Eunice Newton Foote and the Greenhouse Effect

Eunice Newton Foote, linocut, 9.25" x 12.5" by Ele Willoughby, 2025

Once again, I am taking part in the Printer Solstice collection of printmaking prompts, starting at the winter solstice (here in the northern hemisphere). The prompts this year are mathematical in scheme, which works well for me, and my on-going series of portraits of women in STEM. The first prompt, "addition" made me think of the greenhouse effect, excess additional atmospheric CO2 and the resulting excess terrestrial temperatures. It made me think of a scientist who has been on my to do list for years: Eunice Newton Foote. The reason I have not tackled her portrait is that there are no known photographs of Eunice Newton Foote. I had hoped, since I knew that climate scientist Katherine Hayhoe and historians of science and others were seeking her portrait, that perhaps I should just wait patiently. As time wore on, we have learned more about Foote's life, but her portrait has not been found. However the waters have been muddied, as more and more people illustrate their posts and even published newspaper articles with images incorrectly labelled as Eunice Newton Foote. So I decided it was my time to add my image of her, to offer another imagined illustration, based on what we do know, rather than misinformation. It's quite easy to get the wrong photograph associated with a little-known historical woman in science, so I can understand how this has happened, but it frustrates me. Eunice Newton Foote deserves to be remembered as a scientist, inventor and activist, and she deserves not to be conflated with her daughters, or worse, random historical women and AI-generated nonsense.

My lino block print portrait shows the amateur pioneering American scientist, inventor and women's rights advocate Eunice Newton Foote (1819-1888) who did the earliest experiments to show the insulating effect of certain gases and correctly concluded that increasing carbon dioxide levels would affect atmospheric temperature and climate, which we now call the Greenhouse Effect. Each print is burnished by hand on lovely cream-coloured Japanese paper, 9.25" x 12.5" in a gradient of cyan, pale blue and bronze.

This is Mary Foote Henderson, again. She is not her mother.
This is specifically a detail of a photo by the Brady Studio. 
Record Unit 7075 - The Henderson Family Papers, 
1868-1923, Smithsonian Institution Archives. 
You can check for yourself.

Eunice Newton was born in Connecticut to Thirza and farmer and entrepreneur Isaac Newton Jr., a distant relative of famed physicist Sir Isaac Newton, who had six sons and five other daughters (though girl died at two years of age). They moved the family to Ontario County in western New York, which was a centre of social activism for abolitionists, dress reform activists, mystics, temperance advocates, and women's rights campaigners. She attended the Troy Female Seminary, a women's preparatory school established by feminist Emma Willard, which offered a much broader curriculum than the typical women's finishing school and where students were actually encouraged to attend science courses at the nearby Rensselaer School, run by a scientist, education innovator and proponent of women's education Amos Eaton. Eaton introduced practical experimentation in the lab alongside teaching theory.

In 1841 Eunice married lawyer Elisha Foote, who trained in Johnstown, New York, under Judge Daniel Cady, the father of women's rights activist Elizabeth Cady Stanton. Elisha bought a house, then deeded it to Cady who gave it to his daughter. Elisha became a judge in Seneca County, but resigned in 1846. Eunice was friends with Elizabeth Cady Stanton and attended the 1848 Seneca Falls Convention, the first women's rights convention. She and Elisha both signed the Declaration of Sentiments, described by Frederick Douglas as the "grand movement for attaining the civil, social, political, and religious rights of women." Eunice was one of the five women who prepared the convention proceedings for publication.

Eunice and Elisha both worked as inventors. Elisha filed a patent in 1842 on a thermostatically controlled cooking stove invented by Eunice presumably because as a married woman, Eunice would have been unable to defend her patent in court. Eunice told Elizabeth Cady Stanton she thought half of all patents filled were in fact inventions by women with the patents taken out by men. In fact, in 1857, Elisha defended the patent and got a substantial settlement for infringement.

Mary Foote Henderson, not her mother.

Elisha went back to working as a lawyer, and Eunice built a lab in their home. The pair had two daughters: writer, developer, suffragette and social activist Mary who became known as "The Empress of Sixteenth Street" and writer and naturalist Augusta, who wrote The Sea-Beach at Ebb-Tide, regarded as a seminal work on the intertidal biology of the United States. The family moved to Saratoga Springs, NY, where Elisha specialized in patent law, then became the Commissioner of Patents, then served on the Board of Examiners-in-Chief for several years.

In her lab Eunice investigated the effect of sunlight on various gases. Using two glass cylinders, each equipped with two mercury-in-glass thermometers, she used an air pump to evacuate the air from one cylinder and compress it in the other cylinder. When their temperatures equalized she placed them both in the sunlight and looked for temperature variances. She contrasted this with when the cylinders were placed in the shade and also tested the temperature results by dehydrating one cylinder and adding water to the other, to measure the effect of dry versus moist air. She noted that the amount of water in the air did affect the temperature. She tried this experiment using air, carbon dioxide (then known as carbonic acid gas) and hydrogen. The cylinder of carbon dioxide in sunlight became hotter than the others. She wrote: "The receiver containing this gas became itself much heated—very sensibly more so than the other—and on being removed [from the Sun], it was many times as long in cooling". Considering the history of Earth, she wrote, "An atmosphere of that gas would give to our earth a high temperature; and if, as some suppose, at one period of its history, the air had mixed with it a larger proportion than at present, an increased temperature from its own action, as well as from increased weight, must have necessarily resulted." She clearly understood and expressed the impact of increased atmospheric carbon dioxide and what we now call the Greenhouse Effect. She submitted these findings as a paper entitled "Circumstances Affecting the Heat of the Sun's Rays", that she submitted for the tenth annual AAAS meeting, held on August 23, 1856, in Albany, New York, where it was presented by physicist Joseph Henry on her behalf. While not published in the proceedings of the AAAS meeting, it was published in the 1856 edition of the American Journal of Science and Arts; it was the first known physics publication in a scientific journal by an American woman. Summaries were also included in several international scientific journals and periodicals. Eunice was praised in the September 13, 1856, issue of Scientific American for backing up her theories with experiments, noting "she was deeply acquainted with almost every branch of physical science"

C'mon people. This one is literally labelled

Mrs. Henderson. It's a photo by Ida

Hindman in 1895, for the Washington

Sketch Book.

Eunice's experiment was not without precedent.  In the 1770s, Horace Bénédict de Saussure found that altitude impacted solar heat in an enclosed cylinder and the 1820s Joseph Fourier theorized that atmospheric gases trapped solar heat. But only Eunice Foote had drawn the conclusion that solar heat would be increased by the presence and proportion of C02 or water vapour in the atmosphere. Three years after Foote's publication, in 1859, physicist John Tyndall performed a more sophisticated experiment which showed several gases both trapped and emitted infrared thermal radiation rather than simply investigating the effect of sunlight. He published "Note on the Transmission of Radiant Heat through Gaseous Bodies" in the Proceedings of the Royal Society, where he cited Claude Pouillet's work on solar radiation through the atmosphere, but did not cite Foote's work. It's unclear if he failed to note her results or did not see their relevance. He did not mention water vapour, carbon dioxide, or climate until several publications later. A very skilled and well-trained (though regrettably quite chauvinistic) physicist, Tyndall is often credited with the earliest evidence of the Greenhouse Effect. Alternatively, the Greenhouse Effect is sometimes credited to physical chemist Svante Arrhenius, who in 1896, used physical chemistry to estimate how much atmospheric CO2 would increase the Earth's surface temperature. There is no denying though that Eunice Newton Foote was the first to specifically argue that our climate would warm with increasing atmospheric CO2.

Foote went on to investigate moisture content and which gases in the air could generate static electricity. She hypothesized that electric charges and fluctuations in atmospheric pressure might explain the Earth's magnetic field and polarity, which we now know is not the case. Her paper "On a New Source of Electrical Excitation" was read by Henry at the 1857 AAAS meeting in Montreal, and published in the Proceedings of the American Association for the Advancement of Science, the first physics publication there by an American woman. 

In 1860 Eunice filed a patent in her own name for a shoe and boot insert made of a single piece of vulcanized rubber to "prevent the squeaking of boots and shoes". In 1864 she developed a new cylinder-type of paper-making machine. In 1868 she invented skates without straps. 

She died in 1888 in Lenox, Massachusetts. She fell into obscurity until historians began researching early women scientists in the 1970s and more recently, climate scientists have revisited and worked to highlight her early contributions to their science.

As her story has been rediscovered people have made a concerted effort to find images of her. Though there are many photographs of her two daughters, especially Mary Foote Henderson, and Augusta Newton Foote Arnold, and her husband Elisha Foote Jr, there are no known photographs, or painted portraits of Eunice. Many stories, including in published newspaper stories, are illustrated with photographs of Mary misidentified as Eunice, or worse, with AI-generated slop images based on completely unrelated women. All we have, so far, is her 21 July 1862 passport application, where she is described as having an oval face, dark brown hair, blue-grey eyes, a small ordinary chin, an ordinary nose, a full forehead and a rather large mouth. Having looked at these photos carefully, I have convinced myself that Mary resembles her father, so I don't even think we can rely on family resemblance and let Mary's image give us an idea of what Eunice looked like. So I chose to illustrate her, without showing her full face, at work in her lab, in Victorian clothing like what other women doing similar work. Her paper describes her experiments with air pump, and two large cylinders with two thermometers each, so I could illustrate these as described.

References

Augusta Foote Arnold, Wikipedia, accessed December, 2025

Elisha Foote, Wikipedia, accessed December, 2025

Eunice Newton Foote, Wikipedia, accessed December, 2025

Foote, Eunice. "Circumstances Affecting the Heat of the Sun's Rays". The American Journal of Science and Arts. 22 (66). New York, New York: G. P. Putnam & Company: 382–383. ISSN 0099-5363. OCLC 1280516952. September, 1856.

Foote, Eunice. "On a New Source of Electrical Excitation". Proceedings of the American Association for the Advancement of Science: Eleventh Meeting. Cambridge, Massachusetts: Joseph Lovering: 123–126. OCLC 923936325.  August, 1857.

Huddleson, Amara. Happy 200th birthday to Eunice Foote, hidden climate science pioneer,  Climate.gov, July 17, 2019.

Josse, Tess. August 1856: Eunice Foote Concludes that Carbon Dioxide Could Warm The Atmosphere, Three Years Before John Tydall Did, APS News, July 12, 2023. 

Kurland, Zoe, Katie Hafner, Elah Feder and The Lost Women of Science Initiative, The Woman Who Demonstrated the Greenhouse Effect, Scientific American,  November 9, 2023.

Mary Foote Henderson, Wikipedia, accessed December, 2025

McNeill, Leila  "This Lady Scientist Defined the Greenhouse Effect But Didn't Get the Credit, Because Sexism". Smithsonian. Washington, D.C.: Smithsonian Institution. ISSN 0037-733December 5, 2016.