Sometimes, the presence of a third party allows two people to accomplish something they either could not pull off, or would take an agonizingly long time to achieve, on their own. We are used to these human mediators, therapists and coaches and advisors, to help us navigate the complexities that one lifetime of experience is just not enough to guide even the best intentioned couple through. As in life, so in chemistry, and the recognition of chemicals that help mediate the reactions of other chemicals has spurred an industry and given humanity broad powers to alter the molecular landscape of our world, for better or worse.
Chemical mediators, or catalysts, play substantial roles in the chemical industry (and in our own individual biochemistries) by allowing reactions to happen quickly and efficiently, and their discovery can be traced back to a woman who carried out fundamental research into the circumstances under which metals can be pulled out of solution and deposited on surfaces that spawned not only the entire concept of a catalyst, but the idea of photoreduction that lies at the heart of photographic technology.
She was Elizabeth Fulhame, and as to when she was born, and when she died, we have utterly no idea. Her life, in so far as it has been transmitted to us at all, is known from her landmark work, 1794’s An Essay on Combustion, from the reaction to that work in the larger chemical community, and from some knowledge of the career of her husband, Dr. Thomas Fulhame. Her parents, her siblings, her hometown, all are details lost to history, replaced with the one reasonably solid conjecture that she was, probably, Scottish. We think.
That one probable fact, however, is an important one, for Fulhame lived in the time when leadership in chemical experimentation was passing from France to Great Britain in the wake of the French Revolution. Lavoisier had been executed, and the French scientific establishment destabilized, and into that vacuum stepped a new generation of English researchers whose names are the common currency of high school students today – John Dalton (1766-1844), Joseph Priestley (1733-1804), and Count Rumford (1753-1814). Together, they picked up where the French chemical pioneers had left off, and presented their findings regularly to a British society increasingly intoxicated by the idea of chemical experimentation as a respectable hobby.
Dr. Thomas Fulhame had studied at Edinburgh University under Joseph Black (1728-1799), a professor of Medicine and Chemistry who we know today for his discovery that, while melting or boiling, the temperature of liquids doesn’t change, which lead to the idea of latent heat, which is a central concept in thermodynamic theory, and for his discovery of magnesium and carbon dioxide. In Black’s classes, Thomas learned that gold could be dissolved by a combination of hydrochloric and nitric acid, and then precipitated back to solid gold via reaction with aqueous ferrous sulfate.
Enter Elizabeth, who in 1780 took this phenomenon as a starting point for an entire research program. She wondered if it would be possible to use the principles of the new chemistry to deposit metals, like silver and gold, onto cloth, and perhaps create a new industry of metal-decorated fabrics, with that procedure. For the next decade and a half, she dedicated herself to investigating that possibility in the face of scientific acquaintances who assured her that she was wasting her time. She tested gold, silver, mercury, platinum, copper, and tin salts using gaseous hydrogen, phosphorous, potassium sulfide, hydrogen sulfide, phosphine, charcoal, and light as potential reducing agents in a series of hundreds of experiments.
Today, we know that when you place soluble metal salts in solution, they separate into positive metal ions and negative non-metal ions, and that the trick to getting those positive metal ions back into solid form is to foist electrons on them to push them back into the neutral state that will allow them to form solid structures again. “Reducing Agents” are chemicals that tend to be good at donating electrons, but they vary in utility depending on what you’re trying to reduce, and under what circumstances, and untangling all of those conditions in an age before anybody knew what electrons even were was a task that could only be approached through dogged persistence and keen observation.
Fulhame never did create a process that had immediate industrial applications, but several of her approaches were fruitful enough that she decided in 1794 to publish an account of her experimental trials to keep others from stealing her methods. That work, An Essay on Combustion, With a View to a New Art of Dyeing and Painting: Wherein the Phlogistic and Antiphlogistic Hypotheses are Proved Erroneous, had within it the seeds of several industries.
In particular, Fulhame described how, when she applied her solutions of metal ions to fabrics, let them dry, and then applied her reducing agents, nothing happened, but that, if she applied the agents before the fabric was dry, a chemical change occurred. She had described, forty years before the term existed, the work of a catalyst, and went on to propose a chemical model whereby water molecules separated and reconstituted themselves over the course of the reaction which highlighted one of our central ideas about catalysts today, namely that they are participants in a reaction that are not consumed in that reaction. It would be twenty years before the action of a catalyst was described by other chemists, and forty years before catalysis received a name, but the roots of this central chemical component were here, in Fulhame’s only published work.
Describing the effect of a catalyst was revolution enough for one work, but Fulhame was hardly done. In offering her own counter-proposal to the phlogiston and anti-phlogiston theories of the time about the nature of combustion (which you can read more about as it affected the life of Marie Lavoisier here), she proposed a two-step process that saw carbon reacting with the oxygen of water to produce carbon dioxide and freeing up hydrogen gas, which then reacted with atmospheric oxygen to produce water, and thereby became among the first researchers in modern chemistry to propose that reactions happen in a series of steps, rather than all at once, what we recognize today as Reaction Mechanisms.
Oh, and she also described a process by which light could serve as a reducing agent for metal salts, including silver nitrate, which is arguably the first instance of images being created through photochemical means, a result significant enough to have been specially mentioned by John Herschel in his 1839 survey of the history of photography as a pioneering step in the field of photographic science.
Multi-step processes, chemical catalysis, and photoreactive imaging – not a bad record of discovery for an individual’s first and only published work. Fulhame’s essay was important enough to appear in German translation by 1798 (the same year she was elected a corresponding member of the Philadelphia Chemical Society), and in an American edition in 1810, but after that date, besides the mention by Herschel in 1839, Fulhame had to wait until 1903 for a thorough-going recognition of the significance of her work by a member of the chemical establishment, when J.W. Mellor wrote a paper on her work. In the last forty years, however, Fulhame’s name has emerged from the realm of the science history specialists, and her work has been celebrated at last for what it was – the sensational debut of the world’s first published woman chemical researcher, moved by her own curiosity, and fearless in the face of the accepted chemical wisdom as she populated the chemical landscape with new characters and behaviors that have enriched the practice of chemistry ever since.
FURTHER READING: If you’ve been reading this column here and there for the past eight years, you probably have an inkling of who I’m going to say is your go-to source here. If it’s a question about the early history of women in chemistry, your first stop has pretty much always got to be the Rayner-Canhams (Marelene and Geoffrey), and in this case they have a nice write-up of her work in their Women in Chemistry: Their Changing Roles from Alchemical Times to the Mid-Twentieth Century (2001). Their work forms the basis of most accounts you’ll find online, but this one by Claire Jarvis for Physics Today does good work in going beyond the framework the Rayner-Canhams laid down as she expands the story of catalysis after Fulhame’s initial contributions.
Lead image: Title Page from ‘An Essay on Combustion’ by Elizabeth Fulhame. Printed for the author, by J. Cooper, 1794. Science History Institute, Public Domain, via wikimedia.