Aßmann’s enthusiasm for Wegener was real and reflected in other ways as well. While Wegener was in Greenland, Aßmann, together with Hergesell, had advanced a new journal, Beiträge zur Physik der freien Atmosphäre, that would be concerned not just with meteorology but with atmospheric physics. This was a new and promising venue for Wegener, and he submitted to Aßmann the two manuscripts he had been working on: that on the layering of the atmosphere, and the associated work on the averaging of mean values, discussed above.
The first of these two manuscripts was acceptable as written, but the second involved Wegener in his first scientific controversy and his first priority fight. He had contacted Arthur Berson in an attempt to gain data on the altitude of the upper inversion in Africa, data that Berson (recently returned) had not even had a chance to publish yet, and with this request Wegener had informed him of the work on the averaging of values for atmospheric elements with kite flights of unequal altitude. Berson’s reply was combative: he denied that there was anything new in Wegener’s method, claiming that he had developed it himself and had used it since the 1890s. He also expressed a desire that he, and not Wegener (though the latter had been Aßmann’s wish), should present a proposal for international adoption at the meeting in Monaco in April.41
Wegener therefore inserted into the manuscript an agreed-upon statement that Berson had already employed the method, and he readily surrendered participation in the conference at Monaco, though hoping that Aßmann would make the presentation himself. Wegener insisted, however, that one had to accept the very great difference between using an empirical correction factor such as Berson’s (which was not new) and, on the other hand, providing an exact formulation of the scientific reasoning for the general adoption of such a correction factor, based on a comparison of several large data sets, some of which did not belong to Berson. It was the latter contribution that Wegener insisted was his own. He included this claim, with slightly different wording, in the preface to the paper itself, following the acknowledgment of Berson’s priority.42
Wegener does not seem to have been substantially diverted from his work plan by the scuffle; things were moving along quickly in Marburg: he had sent along a great packet of reprints of his papers and the required summaries of his credentials and professional accomplishments, along with his plans to teach. He proposed to give lectures in meteorology, astronomy, and cosmic physics. He would offer his Greenland aerology as his Habilitationschrift, that piece of writing beyond the dissertation that establishes the candidacy of a scholar to teach at the university level. He suggested as candidate topics for his Probevorlesung (a demonstration lecture to determine whether someone can actually teach) a lecture on new methods of investigation in meteorology, a lecture on new methods of position finding from a balloon (something to please Richarz), or perhaps a presentation of his historical work on the history of astronomy dating from his graduate school days. Finally, he offered a slide show of his investigations in Greenland.43
The appointment in Marburg was a virtual certainty. The dean of the faculty, the celebrated geologist Emanuel Kayser (1845–1927), had moved the appointment before the Marburg faculty at the earliest possible date and had scheduled the probationary lecture for 8 March. With this knowledge in hand, Wegener began to make his plans to move. He was soon informed that the Marburg faculty had elected to hear “Results and Aims of the New Methods of Aerological Investigation in Meteorology,” which Wegener then prepared on short notice. It contained mostly material he had written, and written again, though here he had a good chance to put his work in context, a context he could create himself.44
Defining His Place in Science: The “New Bezold”
Wegener’s “demonstration lecture” on 8 March shows how strong the historical instinct was in him. He had, after all, written a dissertation in the history of astronomy, albeit one of value to working astronomers. The research tradition of Berlin astronomy was embedded in an explicit historical context, and its pedagogy was also historical in structure. Berlin’s students were to understand not just the techniques of research but also the evolution of their field up to the time of their own work. This historical approach was characteristic of German astronomy and physics in general, but nowhere more strongly than in Berlin.
At the time of Wegener’s visit to Hamburg in November 1908, Wladimir Köppen had delivered an address on the evolution of meteorological science; this was published in January 1909 in Meteorologische Zeitschrift. Wegener took Köppen’s address as his starting point for his Marburg lecture. In the history of meteorology, Wegener declared, there is a rhythm of progress in which periods of introduction of new techniques alternate with the theoretical integration of the results of research. In meteorology there had been four such periods. The first was from 1650 to 1750, during which most of the meteorological instruments had been invented, and through which meteorology could be said to have originated. The second powerful impulse had been the development of climatological maps in the first half of the nineteenth century, which led to the emergence of climatology. The third new perspective emerged in the third quarter of the nineteenth century, with the foundation of synoptic meteorology and the development of the synoptic weather maps and their associated aids. Finally, the most recent revolution, barely twenty years old, consisted in the introduction of methods and aids that had given the science of meteorology a powerful impulse toward its true aim: its transformation into a physics of the atmosphere. These new methods, said Wegener, have been christened “aerology,” though this name, however well established, scarcely characterized the nature of the new branch of scientific research. This new period was still in the phase of discovery, of accumulation of facts: “the theoretical exploration of the insights thus gained has only succeeded in the most limited fashion, and the principal work in this area is reserved for the future.”45
Wegener’s timeline and capsule history gave a convergent series. With successive periods of 100, 50, 33, and 20 years (thus 1, 1/2, 1/3, and 1/5), Wegener suggested (numerically) that the completion of the next phase should occur within perhaps a decade. This also converged on the career of the lecturer, Wegener himself, whose work was poised between discovery of new facts and the first development of theory out of them.
Having located the history of meteorology in converging segments of time, Wegener went forward to locate the new work in space, as a complement to its temporal evolution. His associated figure, a “complete profile of the atmosphere,” is an extremely important datum in understanding Wegener’s concept of his own future work and career, laid out here before his audience.
Wegener began his account of the atmosphere at the outer limits, the extent of which could only be inferred by its ability to support the aurora borealis. These auroral phenomena appeared at altitudes of 400–500 kilometers (249–311 miles), 200 kilometers (124 miles), and 60–70 kilometers (37–43 miles). In addition to the aurora, meteor trails also gave evidence of atmospheric air at very great altitudes, principally between 150 and 100 kilometers (93 and 62 miles). From the phenomenon of twilight could be observed the existence of air sufficiently dense to reflect light at about 70 kilometers (43 miles) and the phenomenon of “noctilucent clouds.”
Just as Wegener had made the lecture converge in time, so he now made it converge in space, moving much closer to Earth’s surface, to the significant region known as the “Weather Zone.” He reminded his audience that water condensed out in the atmosphere in only an extremely limited zone, below about 10 kilometers. Measurement of the atmospheric pressure showed that about half the mass of the atmosphere lay in the lowest 5 kilometers (3 miles) (and the next 25% at altitudes between 5 and 10 kilometers). Wegener described this region of the atmosphere as the Schauplatz, the “stage” of meteorology, and thus produced a classical unity of place, time, and action converging on the hero himself. All those years of high school Greek and Latin, of Greek tragedy, of classical philosophy, were not to go to waste, nor were they wasted in being prese
nted to a classically trained audience.
Wegener had now brought the lecture out of the past and down from the sky, to Earth and to his subject—that the aim of aerology was to advance meteorology toward atmospheric physics. To do this, it must not only discover but also integrate empirical results into a theory. With Bezold deceased and Aßmann and Berson still at work, the open role in this drama was clear: who would now play the part once held by Bezold? This was precisely the role he proposed to fill, and the next section of his lecture was a tacit assertion that he was the “new Bezold.”
Wegener asserted that the most striking discovery of recent years was the structural discontinuities in the atmosphere marked by temperature inversions. In this way he linked his own modest work on a 1,500-meter inversion to the discovery of the upper inversion (the tropopause) by Aßmann and Teisserenc de Bort. Wegener emphasized the stability and global character of the latter discontinuity and admitted the more uneven and labile character of the layers below it, but he still insisted that the principal theoretical aim of meteorology was the understanding of these discontinuities and the laws governing them: “If this great boundary layer shows such a stable configuration, may we not also, in the apparent chaos of the surfaces within the Weather Zone, be able to discern a law governing them?”46
This, he continued, was a problem too difficult, until recently, for aerology, and its solution and understanding had required aid from another quarter: the study of clouds. The discontinuity surfaces are identical to the surfaces of the clouds, and the variety of these discontinuities and their behavior are given by cloud classifications. This had been Bezold’s contention, and here it led Wegener directly to his own work once again. In this address, all roads of theoretical and practical advance led unashamedly to the work of Alfred Wegener.
So, from Wegener’s standpoint, the principal task of aerology is to determine, with great exactitude, the mean change of the meteorological elements with altitude, not just in Europe but also from the equator to the poles. We must learn, he said, the mean thickness of the layers and their variation with altitude and all associated phenomena. We may then, he argued, approach the next question, which is how these “typical” layer boundaries persist in special cases, cyclones and anticyclones, and the laws governing the ways in which these layers are breached. “Behind all these investigations wait, however, the deeper question to be answered: what is the cause of such layering? What power places, for example, the alto-cumulus level, despite frequent displacements and even destruction, again and again at 4000 m? The same for all the others!”47
All fundamental problems and solutions of meteorology lie in understanding the laws and causes of discontinuities in the atmosphere. This includes the upper inversion at 11 kilometers (7 miles) and the probability that another Sprung (jump) occurred at 70–80 kilometers (43–50 miles). This understanding of the vertical structure of the atmosphere would provide a unified point of view leading to the understanding of global atmospheric circulation.
Wegener concluded his address with three observations. First, to do justice to what was known already from aerological research would require not an article or two but a book. Second, in the study of cyclonic storms, aerology had, within the few years of its existence, demolished every theory ever proposed to explain them. A clear physical understanding of these phenomena, Wegener argued, was nowhere in sight. Third, while the aims of meteorology can be furthered by far-flung stations and a loose global network of expeditions, the understanding of cyclonic storms could only come from a dense net of aerological observing stations (Europe the likely candidate) through which daily observations, like those at Lindenberg, would replace “random tests.”48
We have no record of how this lecture went over with the audience, but at a distance of a century or more it is a remarkably clear and accurate picture of the state of atmospheric physics at that time. Since most of the history of meteorology has told the story of the theoretical understanding of cyclonic storms, the first decade of the twentieth century seems (as in Wegener’s characterization and prediction of major problems) exactly the sort of “prelude to discovery” of the character of cyclones that it turned out to be in standard (and correct) histories.49
A history of meteorology in the twentieth century constructs the story for us: the nineteenth century theorized the energy of storm systems as thermal convection throughout the full atmosphere. The discovery of the stratosphere by Aßmann and Teisserenc de Bort constrained the weather—as in Wegener’s account—to a limited zone from the surface to 11–15 kilometers (7–9 miles) above it. From knowledge of this limitation, Max Margules, at the Central Meteorological Station in Vienna, was able to write a series of papers in atmospheric physics showing that the energy of storms was not convective but advective, not vertical updrafts and downdrafts but horizontal motion—as air masses moved from areas of high pressure to areas of lower pressure, trapped between Earth’s surface and the “upper inversion” (the tropopause).
The motion of these air masses, sliding over one another and past one another on surfaces of sharp discontinuity, led to the postulation of “frontal weather” by Vilhelm Bjerknes (1862–1951) at Bergen. Bjerknes, who was later Alfred Wegener’s friend and colleague, using the results of a dense network of European and North Atlantic aerological stations (which Wegener had insisted was necessary), was able to produce a series of synoptic maps showing the possibility of weather prediction out several days by analysis of the evolution of storm systems. The latter were to be mapped as waves moving along the “frontal boundaries” between coherent, adjacent air masses. It was this hydrodynamic theory that led forward to modern meteorology as we daily experience it on television, in print media, and on the Internet. Indeed, this work by Bjerknes led directly to an attempt by Lewis Fry Richardson in 1917 to explore the prediction of the weather from “meteorological elements” alone, by calculation of the motion of air masses and by solution of a series of fundamental equations governing the flow of air around the world.50
From the standpoint of weather prediction and dynamical meteorology, Wegener was not on the “main line.” But he was on the main line of advance in atmospheric physics, whose future he predicted with remarkable perspicacity. It is important to keep in mind that Wegener was never, except temporarily and accidentally, a forecast meteorologist, but rather an atmospheric physicist who saw his work as a contribution to a general physics of Earth and indeed the whole cosmos.
With his demonstration lecture completed, Wegener could now move forward with the more mundane details attending his new life. He arranged lodging for himself from 1 April, rooms in a pleasant Georgian brick house at Wilhelm Rosestrasse 9. From this residential neighborhood on the north side of the Oberstadt, it was a vigorous ten-minute walk, up a winding, cobbled alleyway flanked by gardens and cottages, to the Physics Institute at Renthof 6. Walking uphill, one had an agreeable view of the Schloß (palace) and the buildings of the old town. Walking downhill, one had the engaging prospect of the rolling hills and farms just beyond Wegener’s residential neighborhood.
Exploring the environs, he discovered that the prevailing winds were from the northwest, often driving clouds up and over the palace. Beyond the university and over the hill was the market square, with a pleasant breeze filtering through the narrow streets flanked by their fifteenth- and sixteenth-century stucco and timbered houses. The Rathaus (city hall), with its large clock, complete with a bronze rooster flapping its wings as it crowed the hours, had the sort of droll, “not-taking-itself-too-seriously” attitude that was extremely congenial to Wegener. It seemed a calm and quiet place. Away from the train station a mile outside of town, the city was nearly silent; in the Oberstadt, above the city, there was almost no vehicular traffic.
With these matters concluded, Wegener took leave of his new department chair, Richarz, and returned to Berlin. There was much to prepare and to wrap up, including a planned visit to Copenhagen for eight days, to oversee the printing of his Gr
eenland work, to visit with his friend Koch, and to have a face-to-face meeting, long postponed, with Prof. Warming, the head of the Danmark Expedition Committee. There were bundles of proofs to correct, including articles by his brother Kurt, then in Samoa, which Alfred had promised to handle in order to save the turnaround time.
On 22 March 1909, Wegener wrote to Aßmann, sending along corrected proofs and promising that if everything went well, the rest of these would be dispatched before he left for Copenhagen on Friday, 26 March. But things did not go well. On the twenty-third he began to feel tired, and by evening he was feverish. On the twenty-fifth he sent a brief note to Aßmann telling him that he had fallen ill, would not be going to Copenhagen, and for the rest of his time in Berlin would be living with his parents.51 He was, in fact, seriously ill with influenza, not a mild flu but an epidemic version that swept through Europe in the winter and spring of 1909. It was the most severe influenza to appear since 1889, and it struck everywhere: the pope, the king and queen of England, and a variety of lesser notables canceled trips and took to their beds. The fatality rate was high in Berlin and even higher in England, where there were 9,000 recorded dead that year from the flu.
Wegener had been pushing ahead strenuously to tie everything up before his move, and he was vulnerable on several counts. He had been sedentary for many months after years of physical activity, he was smoking heavily, and, not least, he was immunosuppressed, as are all returnees from the antiseptic air of the Arctic. His condition worsened rapidly, and by the twenty-ninth he was completely bedridden and so weak that he could not lift his pen. He dictated to his mother a letter to the committee in Copenhagen postponing his voyage there, pleading for the rapid publication of his Greenland work, required for his employment in Marburg, and asking that his stipend for the remaining Greenland work be continued beyond 1 April. His relocation to Marburg had left him financially embarrassed, a situation that would persist for a long time.52
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