There are additional echoes here with his earlier work. He was constructing, or was about to construct, a “time series” of observations of tornadoes. His dissertation in astronomy had been an extension of the time series of observations of the motion of the Moon back to the thirteenth century. His hypothesis of continental displacements depended on establishing a time series of longitudes for Greenland and North America and of latitudes for India. His contribution to Aßmann’s Festschrift had pointed out that the historical record of the observation of the change in color of large meteors would be a valuable source of data for understanding the chemical differentiation of layers in the upper atmosphere. Modern approaches to these observations were of such recent vintage that pursuing a variety of clever stratagems for gaining information indirectly, from earlier documents, was an important scientific strategy, and one that came repeatedly to Wegener’s mind when faced with a difficult problem.
While planning this work in July and August, Wegener was making hurried preparations for his return to the war; he was now scheduled to report for duty in Berlin on 1 September. He had taken Else, Hilde (or “Hildemops,” as she was now known), and the hired girl to visit his parents and Tony at Zechlinerhütte. He was pleased with the health of his parents and sister, and they were enjoying their visit; things were going well.118 He wondered whether Else’s mother might come and stay with her and the baby in Marburg now that his orders to Berlin had come through.119 When the Wegeners returned to Marburg in early August, Alfred reported to his father-in-law that he and Else worked every afternoon in their garden, and that Else was constantly cooking and putting up vegetables as a wartime food reserve.120 Rationing was already in place, and some foodstuffs were beginning to be in short supply.
Along with her strenuous domestic routine, Else was also pursuing her scientific work: she was translating an article by Koch, on his Greenland glaciological work, for the Zeitschrift für Gletscherkunde. The work had been passed her way by the journal’s editor, the great Austrian geographer and climatologist Eduard Brückner (1862–1927), who just happened to be her godfather.121 The young couple was, in every way, squeezing as much normal life as they might into the few remaining weeks and days—both work and play. But time was very short, and they knew it.
14
The Meteorologist
“IN THE FIELD,” 1916–1918
Such people will refuse any reorientation of their ideas. If they had already learned the displacement theory when they were in school, they would defend it for their whole lives with the same lack of understanding, and with the same sort of incorrect information, they now use to defend the sinking of the continents. The best thing is just to wait until they die off.
WEGENER TO WLADIMIR KÖPPEN, 25 December 1917
Wegener was called back to service in Berlin in mid-September 1915. October found him at the registration office (Melde-Amt) at German headquarters in occupied Antwerp, Belgium, where he briefly served as an adjutant.1 By early November, he was in Tongeren, in eastern Belgium, and well behind the front lines, where the Germans were building a major railhead to supply the front, and which also seems to have had a military airfield.2 It is not clear how long Wegener remained there, but by January 1916, 1st Lt. Wegener was in the Field Weather Service of the German army, as commanding officer of Field Weather Station 12, in Mülhausen, in the far south of Alsace. Nestled in the triangle between the French, German, and Swiss borders, it was both an administrative center and the southern anchor of the German lines on the western front.3
Mülhausen
Wegener’s duties as a field weather officer in Alsace throughout 1916 were much like his duties at Lindenberg in 1905–1906. Field Weather Station 12 was one of many such stations in a synoptic network extending throughout Germany, occupied Belgium, and France—and into Poland as the Germans continued to drive the Russian armies back in the East. The cadre of officers under his command made observations at fixed times each day, including kite and captive balloon ascents, and they also sent up pilot balloons to measure the winds at higher altitudes.4 The latter were especially important as they determined the operational range of aircraft flying into the face of prevailing westerly winds. Bombing and reconnaissance aircraft could, in 1916, fly at altitudes of 2–3 kilometers (1.2–1.9 miles), somewhat above the usual range of kites and captive balloons. The staff officers (and Wegener) telegraphed daily weather observations to central weather stations, to be combined into synoptic weather maps of the kind developed by Bjerknes at Leipzig, in order to forecast prevailing winds, temperatures, precipitation, and especially cloud cover, the last because all airborne navigation was by landmark.
The relative safety of Wegener’s assignment and his consequent lack of strain, the regularity of his duties, and the presence of assistants and subordinates, including an orderly, left him with time and inclination to pursue his own meteorological research. He devoted these (many) free hours throughout the first seven months of 1916 almost exclusively to his book on Tromben (whirlwinds). His time in Mülhausen was vastly more comfortable and more congenial to scientific research than either of the expeditions to Greenland. He missed his home and family, but his sense of being divided between duty and science had vanished: now his military duty was science. He was quartered with his officers in a villa abandoned by its owner, and the only source of strife seems to have been keeping the peace between the cook, who had stayed on, and his junior officers.5
Wegener’s most regular (surviving) correspondence with Wladimir Köppen is from this period of time, and these letters show a sense of intellectual excitement, energy, and an appetite for work. Most have to do with the difficulties, failures, and successes of his book-length catalog of all European tornadoes since the 1500s. Wegener had access to the library at University of Freiburg, some 48 kilometers (30 miles) to the northeast of Mülhausen and only a short trip by rail.6 This university access was vital in obtaining periodical series and monographs in which he could find accounts of tornadoes. His proximity to Freiburg also allowed him regularly to visit with and converse with Kurt, who was in 1916 commander of a bomber squadron based there, and who was writing, between bombing and reconnaissance sorties, a book on the future scientific use of fixed-wing aircraft.7
Köppen was his usual helpful self, obtaining records of tornadoes from his collection of reprints, from the library at the German Marine Observatory in Hamburg, and from Julius Hann in Vienna, and Gustav Hellmann in Berlin also rendered assistance and provided materials that were difficult to find.8 Frequent rail service, as well as the importance of Mülhausen as administrative center for the German military on the western front, sped the post and ensured the safe arrival of parcels of books and papers.
By early February things had settled into a routine and Wegener felt that his work was going well, though the material on whirlwinds was “hard to knead into shape.”9 This is not surprising: he was drawing on descriptions of tornadoes from a variety of sources, written with different levels of scientific understanding, with widely varying detail, and in different languages, across a span of 400 years. Moreover, he was (for once) not guided by a theoretical idea and was not interpreting a data set. Rather, he was committed to assembling one. He not only lacked a guiding theory but also refused, as a principle of organization, to entertain one; selecting data to fit a guiding theory of tornadoes was precisely the flaw he found in all previous compendia on the subject.
Tornadoes and Waterspouts
In spite of these difficulties, by early March he could write to Köppen that he was fully committed to going forward with the book. He felt compelled to emphasize once again that “it is not so much an investigation, but rather more a compilation, and this will make it much easier to read.”10 By this he certainly meant that there would be little or no complicated mathematical apparatus, and no hydrodynamic theorizing requiring a specialized knowledge of this area of research. The pace and character of the project suited his circumstances, as it was the kind of wor
k which could be picked up and put down without the necessity of reestablishing a complicated train of thought.
His principal concern was straightforward: how to organize the material and how to manage the details of publication.11 Part of the problem of organization was solved by the quality of the various descriptions. He had a relatively small number of detailed descriptions by naturalists and scientists who had observed and carefully recorded individual instances of tornadoes and waterspouts, descriptions that had been published as whole scientific articles. He would present these, perhaps a dozen or so, in an introductory chapter. Then he could proceed with a chronological catalog of all known descriptions in the scientific literature; this looked to be 200 or 300 items. These could be listed by date, place of occurrence, author, publication, and whether or not the text was accompanied by an illustration.12 This list of descriptions he could then “data mine” for statistical analysis and for grouping under various topical headings: size, direction, length of path, weather at the time of occurrence, and as many other categories as he could think of.
In early April he was expanding his search for tornado records, by contacting observatories to obtain weather maps for the days on which tornadoes occurred, and even obtaining simple lists of “weather events” from the Marine Observatory in Hamburg, hoping to uncover in them records of tornadoes not otherwise reported. Despite his promise not to theorize, he could not help seeing patterns. His early statistical analysis showed that in the United States most tornadoes occurred in the spring, with very few in the winter, while the reverse was true in Europe. How to explain this? Could it be because in America the ocean was to the east, while in Europe it was to the west? Such ideas would find their way into the final book in isolated sentences, not organizing principles.13
Continental Displacements, 1916
April 1916 also brought to him the first reviews of his book on continental displacements, and the news was surprisingly good. He had sent a copy of the book to M. P. Rudzki (on whom he depended so much for geophysical data), hoping that Rudzki might review it, and indeed he did, in Die Naturwissenschaften. In the review, Rudzki praised both the “clarity and elegance of the style, that makes the reading of Wegener’s book very pleasant,” and Wegener’s command of the literature supporting his hypothesis, which was “completely free of inaccurate representations [of the work of others] or misunderstandings [of their arguments].” Rudzki cautioned that Wegener had probably overstated the accuracy of gravity measurements over the ocean and the certainty of large-scale gravity differences between the ocean floor and the continental surface. He also noted that longitude measurements could shift as a result of the warping of the continental surface caused by local deformation and mass displacements, and that quite large latitude and longitude differences would have to be measured and confirmed before actual alteration of the distance between two continents could be assumed. He concluded, “Wegener shows that his hypothesis explains very well a variety of observations concerning continental morphology, geology, zoogeography, phytogeography, and so on.”14
Wegener’s ideas were also finding their way into standard textbooks even before the initial cycle of reviews had run its course. For example, Alexander Tornquist (1868–1944), professor of mineralogy and geology at the University of Graz in Austria, gave Wegener an enthusiastic notice in the introduction and concluding sections of the second edition of his Grundzüge der allgemeinen Geologie (1916). He described Wegener’s “bold” hypothesis as something “far from our current conceptions,” but nevertheless an idea of great interest and promise, worthy of further development and demonstration.15 Such enthusiastic endorsements appeared, naturally, in parallel with doubts and criticisms expressed by other (and equally established) writers. Franz Kossmat (1871–1938), director of the Geological and Paleontological Institute at the University of Leipzig, in the second (1916) edition of his Paläogeographie, wrote (like Tornquist) of the “bold hypothesis of Wegener” but found Wegener’s notion of the dispersal of the southern continents “beset with tectonic difficulties.”16
The reception of Wegener’s ideas in this area of science was actually somewhat warmer than the reception of his textbook of thermodynamics in his own specialty. No reviewer mentioned or referenced, in any of the reviews and notices in 1916, Wegener’s scientific specialty (i.e., that he was not a geologist), and all referred to him simply as Wegener, A. Wegener, or Dr. Wegener. Established geologists, geophysicists, and paleontologists do not seem to have viewed him as an interloper or a beginner. His own self-identification on the title page of the book had been “Instructor in Meteorology, Practical Astronomy, and Cosmic Physics in the University of Marburg.” He also mentioned the measurement protocol between North America and Germany (and its abandonment because of the war), and he declared that he had only undertaken the scientific task of expanding the argument to pass the time during his rehabilitation leave, subsequent to being wounded in battle.17 He was glad of the reception of the work and felt that he was now part of a dialogue with a range of coworkers, sponsors, and colleagues working full-time in geology and geophysics.
As exciting as this was, he had pressing concerns that diverted his interest away from continental displacements. He wrote at this time to Köppen that he would finally be eligible for home leave at Easter (at the end of April); he had not been home for seven months.18 There had been a few hurried meetings with Else, in train stations when he knew his route (often to Berlin), or returning to the field, when he had managed to send her a telegram in time. Else wrote, in her memoir of this period, that this was the way they saw each other throughout most of the war between 1915 and 1918. Sometimes they found each other; sometimes they missed connection. Else learned to consult the registration books in the train stations, as all officers were required to sign in at the moment of their arrival, so she would know whether Alfred had not yet arrived, was still there, or had come and gone.19 Now, at Easter, they would actually spend a span of days together for the first time in more than half a year. Arriving in Marburg in mid-April for his two-week furlough, Alfred was overjoyed to be home, to see his wife and child, and to be among familiar surroundings.
The Treysa Meteor
Upon his arrival in Marburg, he learned of an astonishing astronomical event earlier that month. On 3 April, at about 3:30 p.m., a huge fireball/meteor had streaked across the sky and detonated and crashed somewhere in Hesse. Richarz was wildly excited, as was Kayser, and they were desperate to locate it, as it had clearly landed in “their backyard” very near Marburg. Knowing that Alfred had written about color changes in large meteors, they sought his advice on the matter, and Wegener not only agreed to help them but told them that he would find the meteorite for them.
He was glad to help his patrons in their search, as he felt himself deeply in their debt. In his absence, Richarz (and Aßmann, from Berlin) had bombarded the Ministry of Education with appeals to establish the special examination in cosmic physics which Wegener had requested, the better to position him for a professorship in this topic at Marburg. They had also, with the concurrence of the dean of the university, urged that Wegener—not only a promising young scientist but also a wounded war hero—be made a titular professor for the duration of the war. At the forefront of this calculation was the unspoken desire to provide his wife and child with a steady income. Unable to offer courses and unable to work in the astronomical observatory, Alfred’s stipend would always be in danger, and a professorial title could stabilize his finances and situation.20
This debt to his patrons notwithstanding, the search for the meteor was clearly a labor of love, and even a sort of fascinating game. The work that came out of it was a minor part of his scientific legacy, yet it is one of the most polished and thorough pieces of work he ever did.21 Wegener was well prepared to write about the topic; he had just considered the color changes in large meteors, in his contribution to Aßmann’s retirement volume. He had been at work for many months assembling newspaper and periodica
l accounts of the occurrence of tornadoes and had developed a strong interest in determining the accuracy and usefulness of (lay) accounts of unusual meteorological phenomena; this was certainly one such event. Finally, he was a trained astronomer, with a degree from a department that specialized in the tracking of near-Earth objects: asteroids, comets, and meteors.
Wegener began his search by writing to major newspapers in Frankfurt, Cologne, and Magdeburg, to assemble press reports of the meteor. The descriptions in these news reports allowed him to determine that it had indeed fallen somewhere in Hesse, and that the limits of visibility approximated the Rhine River to the west and the Main River to the south. Armed with this information, he wrote to fourteen additional local newspapers. From their reports he was able to divide the recorded observations into those that had seen the fireball and those that had both seen the fireball and heard the explosion. He could also plot on a map (with small arrows) the direction of travel of the meteor as seen from the standpoint of each recorded observation. From these descriptions he was able to inscribe a circle on the map, with a radius of roughly 125 kilometers (78 miles), within which all the sightings appeared. He located its center by the directionality of the arrows of the observed meteor path, placing it in the area of the greatest density of those observers who had seen the fireball and also heard the detonation.22 This put the likely impact site near the village of Treysa.
He requested and obtained an extension of his leave in order to complete the investigation, and between the ninth and twelfth of May he traveled to the vicinity of Treysa (two days with one of his colleagues, and two days with Else), where he went house to house and farm to farm collecting testimonies of what people had seen and heard. This pleasant and diverting foot tour brought the number of observational accounts to more than 100.23 Wegener asked his informants to sketch the shape of the fireball, and for those who had seen the meteor in the last few seconds before it hit the ground to indicate not just the direction of travel but the angle and the appearance of the smoke plume. The persistence of a smoke plume (for more than a minute) allowed a better sense of the direction and angle of incidence. He asked them about the sound and about the color, and he got wonderful descriptions. It was described variously as white, gleaming silver, yellow like the Sun, lemon yellow, blue like an acetylene torch, blue like the fire of hot coal, black with red streamers, and a red core surrounded by a green halo. This was, of course, what he expected—that the color should change based on the altitude of the meteor at the time of observation.24
Alfred Wegener Page 65
