This Month in Physics History

August 1856: Eunice Foote Concludes That Carbon Dioxide Could Warm the Atmosphere, Three Years Before John Tyndall Did

Well over a century later, female historians rediscovered Foote’s work — and were themselves overshadowed.

By Tess Joosse | July 13, 2023

Credit: Drawing by Carlyn Iverson / NOAA Climate.gov

Eunice Newton Foote

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In 1856, an American woman named Eunice Newton Foote conducted a series of homespun experiments. She set up 30-inch-long cylinders, each with a thermometer inside, and each filled with different gases and gaseous mixtures — moist air, dry air, carbon dioxide, oxygen, and hydrogen. Foote placed the cylinders in the sun and charted how the gases warmed. The cylinder containing carbon dioxide warmed the most, she noted, and stayed at its high temperature for a long time after she took it out of the sun.

Foote wrote up these data into a short paper with a stunningly prescient conclusion. Of carbon dioxide, she wrote: “An atmosphere of that gas would give to our earth a high temperature,” describing the phenomenon we now call the greenhouse effect, the main cause of climate change. The paper, titled “Circumstances Affecting the Heat of the Sun’s Rays,” was presented at a meeting of the American Association for the Advancement of Science (AAAS) on Aug. 23, 1856.

Then Foote and her work faded into obscurity. The Irish physicist John Tyndall, who reached similar conclusions from more intricate experiments three years later, is widely regarded as the discoverer of the greenhouse effect and the father of climate science.

But Foote wasn’t wholly forgotten. Starting in the 1970s, several female historians of science identified Foote as one of a class of nineteenth-century women who were educated and who “too shared in the popular enthusiasm for science which emerged” in pre-Civil War America, as historian Deborah Jean Warner wrote in 1978. But these historians did not yet connect Foote’s work to the issue of climate change.

It was a geneticist and women studies scholar named Elizabeth Wagner Reed who recognized the importance of Foote’s results. In her 1992 book American Women in Science Before the Civil War, Reed affirmed that Foote “demonstrate[ed] what we call the greenhouse effect today and is a phenomenon which is of concern to us even now.”

Reed’s own contributions to science were obscured for many years. Among the first researchers to study evolution in the fruit fly Drosophila, one of the most widely used model organisms in science today, Reed worked on studies in tandem with her husband. Though he himself acknowledged her contributions, she received little public recognition.

“Elizabeth Reed encountered and resisted sex discrimination throughout her career,” wrote her daughter Catherine in an afterword to the 1992 book. “She researched and wrote this book to refute the claim that there had never been women scientists.”

Indeed, there had long been women scientists, including Foote. Born Eunice Newton on July 17, 1819, in Connecticut, she grew up in New York state and attended the Troy Female Seminary, the first institution of higher education for women in the United States. Here, Foote and other attendees studied languages, philosophy, and mathematics. They also were permitted to take science courses taught in novel hands-on laboratories at the nearby Rensselaer School (now Rensselaer Polytechnic Institute).

In 1841 she married a patent lawyer named Elisha Foote, and the couple moved to Seneca Falls, New York. There they befriended Elizabeth Cady Stanton, a prominent leader in the women’s rights movement. Both Eunice and Elisha attended the landmark Seneca Falls Convention in July 1848 and signed its resulting “Declaration of Sentiments,” which critiqued gender inequality and proclaimed women’s inalienable rights.

Along the way, Foote began conducting experiments in a home laboratory. Her gas-heating experiments might have been inspired by Joseph Henry, a family friend and director of the Smithsonian Institution, says John Perlin, a visiting scholar at the University of California, Santa Barbara, who has written about Foote. Henry was interested in how weather and climate impacted agriculture, Perlin explains.

After Foote wrote up her results, Henry read her paper aloud at the AAAS meeting in Albany on Aug. 23, 1856. While the AAAS allowed women to be members and did not prohibit them from presenting work, it seems to have been uncommon for them to do so. The research — and Eunice’s gender — received some attention in the press: A writeup in Scientific American proclaimed, “the experiments of Mrs. Foot [sic] afford abundant evidence of the ability of women to investigate any subject with originality and precision.”

Foote’s work was also summarized in The Annual of Scientific Discovery, an anthology published in 1857. But it appeared that those who knew of her results did not know what to make of them, including Henry. According to a write-up of the AAAS meeting in the New York Daily Tribune, Henry said “that although the experiments were interesting and valuable, there were … difficulties encompassing any attempt to interpret their significance.” Foote’s paper was then published in the American Journal of Science and Arts under Eunice’s own name, alongside a paper by Elisha, also an amateur scientist.

Foote did present her own research at the following year’s meeting, reading a paper on static electricity. This work was the last publication of Foote’s scientific career, though she filed patents for several inventions, including a rubber sole to silence squeaking shoes and a paper-making machine, before her death in 1888.

Tyndall, the erstwhile originator of climate science, casts a shadow over Foote’s story. While her contributions gathered dust, the well-connected and highly educated Tyndall measured the gases’ absorption of heat with a spectrophotometer and publicized his results. Did he know about Foote’s work, or even plagiarize it? Historians are at odds. Tyndall was on the editorial board of the Philosophical Magazine, which republished the paper by Elisha Foote that was printed alongside Eunice’s, and Tyndall was known to believe women were less intellectually capable than men. Still, others argue that Tyndall set up his experiments in a manner totally independent of Foote’s results, and there’s no record of Tyndall mentioning either Foote in any records or correspondence.

Modern experts do agree, however, that Foote’s experiment only measured warming from visible radiation and not infrared radiation, which we now know emanates from Earth to cause the greenhouse effect. Tyndall’s more state-of-the-art experiments did.

In 2011, retired petroleum geologist Ray Sorenson, an avid collector of historical science books, happened across the summary of Foote’s work in The Annual of Scientific Discovery. He published a paper noting her role as a climate pioneer, kicking off a cascade of appreciations. A retrospective obituary published in 2020 in The New York Times called her experiment “ingenious.”

Reed had recognized this innovation decades earlier. “The work she did publish reveals her interest in scientific problems of large dimensions … [and] shows that she had the attributes of a good research scientist,” she wrote of Foote. “Whatever the reasons, her abandonment of scientific investigation resulted in a real loss to science of a gifted research mind.”

Tess Joosse is a science journalist based in Madison, Wisconsin.

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May 1962: James West and Gerhard Sessler Patent the Electret Microphone (APS News, May 2023)

April 1986: Bednorz and Müller Trigger Avalanche of High-Temperature Superconductivity Research (APS News, April 2023)

March 1966: The First Human-Made Object Makes Impact With Another Planet (APS News, March 2023)