Wegener, who had joined the International Aeronautical Federation and been certified as a pilot in ballooning, used these flights in September 1909 not just to assist Richarz but to adjust and improve a balloon theodolite of his own design for finding positions while in motion, something he had been working on mentally ever since his record-breaking flight with his brother Kurt in 1906.
While enjoying these aerial excursions, he was still deeply immersed in work on the Danmark material. He had finally finished the aerology, the only part he cared about very deeply, and his colleague Lüdeling was proceeding well with the electrical measurements. He still had the magnetic work to account for and finally was on the verge of talking Walter Brückmann (1878–1960), a geophysicist acquaintance from Berlin, into taking them on in return for publication credit. He wrote to the Danmark Committee that the negotiations were proceeding well. This, of course, was a means of “off-loading” this work and of speeding up the process of getting out from under the expedition work.69 The expedition work was both psychologically and intellectually draining for him. He desperately needed the stipend being paid him to finish the work, but, of course, if he finished the work, the stipend would end. It was, nevertheless, not just advantageous but really necessary for him to get free of all of this as soon as possible.
The theoretical development of his ideas on the physics of the atmosphere, forced on him by his desire to catch up with the work that had been done while he was in Greenland and by the necessity to give lectures at Marburg, was inspiring and encouraging to him. He was getting back into a familiar routine, getting back to the world of books talking to other books, where he had lived most of his life. But even as he did so, his very divided feelings about being back in an entirely bookish and academic setting were becoming evident.
He would have to give lectures in the winter semester, now that he had committed himself to an academic career, and he chose to offer a single course entitled “Astronomical-Geographical Position Finding for Explorers.”70 That this course should have come first, rather than astronomy or meteorology (in which he had actually habilitated), may seem odd, but there was a reason for it.
Antarctica?
However strong his impulse to have an ordinary academic career, sit at a desk, please his parents, and make a success as a university scientist, he was anxious to get back into the field. Even as he published his papers (or sent them off to Aßmann—he had written so many that spring that some would not be published for another full year) and announced lectures for the fall, he was in the process of applying to be part of a proposed 1911 German expedition to Antarctica to be led by Wilhelm Filchner (1871–1957).
Filchner was a military cartographer who had led an expedition to Tibet and one to Russia, and he was extraordinarily well placed, as an aide to the German General Staff, to assemble both military and civilian patronage in Berlin and elsewhere. He very much wanted to lead an expedition to Antarctica, even though he had no polar experience whatever. There is an interesting historical sidelight here: a contest between the supporters of Drygalski and those who sided with Filchner, with the sense among the partisans of the latter that Drygalski’s Gauss Expedition had produced very little in terms of national honor and “names on the map,” for all the scientific results collected. Most of the staff for this new expedition, including the scientists, had been long since chosen: Filchner had made most of these decisions in the spring of 1908 while Wegener was still in Greenland. There was as yet no firm date for departure of the expedition to Antarctica, and in the meantime there was a planned pre-expedition to Spitzbergen, in the winter of 1910, so that the members of the expedition might acquire some polar experience. Of course, Filchner might have acquired polar experience by hiring some of the members of the Drygalski expedition, but the controversy, to which he was a party, clearly prevented this.
Filchner’s expedition was certainly well financed. He had purchased a ship, the Bjorn, and rechristened it the Deutschland. The expedition had the endorsement of Shackleton, who had just returned from his first expedition to Antarctica, and of Roald Amundsen. Wegener’s chances of getting on the expedition were very slim. Like most expedition leaders, Filchner was reluctant to take anyone along with more experience than himself—meaning, in this case, anyone with any polar experience at all. Moreover, as someone who had explored in Greenland, Wegener was viewed as one of the “Drygalski people.” Still, Wegener reasoned, he had made it onto the Danmark Expedition at the last moment; maybe he could finesse this again.
Wegener, of course, was dreaming of Antarctica while still in Greenland in 1906–1908. Now, with the very public dispute between Robert Peary (1856–1920) and Frederick Cook (1865–1940), both of whom claimed to have reached the North Pole in 1909, the excitement about Antarctica was nearing its peak. Nation after nation was throwing money at Antarctic explorers, not least for the possibility of claiming these lands as part of their empire.71 These include the Shackleton expedition from Great Britain in 1908–1909 and proposed expeditions by Japan, Great Britain (Scott), Australia (Mawson), Amundsen’s (as yet well concealed) Norwegian team, and Filchner himself. Germany, always a latecomer in the imperial sweepstakes, was late getting started here as well, and this was all the more reason for Wegener to believe that he could attach himself at the last minute to this expedition.
Running Away to Sea
Life in Marburg, pleasant enough and filled with his relentless pursuit of his own scientific work, was nevertheless beginning to seem confining before he had even begun to teach. Ballooning was exciting and never without danger, but Wegener was an explorer, not a thrill seeker, and his balloon trips were not really “expedition travel.” He had returned from military maneuvers in August and September in top physical condition and wanted very much to be out of doors even as his work called him constantly to his desk.
It was in this restless frame of mind in mid-October, with the looming of the Michaelis semester only weeks away, that he decided to postpone by a few months his entry into teaching and decided instead to “go to sea.” The International Commission for Scientific Aerology was about to launch a coordinated aerological experiment at sea. Hergesell and Teisserenc de Bort had been studying the global atmospheric circulation and had come to absolutely contrary positions on the character of the trade winds, especially at higher altitudes. These were two leading figures in the study of the structure of the atmosphere, and one of them had to be wrong; this experiment would determine which one.
The question was absorbing and of immediate interest to Wegener. While he had been in Greenland, Hergesell and Teisserenc de Bort had made observations in both the tropical Atlantic and the Mediterranean. These had established (as Wegener had remarked in Hamburg in the fall of 1908) that the trade winds were a shallow frictional layer above the boundary layer (300–500 meters) and below 1,500 meters, and within this altitude range, these two senior investigators had found a complicated structure of temperature and humidity with very strong inversions. This was, in Wegener’s eyes, his “1,500-meter layer.”
The problem that the “Experiment at Sea” was intended to solve was the layering of the atmosphere (and the wind direction) up to an altitude of 4 kilometers (2.5 miles). Hergesell championed the idea of “counter-trade winds” blowing in the opposite direction from the trades at greater altitude, and Teisserenc de Bort disagreed. What excited Wegener about this debate was the possibility, of which he was already himself convinced, that the issue had been misconstrued by these famous principals: the issue was not the wind direction and its constancy in some direction or another, but the constancy of the layers within which these winds blow. For Wegener, as opposed to his senior colleagues, this was a problem to be solved by thermodynamics, not dynamics—it was about the permanent structure of the atmosphere in the vertical direction, not its motion horizontally.72 This debate was one, therefore, in which he very much wanted to participate and in which he felt he could play some sort of a role.
In the ex
periment, in addition to dedicated research vessels (mostly the yachts of wealthy patrons), the idea was to put a number of aerologists on commercial freighters as supernumeraries, from which vantage they could make pilot balloon observations of the direction and velocity of the wind. Wegener had applied to Hergesell to be part of this and been accepted into the experiment, scheduled to run from mid-November to mid-January. Subsistence allowances and equipment were to be provided for the observer.
Of course, nothing happened in Wegener’s life without a list of official permissions. On 1 November 1909 Wegener wrote to the Danmark Committee for permission to set aside his contract and the work on the Danmark Expedition results for two months and push his remaining stipend forward for two months. He had, the week before, written to the committee to confirm that Brückmann would take over the magnetic observations, and with this gesture of good faith in place, the required permission in this quarter was immediately forthcoming.73
Wegener had also to obtain permission from his university to postpone the beginning of his winter semester lectures until the end of January.74 He also had to ask the dean (the geologist Emmanuel Kayser) to intercede on his behalf with his regimental commander, to excuse him from yet another extended session of military training and maneuvers scheduled to run from February until mid-April 1910.
Wegener asked Kayser to tell the military commander that “he could not be spared” for the maneuvers, and Kayser, who appears to have liked Wegener a good deal, was glad to oblige.75 Then, also in early November, Wegener wrote to Köppen to tell him of his plans to take part in the experiment. Wegener had not been much in correspondence with Köppen since the previous year, though he had used Köppen’s ideas about the advance of meteorology in his inaugural lecture a few months previously. Wegener was to travel aboard a Lloyd steamer, the Tübingen, from Bremerhaven to Montevideo and then to Buenos Aires, by way of Madeira. The core of the experiment was to take place in the first half of December, when a broad range of observations would be made by many observers sending aloft pilot balloons from aboard ships to analyze the airstream of the trade winds at various altitudes.
Still in the midst of his preparations for sailing on the Tübingen, Wegener received a letter from Köppen including a recent paper and some information on recent advances in aeronautics. Most interesting to Wegener was the information that Köppen provided on the distribution of inversions in the atmosphere up to 1,500 meters. Köppen had calculated the percentage of inversion, that is, the percentage of increases in ambient temperature at altitude, as a percentage of all raw measurements. Köppen’s figures showed frequency maxima for inversions between 700 and 900 meters (2,297–2,953 feet) and between 1,200 and 1,500 meters (3,937–4,921 feet). Wegener wrote to Köppen,
Of greatest interest to me were the investigations of inversions … here again these are typical upper surfaces of the cloud layers, namely those at 800 and 1500 m. I don’t know whether this is just my own idiosyncrasy, but everywhere I turn I stumble over these typical boundary surfaces! I believe additionally that an even greater maximum percentage will be recorded at the mean altitude of 39–42 hectometers (the level of a-cu [altocumulus]) when kite investigations eventually reach that altitude! … I’ve been going into this rather deeply and this idea seems to me to open an extremely useful perspective. In any case I have a great sack of [research] plans a few of which may hopefully be carried out by sufficiently ardent doctoral students.76
Wegener was indeed seeing these “typical layer boundaries” everywhere, as were many others at exactly this time. Wegener, however, was of his contemporaries the most convinced that these held the key to the structure of the atmosphere.
With permissions obtained, and once more with the prospect of an expedition, Wegener happily departed Marburg, but there were maddening delays. The original departure date of his steamship, 17 November, was postponed for ten days, and he found himself cooling his heels in Berlin with his parents. When he finally departed, the freighter dawdled on from Bremerhaven to Antwerp, where it was still sitting in port on 7 December, one week into the planned experiment. From Antwerp he wrote a laconic plea to the Danmark Committee to extend his contract forward yet another month.77
Finally under way and out of Europe, the freighter made port in Madeira on 15 December, and a very unhappy Alfred Wegener took the opportunity to write Christmas and New Year’s greetings to his parents. Things were not going well. There was too much wind for the balloons, and though they sent up one or two a day, they could follow them for only a short time before they vanished from sight. As his technical correspondence (before the expedition began) shows, Wegener had thought from the beginning that the balloons were much too small to be followed easily, and this turned out to be the case. “I have written Hergesell about it. There you are—this is how we find out!”78 He also added sardonically, “I haven’t been seasick, though not from lack of opportunity.”79
As if the delays, the bad weather, and the failure of the observation program were not enough, he found out once under way that the ship would lay over in Buenos Aires for three weeks. “When I’ll get back, only the gods know … if I can’t find another ship, I can scarcely be back before mid-March. Since the end of the semester is March 2, I can begin to see that my lectures are for the present on hold.”80
The remainder of the trip—to Montevideo, to Buenos Aires, and the return—was a complete loss from the standpoint of scientific observation. There was, however, a good deal of time to think and write, and Wegener turned again to the problem (and the idea) of some sort of physical layer in the atmosphere, mentioned ever so briefly in his inaugural lecture at Marburg, a layer that would reside at an altitude of about 70 kilometers (43 miles). The general theme and intuition (long with him) that the atmosphere was riddled with poorly understood layers, and was not a thermodynamic continuum but a discontinuum, more and more occupied him as he stirred restlessly in his bunk on the returning freighter.
At least his worst fears were not realized: he managed to find another ship and was able to return to Marburg by mid-February, but with essentially nothing to show for three months of effort. Moreover, in his absence, the world (as was its wont) had moved along without him. Aßmann could not wait for Wegener’s return to solve his own staffing problems and had appointed Otto Tetens (1865–1945) as Berson’s replacement. Tetens was an astronomer and a photographer of repute (on the model of Adolf Marcuse, Wegener’s teacher at Berlin). He had been Kurt Wegener’s predecessor at Samoa and was working as an astronomer at the observatory at Kiel at the time of his appointment. He was in no sense a theoretician, but he was an experienced and skilled observer who, like Aßmann, was very interested in instrumentation and error correction. Tetens’s career shows “what might have been” for Wegener. Tetens was appointed to Lindenberg in 1909, by December 1910 he was awarded the title of professor, and from 1911 until Aßmann’s retirement in 1915 he was acting director of the observatory at Lindenberg. Unbeknownst to Wegener, Aßmann had been offering him a greater gift: not just that he should replace Berson, but that he should replace Aßmann himself!81
So Wegener was not to go to Lindenberg; he would remain in Marburg and teach—perhaps. Because of the lateness of his return from South America (two weeks before the end of the semester that had begun in November), no one had signed up for his course on position finding, so he conferred with students and informed Richarz that he would offer the course again in the winter of 1910–1911.82
Wegener’s Theory of Atmospheric Structure
With no teaching duties in the offing until summer semester (15 April), when he would offer a course of lectures in physics of the atmosphere, Wegener was free to pursue his increasingly comprehensive researches into this very topic. The central point of all his work was the layering of the atmosphere. It was to his intuition of discontinuity (as a key to structure) that he returned again and again. From this intuition, rapidly maturing into a conviction, Wegener made an increasingly bold series of spe
culations, based on slender but real empirical data, about the full height of the atmosphere and its behavior.
Near the end of February 1910, Wegener sent off to Aßmann a manuscript extending and developing the idea that somewhere between 70 and 80 kilometers was another major atmospheric discontinuity. This was an idea broached in his inaugural lectures at Marburg the previous May and developed in the published version of that lecture the previous November (1908). Wegener had worked on this in his ship cabin on the return from Buenos Aires, having no data to work up from this fruitless voyage. He entitled the paper “Über eine neue fundamentale Schichtgrenze der Erdatmosphäre” (On a new fundamental layer boundary in Earth’s atmosphere), certainly the most ambitious claim he had made thus far.83 It is also a remarkably novel and comprehensive approach to an old problem concerning the optical properties of the atmosphere, in which Wegener came very close to a major discovery.
It had been long established that there was a rather sharp boundary, the “twilight limit,” between that part of the atmosphere capable of reflecting diffuse light and the layer above it, no longer optically active, and estimated by many observers to occur at about 70 kilometers. Yet because the transition from light to shadow is continuous, it would seem impossible to say with any certainty that a specific layer boundary existed, but only some sort of transition zone. On the latter side of the argument was the evidence of the “noctilucent clouds” injected into the atmosphere by Krakatoa in 1883 to an altitude measured at 83 kilometers (52 miles). In this case, light was reflected back to Earth from a height 13 kilometers (8 miles) greater than the current estimate of the “twilight boundary” layer.
Wegener had argued in his inaugural lecture at Marburg that the height of the Krakatoa clouds was precisely evidence of a sharp boundary layer—in this case, one broken through by the volcanic dust cloud, in the same way that a cumulus cloud breaks through an atmospheric layer and causes a local inversion. More importantly, however, Wegener believed himself in possession of evidence providing “an astonishing confirmation” of what had been only a supposition. The evidence in question was that provided by a consideration of the chemical composition of the atmosphere at different altitudes: “in what follows arguments will be set out which will indeed make this view [of a discontinuity at 70 kilometers] so probable that, I believe, scarcely any ground for doubt will remain.”84
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