Classroom and Laboratory

Kolbe's teaching was from the first very successful. His letters suggest that he put a great deal of energy and thought into his lectures and practica, and the students seem to have responded very favorably. From as early as November 1851, Kolbe often spoke with pride and confidence of his students. Given one assistantship by the university, Kolbe filled the position during his first few years in Marburg with undistinguished chemists; later followed the much more capable Rudolf Schmitt (1857-1861) and Eduard Lautemann (1861-1865). Schmitt subsequently made a career at the Dresden Polytechnikum. Praktikanten and guest workers from the Marburg period included Adolph Claus, Edmund Drechsel, Georg Fischer, Wilhelm Gerland, Carl Graebe, Peter Griess, Ludwig Mond, Carl Ulrich, Jacob Volhard, and Julius Ziegler; foreign students included Frederick Guthrie, Alexander Crum Brown, E. T. Chapman, N. A. Menshutkin, Maxwell Simpson, Francis Wrightson, and A. M. Zaitsev. The paucity of students in the early and mid-1850s was a source of frustration for Kolbe, who had more ideas for research projects than he had skilled hands available to him.^[71]

Guthrie gave his friend Henry Roscoe an intriguing picture of what it was like working with Kolbe in 1854 (he noted that he was the only organiker in the lab at the time and was working on electrolysis experiments):

I am obliged somewhat to take the law into my own hands, and stick to one thing 'till I've got a distinct result or nonresult, for my much honoured professor comes almost every morning with "Herr G. es ist mir eingefallen dass Sie so u. so ein Versuch machen können," etc and the most provoking thing is that the "Versuch" is often so tempting that it requires no small amount of moral courage to keep in the straight and narrow path.^[72]

In 1855 Kolbe described Guthrie as a "well-educated man . . . very industrious . . . and extremely nice," with some fine chemical research already to his credit. Guthrie went on to become Frankland's assistant at Owens College, eventually gaining a professorship at what became Imperial College in London. He became a physicist and had a distinguished teaching career.^[73]

In summer semester 1862, Carl Graebe also studied with Kolbe and described his impressions and his schedule in letters to his parents:

I like Professor Kolbe very much indeed. Only the laboratory equipment is unfortunately deficient. . . . I rise at six, read a little, and about seven-thirty walk to the laboratory, where I remain until dinnertime, with the exception of two days, when I ride from 11 to 12. In the afternoon I am in the laboratory from 2 till 5 or more often 6. Then I bathe and take a walk; by around 9 I am usually home, so that I use my lamp more than I expected. Kolbe pleases me ever better; he gives a magnificent lecture.^[74]

Jacob Volhard, a Giessen Ph.D. who worked with Kolbe that same summer, described the lab as an ordinary-sized, low-ceilinged room (it was about 25 by 35 feet), crammed with twelve to fifteen workers, each with his own charcoal fire as well as alcohol lamp. It was intolerably hot, crowded, and confined, usually filled with noxious vapors and possessing no ventilation, running water, or gas. And yet, Volhard added, he and all his former lab mates looked back on their Marburg years with nothing but fondness.^[75]

Henry Armstrong, who studied with Kolbe in Leipzig in 1867-1870,^[76] regarded him as "a true chemist if there ever was one" and never thought of him "in terms other than those of admiration and affection," although Armstrong did concede that he later became "peculiar" and "little short of a monomaniac." He was "almost bourgeois in appearance, a typical professor of the old school, though with a wonderful sparkle of intelligence in his eyes and a most endearing personality when you learnt to know him—not the ogre he has been painted." Armstrong also characterized him as "a puritan and an enemy of insincerity," honest and forthright in the greatest degree, and subsequently much misunderstood and unjustly neglected.^[77] Ernst yon Meyer emphasized that it was necessary to be in Kolbe's inner circle of friends in order to see his warmth, amiability, and humor.

In personal intercourse with him the sharpness typical of his critical writings was entirely absent. A social man, inclined toward merry jokes, fond of witty rejoinders and word plays, he was entirely different from the impressions of those who viewed him from afar.

The violence of his opinions, Meyer concluded, was due entirely to the fact that he was "a fanatic for the truth" and always insisted on speaking his mind no matter whose toes he was stepping on.^[78] Ost, also a student, relative, and obituarist, chose almost the same words: "The image of Kolbe impressed on his immediate surroundings was substantially different from the appearance from afar. Kolbe was a

complete gentleman, and moreover of exceptional amiability and benevolence."^[79]

Kolbe was an enthusiastic follower of Liebig's style of instruction, but he faulted Liebig for not going far enough and not remaining completely consistent with his guiding ideas. He agreed with Liebig that chemistry must be taught the same to all students; that it must be theoretically based but also firmly grounded in experimental practice; that the overall goal must be to teach the student to "think chemically"; that the laboratory must be as much a pedagogical as a research institution; and that advanced students must be considered vital scholarly collaborators. Consistent with their Lernfreiheit , students often took a variety of courses in their first two or three semesters before specializing exclusively in chemistry.^[80]

Kolbe thought it best to have beginners complete the lecture course in experimental chemistry before entering the lab, although he never insisted on this in practice.^[81] "The heart of chemical instruction," he wrote, "is not, as in many other disciplines, in the lectures, but rather in practical work in the laboratory." Learning chemistry solely from lectures and books is like teaching a blind man about colors or studying swimming on dry land, he thought. From books, one can learn one's chemical ABCs, even to spell and to write, but to speak, think, or philosophize chemically requires immersion in phenomena . Such emphasis, common to many others in addition to Liebig and Kolbe in the nineteenth century,^[82] is derived in part from a phenomenalist and sense-intuitionist perspective, as discussed in chapter 1. It is also derived from the accurate perception that scientific work is partly craft-based, tightly packed with all manner of tacit knowledge that can only be learned from exemplars and practice.^[83]

We know more about the details of Kolbe's practica than about his lectures, for which we possess no documentation. The first semester in lab was devoted to qualitative analysis. Starting with nonmetals, inorganic acids and their salts, the students progressed through some 110 analyses of compounds and mixtures, concluding with complex and rare metallic compounds. The laboratory course met four days a week, two hours a day, and was overseen jointly by Kolbe and his assistant. Unlike in Giessen, however, no lab manual was used. Instead, close personal supervision demonstrated to each Praktikant the methods of careful observing, recording, and understanding of every reaction, by which he was gradually led essentially to write his own manual. Kolbe and his assistant would carefully examine and critique each student's annotations, allowing nothing to remain unclear. The goal was total immersion in 'phenomena, so that the student truly absorbed into mind and soul the essence of every observation, event, and operation. Like

Bunsen (and not like Liebig), Kolbe spent much time with rank beginners, letting his assistants spend more of their time with more advanced students.

Kolbe thought this combination of intensive personal supervision and self-instruction was twice as efficient as the Giessen pattern, so that by the middle of the second semester of lab work, he regarded most students as ready for the next stage. After about one semester of quantitative gravimetric analysis, the student was put to work for a few weeks making organic preparations, which served the triple purpose of introducing the student to more complicated operations and apparatus, acquainting him at least with parts of organic chemistry, and providing the more advanced students, assistant, and director with starting materials for their research. Finally, the student was taught organic elemental analysis.

At this point, typically after three semesters, the student was assigned the task of studying a classic chemical paper chosen by the professor and was directed to repeat the work or to make a small variation in it. Kolbe thought that this was the best way to induct students into proper scientific method and writing as practiced by the masters of the field. Kolbe would then suggest a small original project, often motivated by his current theoretical interests, that the student could work through essentially independently. From this point on, the student was invited to make his own way through the scientific thickets. Depending on a variety of circumstances, Kolbe might or might not continue closely to direct the work of the student. But in any case, having passed through a two-year chemical novitiate, the student was regarded and treated as an independent worker and was invited to spend about forty-five hours per week in the lab rather than eight. Any publications from the student's work appeared under the student's own name, or as a collaboration if warranted. Early in Kolbe's Marburg period, about a third of the Praktikanten—a small handful at best—were advanced students. By the end of his stay, when he had become famous, more like two-thirds to three-fourths of the workers (ten to twenty) were full-timers. A number arrived in Marburg already with advanced training, even Ph.D.s.

Kolbe thought that it was vital that every chemistry student go through this same apprenticeship, whether they were planning to be "Chemiker vom Fach" or were studying an ancillary discipline such as agriculture, pharmacy, metallurgy, or chemical engineering. Those who followed his course had learned to think chemically, and those who could think like chemists, he believed, would have the mental flexibility to solve efficiently a wide variety of unpredictable problems encountered in their future professions, while those who had followed

the prevailing "cookbook" pedagogy would not have the proper independent and scientific training to succeed. Such sentiments had already been expressed by Liebig in his critiques of Prussian and Austrian chemistry, and Liebig's influence is evident in much of the description just concluded. In one important respect Kolbe had gone beyond Liebig, namely, in his emphasis on personal instruction and on having the Praktikant gradually write his own laboratory manual on the basis of his own personal observations. It is probable that the idea for this pedagogical innovation came from Bunsen, who always preferred that students make their own observations rather than look them up in a book.

Kolbe was proud of the excellent esprit de corps and exceptional diligence of his students. This seems not to have been an idle boast, if his Marburg lab was anything like that in Leipzig. Concerning the late 1860s, Henry Armstrong reminisced

Kolbe's laboratory, in those days, afforded wonderful opportunities. About a dozen of us were doing advanced work, in preparation for the Degree—seeking independence. Each had his Arbeit —his definite problem—in view, as his chief aim in life: we were all proud of being called on to show that we could do something. This was the distinctive feature of the German system. At most two or three had themes from the Professor—the rest were carrying out ideas of their own; the work was, therefore, varied. Whatever suggestion we made to Kolbe, he never discouraged us; his habit was to grasp the lapels of his coat, then to reply: "Try it, try it." We disputed with him constantly before the blackboard, often for hours together, nearly always taking exception to his theoretical views—but without his being offended. And we constantly compared notes together. Each of us, therefore, was interested in the solution of a whole series of problems.^[84]

Graebe's and Volhard's reports from 1862 (cited previously) are consistent with this picture. Guthrie's report from 1854 suggests stronger guidance, even a degree of control, from Kolbe, but it is not inconsistent with these other testimonies. Similarly, V. V. Markovnikov, who studied with Kolbe in Leipzig in 1866-1867, wrote to A. M. Butlerov, then professor at Kazan,

Kolbe was especially attentive to all the workers, and, contrary to expectations, he did not behave like a commanding general at all. On the contrary, he was very glad to discuss and argue, and I have already succeeded several times in locking horns with him. He himself often approached and asked me how one should understand formulas which were not written by his method.^[85]

Alexander Crum Brown also noted that as a student of Kolbe's in 1862 he was "always able to explain any theoretical views of mine to him by first translating them . . . into his language, but I am quite sure he would fail to recognize his own ideas if translated into our language."^[86]

Kolbe emphasized that "in my laboratory I allow everyone who maintains his chemical convictions—which I respect—to continue working in his own direction, and am pleased whenever he obtains the expected results."^[87] When he finally acquired a large laboratory in 1868, he had no trouble filling it to overflowing with admiring students. However intolerant Kolbe may have been to the differing views of colleagues at other universities, he was always indulgent and broadminded with his own students.