In the middle years of the 1890s, the world was trembling on the brink of breakthroughs and breakdowns, and so was the no-longer-quite-young chemist, Svante Arrhenius. The Victorian age, with its optimistic complacency and its Pax Brittanica, was drawing to a close. The Colonial system was entering the first, barely perceptible, stages of breakdown as Britain fought the bloody Boer War in southern Africa; the German Kaiser’s jeers from the sidelines—and still more the German challenge to British naval superiority—was forcing a political realignment that would set the sides for the First World War. And the Steam Age was beginning its metamorphosis into the Oil Age.
As to Arrhenius, he was entering well and truly into middle age—though still regarded as a “young Turk” by many of his elders in the world of chemistry. He had overcome the obstacle put in his way when his Doctoral dissertation received the lowest possible passing grade in 1884. His examiners had not understood that his ideas about ionic dissociation in solutions would become essential to the development of chemistry over the following decades; nor could they envision the Nobel prize which he would later win. (Indeed, Nobel prizes did not yet exist.) With limited prospects, but convinced of the correctness and importance of his concepts, Arrhenius had done six years of postdoctoral study, traveling widely across Europe and sharing his ideas with receptive researchers. His reputation slowly increased, and he was finally able to take a position as a lecturer in Stockholm in 1891.
One of his students was Sofia Rudbeck. She was beautiful and gifted--one of the first Swedish women to obtain a Bachelor’s degree in science--and became the first female member of the Geological Society of Stockholm. She and Arrhenius were married in 1894. The following year, Arrhenius was promoted to a Professorship, and perhaps it seemed to him that his life was unfolding as it should. As is so often the case, things would not be quite so simple; one of the pending breakdowns would be that of his marriage, and it would be intimately tied to a breakthrough in the science of climate change.
Langley's "Aerodrome" at his museum, The Smithsonian
One of the most striking of all the pending breakthroughs, though, would be in the development of powered flight. Of course, the Wright brothers’ first successful flights were still nearly a decade in the future--but Samuel Langley had his greatest aeronautic success in the mid-90s. Langley was director of the Smithsonian Institution, and a prominent scientist. As with many nineteenth-century savants, his interests were diverse, but he spent fifteen years and considerable sums of money—some his, some coming from the US Department of Defense—with the object of achieving human flight.
As the picture shows, he came close. The flight took place on May 6, 1896, above the Potomac River. The “aerodrome,” as Langley called his flying machine, was an unpiloted model, and is credited as "the first powered heavier-than-air machine to attain sustained flight." On this occasion its flight covered a circular path of approximately 3,300 feet. It is telling that the photo was made by Langley’s colleague, Alexander Graham Bell—the man who invented the telephone! Such was the interest aroused by Langley’s experiments.
Another, earlier part of Langley’s work affected Arrhenius deeply during the dark days of 1895. The intensity of his romance with Sofia had burned out, leaving the reality of two deeply incompatible personalities. She—by now carrying their son, Olof—left him, to live alone on an island near Stockhom, writing letters telling Arrhenius how much happier she was without him.
He was fortunate to have an engrossing task to help carry him through the stresses of separation and divorce. His work on ionic chemistry was by this time reaching widespread scientific acceptance—though the complete victory of “the ionists” was still in the future. But basically the battle was won, and now he needed something else to do, scientifically speaking.
The new problem turned out to be the development of a chemical solution to a geological problem. It is tempting to speculate that Sofia’s geological interests may have had some connection with his choice, but the known connection is with Arrhenius’s friend, the geologist Arvid Högbom. Högbom was interested in what we now call the carbon cycle—the movement of carbon between ocean, atmosphere, biosphere, and the earth’s crust. He believed (correctly, but not in accordance with then-prevailing ideas) that atmospheric concentrations of CO2 might have varied widely over geological ages.
Following up on this insight, Arrhenius posed this research question: how much variance in atmospheric CO2 levels would be necessary to account for the dramatic changes in glaciation that paleogeologists had discovered? In other words, could CO2 account for the ebb and flow of the ice ages?
Uppsala images, courtesy Wiki Commons.
Arrhenius approached this question in a manner that turned out to be characteristic of his later work. Born February 19, 1859, at Vik, near Uppsala, Sweden, he had taught himself to read by the age of three, and had also grown up watching his father--a surveyor and overseer--use large tables of numbers in his work. The younger Svante had either developed or inherited a great facility in remembering, manipulating, and understanding numerical representations of real-world phenomena. Arrhenius's main researches in electrolytic chemistry showed him also to be an experimenter capable of meticulous and patient lab work--but from the mid-1890s he would frequently choose to reanalyze data obtained by others.
In this case, he would choose Samuel Langley’s observations of the spectrum of moonlight.
Samuel Pierpont Langley
Langley--born in Roxbury, Massachusetts, in 1834--was an astronomer by trade. He had trained at the Harvard Observatory and taught at the Naval Academy, and in 1867 became the director of the Allegheny Observatory. He is credited with initiating the first true research programs there. He also raised money to support the Observatory by creating a commercial subscription time-standard used by railroads and distributed via telegraph.
His last major research initiative there, before he became head of the Smithsonian Museum, consisted of investigation of the temperature of the Moon. As part of this project he published a paper detailing infrared band observations made by himself and Frank Washington Very from 1885 to 1887. Because these observations, made at different places and times, involved transit of various wavelengths of infrared radiation through longer and shorter paths through the atmosphere, Arrhenius was able to use them to tease out the atmospheric absorptivity of CO2 over varying conditions.