It is because of Milankovich that we know about Wegener at Innsbruck. The two had never met. Milankovich had come home from a business trip in the late spring of 1924 and found the page proofs of Köppen and Wegener’s book on his desk, with a note from Köppen asking for him to review them. He had done so and thought little more about it until he got the letter from Rella; he decided immediately to go to Innsbruck.
When Milankovich and Rella arrived in Innsbruck in September 1924, they went looking to meet friends and then spent the evening moving from restaurant to restaurant, trying especially to find Wegener. They found him in a beer garden, drinking with Heinrich Ficker and brother Kurt. Milankovich remembers that even though Wegener was then forty-four, he was “slim and fit with a gentle expression in his gray eyes and a slightly melancholic smile around his thin lips; he looked considerably younger.”17 Rella and Milankovich sat down, and by his account the five of them sat talking until late into the night, arranging to meet for dinner the next night at a wine cellar just out of town.
Wegener’s lecture took place the next day in the main lecture hall of the newly refurbished university (which had been occupied by the Italians during the First World War and rather badly damaged). Much to Milankovich’s surprise and delight, when the lights went down and Wegener began to lecture, it was not just about the theory of continental displacements but also about the application of that theory to the climates of the past.
Wegener spoke using projection slides of his maps for each period of the past beginning with the Carboniferous, and he methodically explained his use of coal, salt, and ice to map the migration of the latitude zones. He continued through each of the eras of Earth history until he arrived at the Quaternary, at which point he began to talk about the importance of Milankovich’s work, “which we included in a short chapter in our book.” Wegener gave a detailed discussion of Milankovich’s work and its correspondence with the geological sequencing of the ice ages worked out by Penck and Brückner, as well as the fineness of the correspondence between Milankovich’s mathematics and the geological details. Milankovich was thrilled. It was the first time he had ever heard his work discussed in public. He said that Wegener’s lecture made a great impact on the assembled audience and “prompted a lively discussion, in which I did not participate, about his theory.”18
In the discussion following the lecture, Schweydar, who had spoken so favorably of Wegener’s work in Berlin in 1921, now raised strong objections to the extensive displacement of the poles required by Wegener’s theory, in light of work done in the previous few years in geophysics suggesting that these extensive motions were unlikely and perhaps impossible. Wegener had responded that he must defer to Schweydar and the other geophysicists, as “my mathematical knowledge is insufficient to disarm known experts.” However, he added, “the geological evidence supports the claims I have made here.”19
A few days later, Milankovich wrote to Wegener, saying that the lecture had stimulated his interest in a whole range of questions and asking him how he might obtain a copy of Wegener’s work on the origin of continents and oceans. He also solicited a copy of Wegener’s lecture so that he might publish it both in French and in Serbian. Strange as it may seem, given Milankovich’s collaboration on the book on climates of the past, he had never read Wegener’s theory, learning the details only during the Innsbruck lecture. Milankovich also asked Wegener whether it was possible that there had been a secular decrease in the solar constant (i.e., the amount of radiation emitted by the Sun) as part of the change in Earth’s past climates.20
Wegener responded warmly on 6 October, begging a few days’ grace in sending him a copy of the lecture, as his family was to arrive in two days. Wegener went on to say, “I would especially welcome it, if at some time you tackled the question of polar movement, even if a straightforward solution should not be reached. It would be very important if it were established at some time what, up till now, theoretical science has to say about this problem.”21
On the question of the solar constant, Wegener thought that the presence of an ice age in the Archaean (Algonkian), along with the fact that “in the Mesozoic era, the climate of the then south polar region was milder than the present polar climate; all traces of inland ice are missing from this long period,” argued against a long-term decrease in solar radiation. Moreover, Wegener said, “It often strikes me that both main periods, with great amounts of glaciation at the poles (Permocarboniferous and Pliocene-Quaternary) coincided with periods of intense mountain formation and rapid polar movement. I have a feeling that these things may have a common cause.”22
Wegener needed geophysical and astronomical help. It was a curious reversal, when we consider that in 1912 and 1915, and even in 1920, the principal thrust of his theory of the origin of continents and oceans was to sort out candidate geological theories of the continents based on the adequacy of their geophysical foundation. Now, as the author of a thoroughly geological treatise on the climates of the geological past, he found his geophysical assumptions under stress. In 1921, Schweydar, Epstein, and Lambert had separately challenged the adequacy of the “pole-fleeing” force to raise mountains. Now, in mid-1924, Schweydar was questioning whether the poles could move at all in the way that Wegener needed them to move. Wegener had already been forced to reduce drastically the amount of pole shift in the Quaternary to accord with Milankovich’s astronomical parameters. It was a serious quandary, as Milankovich’s pole shifts were astronomical and absolute, and Wegener was now no longer sure what he meant by “pole-shift.”
He now had several options to consider. How much had the poles actually shifted, and how much of the shift of latitude zones was a matter of continental displacement alone? The decision to measure displacements against an Africa fixed in place was a necessary heuristic device, but it seriously confused the issue of the absolute amount of continental motion, relative to a given pole position, and the absolute amount of displacement of the pole of rotation relative to the fixed stars. He still remained committed to the “verdict of the exact sciences” but was no longer certain what that verdict was.
Else arrived two days later with the children. She set about finding a house the very next day, 9 October 1924. Within a few days she had located a “nice house” in what she described as “the suburbs”—which did not mean much in a place as small as Graz, as it was a leisurely twenty-minute walk to the University Physical Institute and close to a primary school. Her efficiency in these matters (in comparison to Wegener’s lack thereof) is sometimes startling. The house she chose was on a gently sloping and curving street, the Blumengaße; the house was No. 9. It was in a series of what we would now call “townhouses,” sharing a continuous facade along the block, and built in 1910; No. 9 was on a corner lot and had windows on three sides. It had a high-pitched roof, a back garden, and a “daylight basement,” so it was actually four stories tall.23
Finding enough money to buy it was a problem, as the Hamburg house had not yet sold, but Benndorf stepped in and informed Wegener that under such circumstances the Ministry for Instruction could provide an advance on his salary sufficient to purchase the house. Wegener traveled immediately to Vienna, and after two days of negotiations, he returned with enough money to buy the house. They moved in immediately, even before the furniture arrived, but by early November the house was, as Else said, “halfway livable” and ready to receive her parents.24
When Wladimir and Marie Köppen arrived in mid-November, the family, again united, seems to have made the transition to life in Graz rapidly and easily. Köppen had left all of his official and scientific correspondence, dating back well into the nineteenth century, to the Prussian State Library in Berlin, and they were happy to have it. He brought his extensive library to Graz, but he saw immediately that space in their new house would be at a premium; he therefore donated most of it, about 3,000 volumes in thirty-four large crates, to the Meteorological Library in the Physical Institute, which he had learned was rather limited i
n resources. In return, the university named him an honorary member of the faculty. After all the years he had lived in a distant suburb of Hamburg, he was delighted to be only twenty minutes or so away from the university and made the walk almost every day of the week. He also enjoyed the vegetation, which he said reminded him of the Crimea of his youth.25
The family quickly settled into a comfortable routine. Other than a shortage of money the first year because of the salary advance to buy the house, Else said, “Without any extraneous worries we could now set up our lives the way we liked. Alfred and I each had our own spheres of activity that left us completely fulfilled, and we were soon quite at home.”26
One must remember that from Else’s standpoint their lives had been one continuous emergency since his return from Greenland in 1913: Alfred’s mother’s stroke, the birth of their first child, Alfred twice wounded and once nearly dead of dysentery, with him being away from home for almost four full years. Then there was the death of Alfred’s father, the death of one of her brothers, the arrival of two additional children, the death of Alfred’s mother, and the very difficult years 1919–1924 in Hamburg, where, toward the end, they were nearly penniless and growing their own food in vacant lots while running a huge household always short of fuel, and with none of the domestic servants one might normally have associated with people of their social standing and professional rank.
For Else, Graz meant stability, adequate means, frequent and pleasurable vacations, a good home for the children, and a chance to see more of her husband, although he was never home as much as she wished. She remarked sardonically, concerning the roster of weekend hikes, handball games, cross-country ski tours, and Alpine vacations, “All of these undertakings were only the background music for my husband’s real passion: the advancement of his scientific work.”27
Wegener was available for some but not all of these undertakings. Else said that she often had to use all her powers of persuasion to pry him away from his writing desk, even on a Sunday morning. Typically on Sundays in good weather the Wegeners would get together with other families, for a stroll along a stream or to a park, often with a game of handball during the noontime picnic break. Team handball was a sport that Germany and Austria were mad about in the twenties and thirties, and its rules were just being codified. It was also playing a significant international role, as the reentry of Germany into international society and cooperation began with sporting contests, notably a team handball match between Germany and Belgium in 1925, an unspoken beginning to a difficult but necessary reconciliation. Wegener laughed at these games and hikes, calling them “Tieftouren,” an untranslatable play on words which could mean either “hiking a stream” or “whirlwind tour,” meaning that they were not proper mountain hikes and that they were too short to be interesting. Generally, he went along, if only “because he needed the fresh air and the exercise.”28
Wegener’s work rhythm in Graz was to pursue a project relentlessly, day and night until it was complete, or until he could make no further progress. When he finished, and for him finishing meant a manuscript of some sort to be sent to a journal, it was time to get away. Else said she could always count on getting a few days with him in the mountains every time he finished a big project. He felt, and she knew, that these trips were absolutely essential to clear his mind to get ready for new work. Moreover, in the Graz years, the family took regular summer vacations in the mountains, sometimes lasting several weeks, and she said that for him these vacations were real vacations, and that he never took scientific work along with him.
In the fall of 1924 Benndorf, who had been very impressed by Wegener’s presentation in Innsbruck, asked him if he would consent to repeat it at greater length, in Graz, having time to dwell on both his theory of displacements and his work on climates of the past. Wegener agreed, delivering these lectures on 21 and 28 November 1924, followed by a full evening of discussion on 29 November. These were sponsored by the “Physics Section” of the Steiermark Scientific Association, and invitations were also sent to the members of the geology, zoology, botany, and geography sections, so it was in essence a “plenary session,” for the entire scientific community.
Benndorf, already astonished by Wegener’s intuition in problem solving at the Institutstee, was also impressed by Wegener’s mode of presentation during these lectures. “He began without any introduction,” Benndorf remembered, “with plain and simple words, almost sober and dry, and in the beginning, somewhat halting.”29 When he began, however, with systematic clarity to lay out the arguments first from geophysics and then from geology, paleontology, biology, and paleoclimatology, “he became more and more animated, his eyes flashing, and his hearers were carried away by the beauty, grandeur, and boldness of the intellectual structure he had created. Never have I been more aware of how inessential rhetoric is for the effect of a talk when its object has such a clear significance.”30
Benndorf was even more impressed during the evening of discussion on the twenty-ninth. A number of objections were raised to Wegener’s theory, and many of them, said Benndorf, “to my way of thinking focused on inessential points.” Wegener answered every one of them without a trace of irritation, clearly, with careful deliberation. One felt, Benndorf said, the full weight of his mastery of the enormous range of scientific material he had brought together in the service of his theory.31
Though Wegener continued to follow developments with his hypothesis and to accept invitations to speak about his work on continents and oceans, especially on the climates of the past, the move to Graz coincided with a major shift in his scientific work. He had been completely consumed between 1919 and 1924 in developing and working out all the consequences of his theory of displacements. With the publication of Klimate der geologischen Vorzeit, he felt he could turn to other interests, long neglected.
He told Else when they moved to Graz that he would now have a chance to lay the foundations for the complete physics of the atmosphere he had wanted to produce as early as 1911. There was really nothing more for him to do with continental displacements in 1924; the book was being widely read and translated. Klimate der geologischen Vorzeit had not yet had time to make an impression. Irmscher had written to Wegener from Hamburg in early November 1924 to tell him that Gothan (the paleobotanist who had updated Potonié) had just published a book in which he had taken a position against Wegener, but without having seen the Köppen and Wegener climate book.32 On the other side of the ledger, a Danish expedition to West Greenland in 1922 to update the geodetic measurements had determined a westward drift of Greenland corresponding to an annual westward displacement of more than 20 meters (66 feet) per year since 1873, for a total of 980 meters (3,215 feet), which corresponded very closely to Koch’s East Greenland measurements.33 Moreover, the International Geodetic and Geophysical Union Congress that had just met in Madrid in October 1924 had announced a plan to coordinate radio time signals in a network of circumglobal stations in order to unify geodetic and astronomical observations. This plan was publicized by some participants at the congress, but not by the congress itself, as a means to try to measure continental displacements using radio time signals.34
Owing to the combination of his teaching of meteorology at the University of Hamburg and his growing celebrity, the initial printing of his Thermodynamik der Atmosphäre (1911) had finally sold out, and his publisher wanted to issue a new printing. He consented, though it reminded him that that book was to have been only the first part of a general physics of the atmosphere which would also include mechanics, optics, acoustics, radiation, and atmospheric electricity. To this project he could now turn his attention.
It may come as something of a surprise that the author of a major theory of Earth’s origin, physical constitution, and evolution, as well as an allied theory of global climate change throughout the whole span of Earth history, should suddenly cease to work on that problem and go off to do something quite different. Actually, for some scientists, this is not so unusual.
Students were always arriving in Göttingen to study some problem with the mathematician David Hilbert (1862–1943), only to discover that he was no longer working in that area of mathematics and had moved along to something else. Wegener would continue to monitor the fate of his working hypothesis—his theory—but for the present he was no longer actively involved with its development.
He elected to teach, in the fall and winter of 1924/1925, an extensive elaboration of his Optik der Atmosphäre. Perhaps an encouragement to this work was that Felix Exner had brought out a second edition of his 900-page treatise on meteorological optics in 1922. This book was known as “Pernter–Exner” because Exner had completed (in 1912) the manuscript left behind by Josef M. Pernter (1848–1908). It was a classic in the field and still in print, but Wegener thought that it needed work, especially in the area of mirages, his own specialty, and in the phenomenon of “halos,” to which he had given a great deal of attention and on which he had published briefly during the war. In any case, Pernter–Exner was a gigantic reference work, and what was needed was a compact treatment that could go into a single-volume textbook on atmospheric physics.
Alfred Wegener Page 94
