty conclusions on claims of priority brought forward by his some-time colleague.
There could be no doubt about whom Dewar referred to, even if he did not name Ramsay. This unnecessary bashing of a fellow member of the Royal Society, one of the most distinguished scientists of his day, would shortly have repercussions that Dewar could not have imagined, and that would directly influence the forthcoming stages of the race for the ultimate pole of Frigor.
9. Rare and Common Gases
BY 1895 WILLIAM THOMSON HAD BECOME Baron Kelvin of Largs, Great Britain's grand old man of heat and cold, though at seventy he was far from retired. The early experiments he and Joule had conducted together had suffered the usual fate at the hands of time: younger scientists took them for granted and did not reexamine them for clues to further research. The Joule-Thomson effect—the lowering of temperature attendant on the rapid expansion of highly pressurized gases into less pressurized environments through a porous plug—had not attracted much attention from pure-science researchers in the forty years between 1855 and 1895. But in a rare reversal of precedence, researchers with commercial goals in mind paid close attention to the Joule-Thomson effect, as was evident from the near-simultaneous filings of patents for gas-liquefaction processes based on Joule-Thomson expansion in the late spring of 1895 by Carl Linde and William Hampson, which led directly to the first large-scale commercial utilization of the products of the ultracold.
Linde's patent filing was the culmination of nearly twenty years' work, during which his company had sold more than a thousand refrigeration systems and had established its own research laboratory to investigate the commercial potential of newer liquefaction techniques. These pursuits led Linde to combine in a single machine the use of Joule-Thomson expansion, a heat excha
nge principle, and an engine earlier invented by Siemens. Linde aimed at the commercial manufacture of liquefied oxygen and nitrogen, respectively for use in steel making and as agricultural fertilizer.
William Hampson, who patented a similar machine at almost the same moment in time, was a curiosity in Great Britain's scientific circles. Though he had been schooled at Oxford and had trained as a barrister at the Inner Temple, his name never showed up on any lists of lawyers, and his activities before 1895 have remained obscure. They can only be inferred from his later pursuits. He qualified as a medical practitioner and ran the x-ray and electrical departments of St. John's Hospitals in Leicester Square; he also invented electrical devices for muscular stimulation, and he wrote popular science books and an economics tract warning against the use of credit. Hampson came up with his own design for a "regenerative" machine for producing lowered temperatures, based on Joule-Thomson cooling and an adaptation of Pictet's cascade methodology; he was awarded a patent in May 1895, two weeks before Linde. Ralph G. Scurlock, a historian of cryogenics, puts the feat in context by pointing out that "Hampson with his limited facilities was able to invent and develop a compact air liquefier which had a mechanical elegance and simplicity which made Dewar's efforts seem crude and clumsy by comparison." Shortly, Hampson entered into a commercial partnership with Brin's Oxygen Company to produce liquid oxygen.
The efficacy of what came to be called the Linde-Hampson liquefaction process was so evident that pure researchers as well as commercially minded ones immediately sought to adopt the new process, either by purchasing a machine or by using the underlying principles to develop their own versions. Kamerlingh Onnes, for instance, bought a Linde machine as soon as it was available. And in Great Britain, Sir William Ramsay asked Hampson if he could borrow one, because he couldn't obtain any liquid air from James Dewar. Ramsay and Dewar were at loggerheads again. In December 1895, Dewar told a meeting of the Fellows at the Royal Society about his progress on hydrogen, and Ramsay rose to suggest—once more—that Olszewski had already liquefied the gas. An angry Dewar dared Ramsay to produce proof. At the next meeting, Ramsay had to admit that in the interim he had received a letter from Olszewski, denying having obtained hydrogen liquid from the static form of the gas. Dewar then published his account of the controversy, further humiliating Ramsay.
Absolute Zero and the Conquest of Cold Page 16
