Chemistry, Microscopy, and the Nanoworld

Chamot met Behrens at the Polytechnicum in Delft. Behrens, a mineralogist, had adapted his microscopic research to metallurgy, organic chemistry, and biology. According to legend, in parting Chamot asked how he could thank Behrens, to which the older man suggested he teach chemical microscopy at Cornell—sparking a six-decade tradition in Ithaca.When he returned Chamot headed the Cornell chemistry department’s Division of Sanitary Chemistry, Toxicology, and Microchemical Analysis. At this point Chamot considered microscopy an adjunct to his work on safe water supplies. But through this path Chamot became entangled in local politics. By 1901 his findings on Ithaca’s poor water quality led him to charge the city with negligence. This was dangerous territory: another Cornell chemistry professor, A. A. Breneman, lost his job in the 1880s when his unfavorable review of water quality in Ithaca and nearby Geneva raised the ire of local business owners. Likewise, Chamot’s pleas were ignored, and in 1903–1904 typhoid swept Ithaca, leaving over 1,300 sick and more than 80 dead in a town of only 15,000. The cause was traced to residential sewage running into the city’s water supply, exactly as Chamot had warned. Yet, though he had been finally, and tragically, proven right, the soft-spoken Chamot abhorred the dangerous and thankless role of a scientific Cassandra in local politics.

Instead, Chamot rededicated himself to educating and interesting his students and colleagues in “chemical microscopy.” By 1900 he was teaching courses on organic and inorganic microscopical analysis; after 1914 he turned to the microscopy of metals, alloys, and materials of construction. We sometimes forget how much steel manufacturing, which drove innovation in America from railroads to skyscrapers, was the chemical industry of its day. Steelmaking involves mixing iron with chemicals to add or remove trace elements, from standard carbon to exotic silicon and vanadium, and changing temperature and pressure and physically manipulating the metal to rearrange the grains and introduce or eliminate defects to produce desired characteristics. Chamot had his greatest influence in systematically developing microscopy to study this microstructure. Chamot used his microscopy courses to offer future industrial chemists a strikingly visual illustration of how processes like crystallization, sintering, and phase changes proceed.

Many of the lessons of these courses were presented in Chamot’s celebrated 1915 book Elementary Chemical Microscopy and its sequel (co-written with his protégé Clyde Walter Mason) Handbook of Chemical Microscopy (in print as late as 1983). Chamot established a new war-related field by studying the microstructure of firearms, writing The Microscopy of Small Arms Primers in 1922. Appropriately enough, this book echoed Sorby’s work in two ways: in appealing to local industry (here, the manufacturer Ithaca Gun) and in pioneering chemical microscopy for forensics. Sorby, inspired by Bunsen and Kirchhoff, had combined lenses with prisms to invent a spectroscopic microscope that could identify different mineral species in a rock slice. In 1865 Sorby used this method to identify whether minute stains included blood—a technique that actually saw use (though inconclusively) in an 1871 trial.

Postwar: Tom Anderson to Nanotechnology

By the time Chamot retired in 1938, light microscopy had for the first time been joined by a non-optical means of magnification—the electron microscope. Experiments to focus electrons and magnify an object first arose in the early 1930s. Ernst Ruska (who received the 1986 Nobel Prize in Physics) and Max Knoll in Berlin, Günther Rüdenberg at Siemens, and Ernst Brüche at AEG all published in 1931, followed quickly by (among others) Ladislaus “Bill” Marton in Brussels and James Hillier and Albert Prebus at the University of Toronto. By the outbreak of war Marton and Hillier were each separately competing to have their designs commercialized in the United States by RCA. Anxious to have its television technology accepted by the Federal Communications Commission as the standard for commercial broadcasting, RCA promoted electron microscopy. Since electron microscopy and television are closely related, RCA could use dazzling scientific discoveries made with its microscopes to assert the superiority of its televisions.

RCA therefore desperately cultivated customers and uses, particularly in the publicity-friendly areas of biology and medicine. RCA’s director of electronics research, Vladimir Zworykin, hired a young chemist, Thomas Foxen Anderson, to liaise with new users and develop new applications for the microscope. Anderson earned an undergraduate degree in chemistry at Caltech in 1932 and, like Chamot, made a scientific pilgrimage to Europe, where he spent a year developing a new spectrograph. Upon returning he enrolled in the Caltech chemistry department’s Ph.D. program, where he delved into Raman spectroscopy under Don Yost and Linus Pauling. Then followed a long time in the Depression-era job market: from Caltech to a postdoc in surface chemistry, then to the botany department at the University of Wisconsin, and back to teaching chemistry, still at Wisconsin.

When Anderson landed a National Research Council–RCA postdoctoral fellowship in 1940, it seemed like another job in the string. Yet this position would mark a revolutionary turning point for Anderson and for electron microscopy. Working from the RCA labs in Camden, New Jersey, Anderson reported to a distinguished committee of cytologists, virologists, geneticists, and bacteriologists, including Stuart Mudd, Wendell Stanley, and Milislav Demerec. The committee made Anderson’s work a priority and delivered specimens from their labs; Anderson then developed ways to image those specimens and co-published a series of papers with committee members. RCA publicized the work, thereby attracting new researchers to electron microscopy. Soon biologists of all stripes were sending Anderson samples or signing up for electron microscopy time at RCA. Meanwhile, he continued developing new ways to prepare specimens and interpret his own images. As historian of science Nicolas Rasmussen puts it in his 1997 book Picture Control, “through the [RCA] committee’s exercise of power, Anderson’s [specimen preparation] techniques, his aesthetic standards, and his style of interpretation all became models and benchmarks for the work of biological electron microscopists” (p. 54). Anderson, the itinerant chemist, now became the arbiter of a powerful new technique, eventually establishing a renowned program at the University of Pennsylvania.

Still, Anderson’s clients were biologists, not chemists. In the postwar instrumentation revolution that transformed chemistry, microscopy had little impact. Spectrometers, diffractometers, ultracentrifuges, and analyzers all framed the new chemistry, but not microscopy—this despite a remarkable proliferation of ways to image the microworld. Electron microscopy soon segregated into two techniques: transmission electron microscopy (where the beam passes through a thin sample) and scanning electron microscopy (where the beam is rastered over and scattered by a sample). In the 1950s Erwin Mueller at Penn State developed the field emission and field ion microscopes. The field ion microscope could actually image individual atoms arranged in a metal sample; later field ion studies showed diffusion of adsorbates on metal and pictures of single molecules. The 1970s saw the arrival of scanning acoustic microscopy and the first nearfield scanning microscopes.

Ultramicroscopy and chemistry only began to borrow from each other at 17th- century levels after the invention of the scanning tunneling microscope (STM) and its cousin, the atomic force microscope (AFM), in the 1980s. As with electron microscopy, chemists rarely built their own STMs and ATMs, but they developed new and popular uses for them—including those that would breathe life into the idea of nanotechnology. The STM was invented in 1981 by Gerd K. Binnig and Heinrich Rohrer, physicists at the IBM laboratory in Zurich who shared the 1986 Nobel Prize in physics with Ruska. Initially they used the new device to characterize advanced microelectronic components, expanding a previous generation’s use of electron microscopy to understand how new ways of preparing photoresists and etching and cleaning silicon actually affected circuit features. But Binnig and Rohrer soon started using STMs to create basic knowledge about various materials. As physicists from the field of low-temperature electron tunneling, however, they knew little about chemistry and materials science. They therefore formed partnerships with colleagues from surface science and electrochemistry to allow STMs to flow into those communities.

The STM could “see” individual atoms, but the question for all early STM builders was what atoms to look at. In providing the answer, chemists redefined how we think about and represent molecules. The collaboration that produced perhaps the most visually striking results was at IBM Almaden, where a physicist, John Foster, teamed with an organic chemist, Jane Frommer, to produce some of the first STM work to visualize molecules. Foster was using an STM to inspect graphite but saw that his images showed contamination on the surface; he asked Frommer to work with him to understand these contaminants, and she suggested they study organic molecules intentionally deposited on graphite, such as dioctyl phthalate. Eventually they learned to “herd” these molecules with the STM and even to give them a voltage pulse to “dissect” them—that is, to perform a chemical reaction by hand.

This work made Foster and Frommer popular with the early proponents of a new idea called nanotechnology. Its supporters wanted to build materials from the “bottom-up”—using physical probes like the STM and AFM to manipulate chemical reactions and make structures with every atom in a specially selected place. This idea is still far off and may never be achieved. But the ability to use physical devices to manipulate and image chemical processes at the atomic level is here to stay. Microscopy and chemistry cooperate today because, at last, they can do what the early microscopists hoped: see “corpuscles” at work and see how their shape, size, and arrangement do indeed affect bulk material properties. Nanotechnology flourishes at the intersection of new chemical objects—buckyballs, quantum dots, dendrimers—and the instruments that can see and move them.

For Further Reading

Barnett, James A. “A History of Research on Yeasts 1:Work by Chemists and Biologists, 1789–1850.” Yeast (1998), 1439–1451.

Gooday, Graeme. “‘Nature’ in the Laboratory: Domestication and Discipline with the Microscope in Victorian Life Science.” British Journal for the History of Science (1991), 307–341.

Higham, Norman. A Very Scientific Gentleman: The Major Achievements of Henry Clifton Sorby. Oxford: Pergamon Press, 1963.

Mason, Clyde Walter. “The Services of Émile M. Chamot to Chemical Microscopy.” Industrial and Engineering Chemistry Analytical Edition (1939), 341–343.

Rasmussen, Nicolas. Picture Control: The Electron Microscope and the Transformation of Biology in America, 1940–1960. Stanford, CA: Stanford University Press, 1997.

Wilson, Catherine. The Invisible World: Early Modern Philosophy and the Invention of the Microscope. Princeton, NJ: Princeton University Press, 1995.