Ellen Gleditsch (1879–1968) was a Norwegian radiochemist who spent her career pursuing precision in an imprecise world – measuring the radioactive decay of radium with such exactitude that her 1915 determination remained the standard for decades, whilst simultaneously building international networks that enabled women scientists to work abroad when institutions barred their way. Her dual legacy – as both an exacting experimentalist and a resolute advocate – reveals a less celebrated truth about scientific progress: that rigour and justice are inseparable when those expected to do the work are denied credit for it. This conversation takes place today, nearly sixty years after her death, in a space where her insights about science, resilience, and institutional change remain urgently relevant.
Dr. Gleditsch, thank you for meeting me today. I must begin by saying that many people in the modern scientific community know Marie Curie’s name intimately, but yours remains far less visible – despite five years of work in her laboratory. How do you regard that particular erasure, looking back?
Ah, you begin with the wound that never quite closes. Yes, well. I do not say this with bitterness, you understand – bitterness is for those who had other paths available to them. But the attention paid to Madame Curie was, I think, rather like looking at a star and forgetting the entire constellation around it.
When I arrived at the Institut du Radium in 1907, I was twenty-eight years old. I had trained as a pharmacist because Norwegian universities would not permit women to study chemistry formally. I had taught myself through apprenticeship, through persistence, through working – always working. And in Paris, I performed fractional crystallisations of radium for five years. My hands became stained with radioactive salts. The work was tedious beyond description. You stand at a glass-topped bench, crystallising, filtering, weighing, crystallising again. Thousands of times. Millions of individual manipulations. Few could do it. We did not have the protective equipment you have now; we did not understand the danger. But we understood precision.
The thing that was odd – and this I have thought about for many years – is that this exacting work was considered less valuable than the theories that emerged from it. Madame Curie would write her papers, present her ideas, and the world attended. I would purify the substances that made those papers possible, and I was paid nothing. My laboratory fees were waived because no one else wanted to do the work. One might think that would make my contribution obvious. Instead, it made me invisible.
You mentioned your own quote once – about working with someone who reputedly hated women. You said he expressed surprise that you didn’t “scream.”
Ah yes. I have kept that comment my entire life, turning it over in my mind like a stone. “She does not scream.” As though competence were measured by silence. As though the absence of complaint were itself a remarkable achievement. I heard this months after he said it – someone passed it along as a kindness, as a compliment. I realised then how very low the bar was set. We were not required to be brilliant. We were simply required to be quiet and to endure. And if we did so, with a mild expression and careful hands, we were exceptional.
It has always made me sad because it revealed so clearly the true problem: not the lack of women’s capacity, but the smallness of the expectations. When a man solves a difficult problem, he is called a chemist. When a woman solves the same problem silently, without complaint, without demanding credit, she is called rare.
Let’s turn to Yale, 1913. This is perhaps the moment most loaded with irony – you were rejected by both institutions you approached, yet you went anyway. Can you walk me through that decision and what you actually did when you arrived at Bertram Boltwood’s laboratory?
This requires some context. I had secured a fellowship from the American-Scandinavian Foundation – a modest sum, but sufficient. I had earned my licenciée from the Sorbonne in 1911, which was equivalent to a master’s degree. I had five years of unpaid work in the world’s preeminent radiochemistry laboratory. And still, two American universities turned me away.
I was not naive about this. I knew it was not about my qualifications. It was about my gender, and perhaps also about their uncertainty regarding women’s capacity to contribute original research. So I made a decision that seems rather bold now, though at the time it felt simply necessary: I went anyway.
I wrote to Dr. Boltwood directly. I did not ask his permission, you understand. I stated my credentials plainly. I said I had secure funding. I said I wished to work on the problem of radium’s half-life. I said I would arrive in October 1913. And then I arrived.
Boltwood’s initial reaction – I learned this years later through correspondence – was not enthusiastic. He wrote to Ernest Rutherford complaining about Mlle. Gleditsch appearing with a fellowship from “a foundation I never heard of.” He wondered whether she was qualified. He worried about the distraction of having a woman in the laboratory. He was not rude to me personally, but his reluctance was palpable.
What changed his mind?
The work. The measurements began to come through. Radium’s half-life was crucial – absolutely crucial – because it served as the reference standard for all radioactivity measurements in that era. Every calculation in nuclear science depended upon knowing this value precisely. Boltwood had been using older estimates, some of which were quite poor. My measurements, which began accumulating through late 1913 and into 1914, were remarkably consistent. I employed gravimetric analysis and extremely careful sample preparation. The errors were minimal.
By the time we published in 1915, Boltwood had become a collaborator rather than a reluctant supervisor. We shared authorship. And more than that – and this matters – he never again expressed doubt about women’s capacity in radiochemistry. He became, in fact, rather a quiet advocate. People change when confronted with evidence they cannot dismiss.
My value for radium-226’s half-life was approximately 1,600 years. Modern measurements confirm this was remarkably accurate. For decades, every radiation therapy protocol, every nuclear physics calculation, depended on this measurement. It is perhaps the most concrete legacy I left: a number so precise it required no revision for half a century. That is the power of meticulous experimental work. One cannot argue with numbers obtained carefully.
I’d like to understand the technical methods more deeply. Can you explain the gravimetric approach you used to determine this half-life, as though speaking to a contemporary specialist?
Ah, now we speak the language that matters most to me.
The challenge was this: radium decays by emitting alpha particles, transforming into radon gas. The fundamental principle is that if you know the rate of decay – what we call the specific activity, the activity per unit mass – you can calculate the half-life. The half-life is the time required for half of any quantity of radium to decay.
What we measured was the ratio between the mass of radium present and the activity – the rate at which it was emitting radiation. The activity we determined through electrical measurement. We used an electrometer, which detected the ionisation produced by the alpha particles. This ionisation current is proportional to the number of disintegrations occurring per second. With careful calibration and repeated measurements, one obtained a very precise value for activity.
The mass we determined gravimetrically – weighing the radium salt on an analytical balance. But here was the difficulty: pure radium compounds are extraordinarily difficult to obtain. The radium I had prepared through fractional crystallisation was of exceedingly high purity, but one must account for any impurities or moisture. We employed multiple methods to assess purity: elemental analysis, spectroscopy, density measurements.
The calculation itself was straightforward once these two quantities were firmly established. But the work – the preparation, the repeated weighings, the electrical measurements made over months, the accounting for temperature changes, for atmospheric humidity, for instrumental drift – this was where precision lived. A half-life determination is only as good as the poorest measurement that enters it.
What was crucial was not novelty of method – these techniques existed – but rather the extreme care in execution. One might say that radiochemistry is not primarily about discovering new techniques. It is about executing known techniques with such discipline and repetition that the noise falls away and truth emerges.
This relates to something I’ve read about your chlorine isotope work. You challenged Irène Curie’s findings regarding whether chlorine’s isotopic composition varied by geological source. How did you approach that dispute?
This was a serious matter indeed. By the early 1920s, Francis Aston’s mass spectrograph had revealed that chlorine existed as two distinct isotopes: chlorine-35 and chlorine-37. The weighted average of their masses is approximately 35.45.
The question seemed simple but was profoundly important: does the ratio of these two isotopes vary depending on where the chlorine is extracted? If isotopic ratios were variable, then the entire foundation of chemistry – the periodic table itself – would be threatened. Atomic weights would no longer be constants. Chemistry would lose its quantitative basis.
Irène Curie, working in Paris, had found evidence suggesting that ratios did vary with source. This was alarming. If true, it meant that chemistry could not rely on constant atomic weights for common elements. The periodic system, which Mendeleev had built on the assumption of fixed atomic properties, would crumble.
I undertook a careful investigation using chlorine samples from diverse origins – deposits from Alsace, samples from salt mines, material from various geological formations. I employed gravimetric methods to determine composition with high precision. My measurements showed something quite different: the isotopic ratios remained constant. The chlorine-35 to chlorine-37 ratio was essentially identical regardless of source.
Now, how to account for Irène’s contrary findings? I concluded that contamination had occurred in her samples. This was not an accusation of carelessness – it was a technical assessment. Chlorine is volatile; contamination through atmospheric exposure or through interaction with apparatus is quite possible. My samples were handled with particular attention to this risk.
That must have been a delicate matter, contradicting the work of Irène Curie.
It was. But science is not improved by deference. If her measurements were compromised, saying so kindly does not alter the truth. My work preserved the concept of stable atomic weights for non-radioactive elements. This was not a small thing. I published my findings carefully, with complete documentation of method. The evidence accumulated. Slowly, the scientific community accepted my conclusions.
What I noticed, though, is that my contradicting Irène’s work was received somewhat coldly by certain French colleagues who held her in great reverence. Had a man contradicted her findings, I suspect the reception would have been different – more collegial, perhaps even celebratory as a matter of scientific progress. But a woman questioning another woman’s results seemed to touch a nerve. I was accused of being competitive rather than careful. This was unfair, but I have learned not to expect perfect fairness in how women’s work is interpreted.
Now I want to ask about your collaboration with Theodore Richards, the American Nobel laureate, on lead isotope work. You provided the radiogenic lead samples from Norwegian uraninite. What was your role in that research?
Ah, this is another instance where my contribution has been absorbed into his larger reputation. Richards was investigating whether lead derived from radioactive decay – radiogenic lead – had different atomic properties from ordinary lead. This would constitute direct chemical evidence for isotopes.
What was required were absolutely pure samples of uranium-derived lead. These would come from uranium ores – specifically, Norwegian uraninite – where the uranium had been decaying for geological timescales, producing lead-206 as a decay product. The challenge was extracting this lead in a state of complete purity, without contamination from ordinary lead.
I undertook this work. I possessed knowledge of Norwegian mineralogy – I was Norwegian, after all – and access to superior ore samples. More importantly, I possessed the technical skill in fractional crystallisation and gravimetric separation that could yield the necessary purity. The separation of radiogenic lead from other lead compounds in an ore matrix is extraordinarily demanding. It requires repeated recrystallisation, precise pH control, and monitoring for contamination.
I provided Richards with samples of such purity that his atomic weight determinations were definitive. He demonstrated that lead-206 – the product of uranium decay – had an atomic weight of approximately 206.04, whereas common lead (derived from other sources) had an atomic weight of approximately 207.2. This mass difference was unmistakable proof of isotopes.
Yet when his work is cited, you’re often mentioned only in passing, if at all.
Yes. This is the Matilda Effect, I believe historians now call it – crediting male colleagues with contributions that emerged from women’s experimental labour. My samples made his conclusion possible. Without them, he had only theory. With them, he had fact. Yet the fact is attributed to him; the experimental labour that produced the fact is footnoted, if at all.
I do not harbour resentment about this. I undertook the work because it was important, and because I was capable of it, and because the scientific question was genuinely interesting. But I should be clear: this pattern – where women’s meticulous experimental work is absorbed into male colleagues’ reputations – is not accidental. It is systematic. And it persists.
Let’s turn to your institutional position in Norway and the 1929 professorship controversy. You became the country’s second female professor, yet your predecessor and his allies actively opposed your appointment. Can you describe what that was like?
This is perhaps the most painful episode of my career, because it revealed that exceptional achievement – by the standards any man would face – was still insufficient.
I had been teaching at the University of Oslo since 1912, following my return from Curie’s laboratory. I had established the first courses in radiochemistry in Norway. I had published original research. I had trained students. I had gained international recognition – honorary doctorates from Smith College in 1914, the Sorbonne, other institutions. I had demonstrated beyond question that I was qualified.
Yet when the position of professor of inorganic chemistry became available in 1929, my appointment sparked extraordinary resistance. An expert committee recommended me. They examined my credentials, my publications, my teaching record, and they recommended my appointment. But my predecessor and his circle worked against it. They spread the view that I was “diligent but outdated” – that my research, whilst competent, lacked originality and innovation.
This assessment was simply untrue. My work on radium’s half-life, my investigations of isotopic composition, my contributions to atomic weight determination – these were not derivative work. They were original investigations that had advanced the field. But the narrative they constructed – a narrative that apparently still persists in some Norwegian chemical circles – was that I was a careful technician rather than a creative scientist. A distinction was made between doing experiments competently and doing science genuinely.
How did you respond to that?
I became a professor anyway. The appointment went through despite the opposition. And then I did what I had always done: I worked. I established a radiochemistry laboratory. I continued my research. I trained the next generation of Norwegian scientists. I refused to give my detractors the satisfaction of bitterness or self-doubt.
But I will tell you what I learned: that even exceptional achievement is not sufficient protection against prejudice. A man in my position would have been celebrated. I was merely tolerated. This is not a secret – everyone in the chemistry department knew it. But what could I do? Resign in protest? That would have served only to vindicate their claim that I lacked the temperament for serious science.
So I endured. And I worked. This is what women have often been required to do: to endure the injustice and to work despite it, as though the work itself would eventually change hearts and minds. Sometimes it does. Sometimes it does not.
I want to ask you about a more dramatic moment – the German occupation of Norway during the Second World War. There is a compelling account of a 1943 Gestapo raid on your laboratory, where you and your female colleagues managed to smuggle radioactive minerals out whilst male scientists were arrested. Can you tell me what happened?
Yes. This was perhaps the only moment in my scientific career when my work became explicitly political – when being a scientist and being a human being asking questions about justice became exactly the same thing.
Norway was invaded in April 1940. Within weeks, the Nazis had conquered militarily and established what they wished to be a cooperative state. But there was resistance. Quiet at first, then increasingly organised. I became involved in these networks. I was able to do so partly because I was a woman and an older woman at that. The occupiers seemed not to regard me as a genuine threat.
My laboratory became a place where resistance work could happen. Scientists and intellectuals who were targets – Jewish colleagues, political opponents of the regime – could shelter there. I had equipment, I had legitimate reason to be working, I had access to spaces the occupiers had not fully surveilled. This seemed to me not a political choice but a moral one.
In 1943, the Gestapo came. They had become aware of underground activity and conducted raids across the city. They entered my laboratory with typical brutality. What is interesting – what was, in fact, darkly useful – is that they viewed women scientists as essentially harmless. The male colleagues in the laboratory were arrested immediately. The female scientists – myself and others – were questioned but not arrested.
We were questioned about radioactive materials. They wanted to know what we were working on, whether any of it could be of military value. We told them truthfully that we were conducting basic research in radiochemistry. What they did not recognise was that we were also quietly, whilst they were distracted, removing certain mineral samples – radioactive materials – from the laboratory, hiding them where they would not be found.
Why was this important? What was the strategic value of the minerals?
This is the thing the occupation authorities did not grasp: radioactive materials were becoming strategically important because of atomic research. The Germans were pursuing nuclear weapons development. Radioactive minerals – uranium ore, radium compounds – were valuable to them. We understood, without being told explicitly, that our samples must be preserved away from Nazi control. It was not dramatic espionage. It was simply preventing the theft of scientific resources that we believed should not be in Nazi hands.
When the Gestapo left with the male scientists, we removed the materials. Simple as that. The men were held, questioned, eventually released or transferred. I was not arrested. I was, in the eyes of the occupiers, simply a rather elderly woman conducting routine scientific work.
What was so astonishing to me then, and remains with me, is how the prejudices that had limited my career became, in that moment, tactically useful. The assumption that women were harmless gave us a freedom of action that men did not possess. We used that freedom to do what we believed was right. It was ironic and unsettling and, in the end, necessary.
After the war, you worked with UNESCO on global literacy initiatives, but then you resigned in 1952 when Franco’s Spain was admitted as a member. That’s a remarkable act of principle.
Yes. I resigned. I was not alone in my objection, but I was one of the few willing to resign over it rather than simply to protest quietly.
Franco’s regime had committed atrocities. The Spanish Civil War had ended with Republican forces defeated and fascism triumphant. Tens of thousands had been killed or had disappeared. The regime was maintained through brutality and fear. And UNESCO, an organisation founded on principles of human dignity and intellectual freedom, admitted Spain as a member. Admitted it as though the regime’s crimes were not relevant to the decision.
I could not remain associated with an organisation that made such a choice. My wartime experience – sheltering people from occupation, witnessing the contempt for human life that authoritarianism produces – had shown me clearly that silence in the face of injustice is itself a choice. And I had chosen, throughout my life, not to be silent.
So I resigned. It was a small gesture in the larger scheme of things. But it was my gesture. One must use whatever authority one possesses to resist wrongdoing. I had some authority – a respected scientific figure, a former UNESCO official. I used it.
Did you feel this damaged your reputation in scientific circles?
My reputation was already quite secure by 1952. I was seventy-three years old. What could they do to me? They could not take away my professorship – I had earned it. They could not erase my publications. They could diminish my influence in certain circles, and I suspect some did. But I had never been seeking the approval of people whose morality I did not respect.
This is something I would say to young scientists, particularly women: do not spend your career trying to earn the approval of people who do not deserve your effort. Earn the approval of your own conscience. Do your work with integrity. Speak the truth when you see injustice. And if there are consequences, bear them with dignity.
Speaking of advice to young scientists – particularly women and others marginalised in science – what would you say to them looking at your career across time?
I would say several things. First: precision is power. Learn to do things so carefully, so meticulously, that no one can argue with your results. This is not solely a matter of technique – it is a form of authority that cannot be dismissed as emotional or subjective. When you present numbers obtained with perfect care, you are presenting fact. Your gender, your nationality, your background – these become less relevant when the evidence is undeniable.
But – and this is crucial – precision alone is not sufficient. One must also build networks. I spent enormous energy on the International Federation of University Women, establishing scholarship funds, creating pathways for women to study abroad. This was not separate from my science. It was strategic feminist infrastructure. If you are isolated, you are vulnerable. If you build connections with other women scientists, if you create systems of support and funding and mentorship, you become less easy to dismiss or marginalise.
Third: do not accept the premise that your success means the system is just. When I became a professor, colleagues told me this proved that women could succeed if they were sufficiently exceptional. But I was the second woman ever appointed to such a position in Norway. Exceptional individuals gaining access does not constitute systemic change. Do not let your own achievement blind you to the structures that still exclude others.
And finally – and perhaps most importantly – do not conflate patience with passivity. I endured much that was unjust, and I did so partly because that was the only strategy available to me. But I also resisted. I built alternative institutions. I refused to pretend that unjust treatment was acceptable. I resigned when principles required it. There is a difference between accepting what you cannot immediately change and accepting that things should remain as they are.
You’ve spoken about the need for women scientists to support each other. Did you find that Marie Curie extended such support to you?
Madame Curie was not primarily a mentor in the way we might understand mentorship today. She was a brilliant scientist conducting demanding research. She employed me as an assistant because I could do the work that was required. She was not unkind – she was professional and serious and focused on science. But our relationship was not intimate or particularly nurturing.
What she did offer, simply by being what she was, was an example of what was possible. She had won a Nobel Prize. She had established a major laboratory. She had published extensively. She had done this as a woman, and whilst it had cost her enormously – personally and professionally – it had been done. This example mattered. It meant that my own ambitions were not fantastic.
But I must be honest: Madame Curie did not systematically work to help other women in science. She was focused on her own research and, in those years I knew her, on coping with personal tragedy – her husband’s death, the attack on her reputation. She was occupied with survival. I do not fault her for this. But I recognised that if I waited for senior women scientists to create space for those of us coming after them, I would wait a long time.
So I created that space myself, through IFUW, through my teaching, through deliberately hiring women in my laboratory and supporting their research. This was conscious work. I saw it as a responsibility that came with my position.
Let me ask about a moment of failure or misjudgement. Is there something from your scientific career that, looking back, you wish you had approached differently?
Yes. There is something.
I was quite firm in my disagreements with Irène Curie regarding the isotopic composition of chlorine. I believed her results were contaminated. I published papers arguing this. I was, I believe, correct in my conclusions – the scientific record supported my interpretation. But I was also dismissive of her work in ways that were not entirely necessary.
She was a younger woman entering a field where her mother had been pioneering. She faced pressures I did not face – the pressure of following an extraordinary predecessor, of having to prove herself not merely as a scientist but as someone distinct from her mother’s shadow. I understood this burden intellectually, but I did not sufficiently appreciate it emotionally when I was critiquing her experimental technique.
I was competitive in a way that was perhaps harsher than required. I could have presented my findings – which were sound – without implying that her work was careless or inferior. I could have extended collegiality to a fellow woman scientist. Instead, I was focused on establishing the correctness of my own results. This is understandable, but I think it was not quite generous.
Looking back, I wish I had found a way to be both rigorous and kind. These are not mutually exclusive. One can present evidence firmly and still treat a colleague with warmth and recognition of their struggle.
That’s a remarkably honest reflection. Did you ever reconcile with her?
Not in any explicit way. We corresponded occasionally on scientific matters. We never addressed the disagreement directly. By the time she died – tragically early, you know, from radiation exposure – I had not had the opportunity to say to her that I respected her work and regretted any harshness. This is one of my genuine regrets. I had let competitiveness overshadow what might have been genuine scientific collegiality.
Your work has had tremendous impact on modern science, even if it’s not always attributed to you. Radium-226’s half-life as you determined it, isotope chemistry foundations, your contributions to atomic weight determination – all remain foundational. But what aspects of modern science would you like to see evolve differently?
I would like to see the scientific community become honest about the labour that undergirds discovery. We have a mythology of genius – the solitary individual who sees what others have missed, who has a revelation, who transforms a field. This is sometimes true. But more often, discovery emerges from meticulous experimental work done by many hands, often by people with less prestige, less visibility, less credit.
In my own work, I performed fractional crystallisations for five years. This was not glamorous. It did not require novel thinking. It required discipline, care, repetition. Yet this labour made possible the theoretical insights that Madame Curie and others developed. We celebrate the theory and forget the labour.
If I could change something about how science is practiced and understood, I would make visible the contributions of technicians, of laboratory assistants, of the people doing the meticulous experimental work. I would ensure they are credited in publications, that their expertise is recognised, that their career paths do not dead-end because they are classified as “support” rather than as creative scientists.
This would require, I think, changing how we define scientific contribution. We have been far too focused on novelty of theory and far too dismissive of precision in execution. Both matter. Both are creative work. A field advances when both are valued.
As we near the end of our time, I’m curious – what did you most love about your work? Beyond recognition, beyond institutional advancement, what kept you engaged in science?
The beauty of precision itself. There is something almost spiritual about bringing order to the physical world through careful measurement and observation. When you determine something to be true not because you believe it or because it fits a theory you like, but because you have measured it carefully, repeatedly, and the measurements converge on a single answer – there is an extraordinary satisfaction in that.
I also loved the community of it. Though I have spent much of my career feeling somewhat separate from my Norwegian colleagues, I was never separate from the international scientific community. I corresponded with Rutherford, with Boltwood, with Richards. I attended conferences where I heard the latest ideas directly from those who had thought them. That was a privilege – to be part of a community of people asking the same questions, speaking the same language of chemistry, united by curiosity about how the physical world actually works.
And I loved – perhaps this will sound sentimental – the sense that my work mattered. That the half-life I determined would be used by physicians treating cancer patients. That the atomic weights I had verified would be taught to students learning chemistry. That the systems I had built through IFUW would enable other women to do science when their own institutions refused them. This was meaningful. This was not merely passing time; this was contributing something that persisted.
Even now, knowing that my name appears less often than it should in the historical record, I know that my work persists. Those who know radiochemistry thoroughly know my contributions. Those who study the history of women in science are beginning to find me. My institutions – the laboratory in Oslo, the fellowship funds through IFUW – continue. This is enough. This is more than enough.
Final question: if you could speak directly to the next generation of scientists – to those working on problems we cannot yet imagine – what would you want them to know?
I would say this: care intensely about getting things right. In a world that will often ask you to compromise, to hurry, to accept what is convenient, to work within systems that are broken – care about getting things right. Do your work with such precision and integrity that no one can question it. This is your power.
I would also say: build communities of support. Do not imagine that you must succeed alone. Create systems of mentorship, funding, and mutual aid. If your institution will not support you, build your own institution. I did this. It was possible, even in my era, even with my constraints. It is more possible now.
And finally: remember that science is not separate from the world. The choices you make about where to work, whose work you support, whose exclusion you tolerate – these are moral choices. Science is pursued by human beings within human societies. It is not somehow exempt from ethics. So pursue your science with integrity and with consciousness of its place in the world.
The half-life of radium-226 is approximately 1,600 years. My work will be used, by scientists yet unborn, to solve problems I cannot imagine. This gives me tremendous peace. Your work will do the same. Make it worthy of that future. Make it rigorous. Make it just. Make it true.
Letters and emails
Following our conversation with Ellen Gleditsch, we received an overwhelming response from readers, researchers, and scientists around the world – each eager to extend the dialogue, to probe deeper into the dimensions of her work that resonated most urgently with their own lives and pursuits. From these letters and emails, we’ve selected five from our growing community, representing diverse perspectives across continents and disciplines. Each writer brings their own curiosity, their own expertise, their own questions about what it means to work with integrity in fields where that integrity is constantly tested. These are not the questions of formal scholarship, but rather the genuine inquiries of thoughtful people who recognise in Ellen Gleditsch’s life something that speaks to their own struggles, their own hopes, their own sense of what science might become. What follows is a collection of voices in dialogue with hers – a conversation that extends beyond the laboratory and into the deeper territory of what it costs to create knowledge whilst remaining true to one’s conscience.
Samira Ouattara, 34 | Science Communication & Public Engagement | Dakar, Senegal
You spent five years doing fractional crystallisations of radium in Curie’s laboratory – work so repetitive that most people would find it maddening. But you describe it with a kind of reverence. I’m curious: did you ever feel the pull to move into theoretical work, or was there something about the doing of chemistry – the hands-on manipulation, the physical engagement with materials – that kept you grounded in experimental work even when you had the credentials to move away from it?
This is a question that touches something quite fundamental about how I understand myself as a scientist, and I am grateful for it.
Yes, I felt the pull toward theoretical work – of course I did. When you are surrounded by people like Ernest Rutherford, Niels Bohr, and the constellation of physicists who were revolutionising our understanding of atomic structure in the 1910s and 1920s, it is impossible not to feel the allure of abstraction. Theory seemed to possess a certain glamour, a kind of intellectual prestige that experimental chemistry lacked. The theorists were the ones whose names appeared prominently in newspapers, whose ideas sparked debate in philosophical circles. They were the architects; we experimentalists were merely the builders.
But I realised quite early – perhaps during those long hours at the crystallisation bench in Paris – that this hierarchy was false. Or rather, it was constructed to privilege certain kinds of work over others, and that construction served particular interests. Theory without experimental verification is speculation. Beautiful speculation, perhaps, but not science in the full sense. And experimental work, when done with sufficient care and insight, is not merely verification – it is discovery in its own right.
What kept me grounded in experimental chemistry was partly temperament and partly conviction. The temperament: I have always found profound satisfaction in working with my hands, in the direct engagement with materials. There is something deeply honest about it. When you crystallise a salt, when you weigh a sample, when you measure radioactive decay – you are in conversation with physical reality itself. The material does not lie. It does not flatter you. It does not care about your theories or your reputation. It simply is, and your task is to understand it accurately.
I found this relationship clarifying. In a world where so much of what was said about women, about our capacities and our proper place, was fabrication and prejudice, the laboratory offered something wonderfully indifferent to such nonsense. Radium decays at a particular rate regardless of who is measuring it. Chlorine’s isotopic composition does not vary based on the gender of the chemist analysing it. This was liberating.
The conviction came from recognising that precision itself is a form of intellectual creativity. When I was determining radium’s half-life at Yale, I was not merely following established procedures. I was making hundreds of small decisions about technique, about how to minimise error, about which measurements to trust and which to repeat. This required judgement, insight, and a kind of intuitive understanding of where uncertainty enters experimental work. That is creative labour. It is not less creative than proposing a new model of atomic structure – it is differently creative.
Furthermore, I came to believe that experimental chemistry was undervalued precisely because it was often performed by women and by those with less institutional power. The pattern was unmistakable: work that required patience, meticulous care, and physical endurance was classified as “routine” or “technical” rather than “scientific” in the highest sense. Yet remove that work, and the entire edifice of theoretical physics collapses. Marie Curie’s theoretical insights about radioactivity depended utterly on having pure samples of radium and polonium. Those samples existed because people like me – and Gustave Bémont, and others – spent years purifying them.
So I made a choice, quite consciously, to remain an experimentalist. I would not seek to escape into theory as though experimental work were beneath me. Instead, I would demonstrate that experimental chemistry, pursued with rigour and intelligence, was itself a complete scientific vocation.
There was also something else, something harder to articulate. I found beauty in the repetition. The fractional crystallisations were, yes, tedious – five years of crystallizing, filtering, recrystallising. But within that repetition, one develops an almost meditative attention. You learn to notice tiny variations in crystal formation, slight changes in colour or texture that indicate impurity or contamination. You develop what I can only call a physical intuition – a sense of when the procedure is proceeding correctly and when something is subtly wrong. This cannot be taught from textbooks. It emerges from sustained, attentive practice.
I think of it rather like a musician practicing scales. The scales themselves are not music, but the musician who has practiced them ten thousand times possesses a fluency, a physical understanding of the instrument, that enables artistry. My years of repetitive crystallisation gave me that fluency with radioactive materials. When I later worked on atomic weight determinations, on isotope chemistry, I could trust my technique absolutely because I had performed it so many times that error was immediately apparent.
So no, I did not wish to escape experimental work. I wished to see it honoured properly. I wished for a world where the experimentalist’s contribution was recognised as intellectually substantial, where precision was understood as a form of knowledge-making, where the person who spends five years purifying radium is credited alongside the person who uses that radium to develop theoretical insights.
This is, I suppose, a longer answer than you anticipated. But your question deserved it. You asked whether there was something about the doing that kept me grounded. Yes. The doing was not separate from the thinking – it was the thinking, embodied in careful hands and disciplined attention. That was enough for me. It was more than enough.
Cole Armstrong, 41 | Nuclear Physics Researcher | Vancouver, Canada
Your measurement of radium-226’s half-life at approximately 1,600 years remained the standard for half a century. By modern standards, with our mass spectrometry and nuclear counting techniques, we can determine half-lives with extraordinary precision. But I’ve always wondered: looking at your methods now, what do you think was the limiting factor – was it instrumental sensitivity, the purity of your samples, or something about the fundamental physics of measurement itself? And are there aspects of your approach that modern radiochemists have, perhaps inadvertently, abandoned?
ou have asked precisely the right question, and I appreciate that it comes from someone who understands the technical dimensions of the work. Let me address each part carefully.
The limiting factor in our half-life determination was unquestionably instrumental sensitivity, though sample purity ran a very close second. Allow me to explain why both mattered so profoundly.
When Bertram Boltwood and I worked on radium’s half-life at Yale in 1913 and 1914, we were measuring extraordinarily small quantities of radioactive decay. The fundamental measurement required two values: the mass of radium present and the activity – the rate at which it was emitting alpha particles. The mass we could determine gravimetrically with considerable precision using analytical balances. These instruments were excellent – capable of detecting differences of a few micrograms when properly calibrated and used in controlled conditions. That was not the problem.
The activity measurement, however, presented formidable challenges. We used an electrometer to detect the ionisation produced by alpha particles in air. When an alpha particle passes through air, it ionises the gas molecules, creating charged particles that can be detected as a tiny electrical current. This current is proportional to the number of alpha particles being emitted – which is to say, proportional to the activity of the radium sample.
But here is where instrumental sensitivity became crucial. The currents we were measuring were extraordinarily small – on the order of 10⁻¹⁴ amperes or smaller. The electrometers available to us in that era were sensitive, yes, but they were also temperamental. They drifted. They responded to temperature fluctuations, to humidity changes, to vibrations in the building. We had to make measurements over extended periods – hours, sometimes days – to obtain reliable averages. And even then, the uncertainty in each individual measurement was considerable.
Modern nuclear counting equipment – scintillation counters, semiconductor detectors, your mass spectrometers – these instruments can count individual decay events with extraordinary efficiency and minimal background noise. You can accumulate statistically significant data in minutes or hours rather than weeks. The precision you achieve is orders of magnitude better than what we could manage. If I could have had access to such instruments, our uncertainty would have been reduced dramatically – perhaps by a factor of ten or more.
But sample purity – that was equally limiting, and in some ways more insidious. Radium-226 decays through a series of daughter products: radon-222, polonium-218, lead-214, and so forth down the decay chain. If your radium sample is not in secular equilibrium – that is, if the decay products have not reached a steady state where they are being produced as rapidly as they decay – your activity measurement will be incorrect. Freshly purified radium takes weeks to reach equilibrium with its daughters. If you measure too soon, you underestimate the activity. If your sample contains other radioactive contaminants – traces of uranium, thorium, or their decay products – you overestimate it.
I spent enormous effort ensuring sample purity. The radium I prepared had been through dozens of fractional crystallisations. I verified purity through spectroscopic analysis, looking for the characteristic emission lines of radium and checking for contaminating elements. I measured density to confirm that the crystalline material matched the expected properties of pure radium bromide or radium chloride. Even so, achieving absolute purity was impossible. There were always trace impurities at some level. The question became: were they sufficient to introduce significant error into the half-life determination?
I believe – and I have thought about this carefully over the years – that our measurement was as good as it was primarily because of sample purity rather than despite instrumental limitations. Had we used impure samples with perfect instruments, we would have obtained a precise but inaccurate result. The precision would have been false. But with very pure samples and moderately sensitive instruments, we obtained a result that was both reasonably precise and, more importantly, very close to the true value.
Now, to your second question: have modern radiochemists abandoned aspects of our approach? I think the answer is yes, though not intentionally and perhaps not detrimentally.
What we possessed – what we were forced to possess because our instruments were limited – was an intimate physical understanding of the samples themselves. I could look at a crystal of radium salt and judge its purity based on colour, on how it formed, on subtle characteristics of the material. I understood, at a tactile level, what highly purified radium behaved like. This knowledge was gained through hundreds of hours of direct work with the substance.
Modern instrumentation allows you to analyse samples without this kind of prolonged physical engagement. You can determine composition, structure, purity – all through instrumental analysis. This is enormously powerful. But I wonder whether something is lost when the scientist’s relationship with the material becomes primarily mediated through electronic readouts rather than through direct manipulation.
There is also the question of error analysis. Because our measurements were so difficult and so prone to uncertainty, we developed a rigorous discipline around identifying and quantifying sources of error. Every measurement came with a careful accounting of what might have gone wrong – instrumental drift, temperature effects, sample contamination, geometric factors in detector placement. We could not simply trust the instrument; we had to understand its limitations intimately.
I have observed, in reading some modern radiochemistry literature, that this discipline is occasionally less evident. The instruments are so good that there is perhaps a temptation to trust them implicitly, to assume that the readout is truth rather than an approximation to truth. This would be a mistake. No instrument, no matter how sophisticated, is free from sources of error. The scientist must remain sceptical, must interrogate the measurement, must ask what assumptions underlie the result.
Finally – and this may sound rather philosophical for a technical discussion – there is the matter of patience. Our methods required extraordinary patience. Measurements took weeks or months. Purifications took years. One could not rush the work. This enforced patience created space for careful thought, for noticing unexpected patterns, for developing intuition about the material.
Modern methods are faster, and this is generally advantageous. But I wonder whether there are insights that emerge only when one is forced to wait, to observe over long timescales, to notice subtle changes that rapid measurements might miss. Perhaps not. Perhaps I am simply romanticising the constraints under which I worked. But I do think there is value in slow, patient observation that should not be entirely supplanted by rapid instrumental analysis.
In sum: our limiting factors were instrumental sensitivity and sample purity, in roughly equal measure. Modern radiochemistry has solved the instrumental problem magnificently. But the importance of sample purity, of intimate material knowledge, of rigorous error analysis, and of patient observation – these remain as relevant now as they were in my time. If they have been abandoned, they should be recovered. If they have been preserved, they should be honoured as essential to good science.
Laksmi Dewi, 38 | Geochemistry & Environmental Monitoring | Jakarta, Indonesia
Your work proving that chlorine’s isotopic composition doesn’t vary by geological source resolved a crisis in early 20th-century chemistry. Today, we use isotope ratios extensively for environmental forensics – tracing pollution sources, understanding water cycles, reconstructing paleoclimate. Do you think you anticipated, even dimly, that isotope chemistry would become such a powerful tool for understanding planetary systems? And if you had known then how central isotope tracing would become to environmental science, would that have changed how you approached your investigations?
This is a remarkable question, and it requires me to be honest about the limits of my own foresight – which is to say, the limits were quite severe. But let me try to answer both parts with the care your question deserves.
Did I anticipate, even dimly, that isotope chemistry would become so central to understanding planetary systems? The truthful answer is: I had glimpses, but I did not see clearly. I could not have.
In the 1920s, when I was conducting my chlorine work, we were still discovering fundamental facts about isotopes themselves. Francis Aston’s mass spectrograph had revealed that elements existed as multiple isotopic forms – this was remarkable, almost shocking. The existence of isotopes was still quite new. We were in the phase of cataloguing, of measuring, of understanding the basic properties of these phenomena. We were not yet in a position to ask about their applications to large-scale planetary processes.
What I did understand was that isotopes represented a new kind of chemical fingerprint. Different isotopes of the same element have essentially identical chemical properties – they behave the same way in chemical reactions, they combine with other elements in the same proportions. Yet they differ in mass. This means that if you could measure isotopic ratios precisely, you could potentially identify the source or history of a chemical substance without altering its essential nature. This idea fascinated me intellectually. It suggested that chemistry possessed hidden dimensions – that two samples of chlorine might look identical to ordinary analysis, yet the ratio of their isotopes could tell you something about their origin.
But the applications I imagined were limited to laboratory chemistry and perhaps to geological investigations of rocks and minerals. I did not conceive of using isotope ratios to understand global water cycles or to trace pollution across continents. Partly this was limited imagination on my part. Partly it was that the instrumental techniques required for such investigations did not exist. How would one measure isotopic ratios with sufficient precision across thousands of samples? It seemed impractical. The equipment to do such work at scale was not available.
What I did anticipate, I think quite clearly, was that proving the constancy of isotopic ratios was crucial for preserving the periodic table and quantitative chemistry itself. If isotopic composition had varied by source, it would have been catastrophic for chemistry. Atomic weights would have become meaningless. All quantitative chemical work would have been undermined. So when I set out to determine whether chlorine’s isotopic ratio was constant, I understood the stakes. This was not merely an academic question. It was foundational.
If I had known then – had somehow possessed a vision of 2025, with your isotope ratio mass spectrometers and your global databases of environmental samples and your ability to trace water vapour through the atmosphere using oxygen isotopes – would that have changed my approach?
Honestly, I do not think it would have changed the fundamental questions I asked. The question “does isotopic composition vary by source?” would have been equally urgent, whether the application was purely academic or whether it was destined to enable environmental forensics decades in the future. But I confess that knowing the magnitude of future applications might have affected my confidence in the importance of the work. I pursued it with conviction because I understood its importance to chemistry’s foundations. But if I had known it would eventually enable scientists to track pollutants across oceans and continents, to reconstruct ancient climates, to understand the water cycle in unprecedented detail – I might have pursued it with even greater urgency.
What interests me now, looking at your description of isotope work in environmental science, is the question of precision and scale. When I was determining isotopic ratios for chlorine, I was working with perhaps a dozen samples, each requiring months of careful preparation and analysis. The measurements were extraordinarily labour-intensive. The precision was good – perhaps one part in a thousand – but there were significant uncertainties.
You are apparently measuring thousands or millions of samples, with instruments that provide precision perhaps a hundred times better than what we could achieve. This is not merely an incremental improvement; it is a transformation. It makes possible investigations that were literally inconceivable in my era because the labour required would have been prohibitive.
Yet I wonder about something. With such abundance of data, with such powerful instrumental capability, is there a risk of losing the intimate relationship with the material that careful, labour-intensive work forces upon you? When one spends weeks preparing a single chlorine sample, learning its properties, testing it, refining the purification – one understands that sample in a way that rapid instrumental analysis might not convey. I do not know whether this matters for your environmental work. But I suspect that understanding why an isotope ratio is what it is – understanding the chemical and physical processes that created that ratio – requires more than instrumental precision. It requires thought, intuition, and sometimes the kind of slow knowledge that comes from direct engagement with materials.
I would ask: in your environmental isotope work, do you find that some of your most important insights come from careful study of individual samples, from asking why a particular sample behaves differently, from pursuing anomalies? Or do your insights emerge primarily from statistical analysis of large datasets? I suspect the answer is “both” – that you need the statistical overview that massive data provides, but also the detailed understanding that comes from attention to particularity.
If that is true, then my work – proving that isotopic ratios were constant and reliable across different sources – created the foundation for what you do now. The constancy I demonstrated meant that deviations from that constancy are meaningful. When you find a pollution source or trace a water mass through the ocean, you are relying on the fact that isotopic composition, in normal geological circumstances, remains constant. Anomalies matter precisely because of the baseline.
So perhaps my answer is this: I did not anticipate the full scope of applications you are now pursuing. I could not have. The technology did not exist; the questions had not been formulated. But I understood that I was establishing something foundational – that isotopic ratios were reliable, constant, meaningful. I pursued that understanding with all the rigour I could muster. And it seems to have enabled discoveries I could not have imagined.
Whether I would have felt greater urgency had I possessed foresight – I think yes. Not because the answer would have changed, but because knowing the magnitude of future benefit might have crystallised the importance of patience, of precision, of refusing to accept anything less than accuracy. The work was worth doing for its own sake, for the integrity of chemistry. But knowing it would eventually enable scientists like yourself to understand and protect planetary systems? That would have been a tremendous validation of why meticulous science matters.
Javier Montenegro, 47 | Philosophy of Science & Ethics | Buenos Aires, Argentina
I’m humbled by your 1952 resignation from UNESCO over Franco’s Spain. It cost you something – perhaps not dramatically, given your age and security, but it cost something. And yet so many brilliant scientists throughout history have made the calculation that not speaking out protects their ability to do science. I want to ask: do you believe there was a moment earlier in your career – perhaps when you were younger and more vulnerable – when you couldn’t afford to take such stands? And if so, does that create a kind of moral debt for those of us who gain security and recognition later?
You have asked a question that goes directly to the heart of something I have thought about a great deal, particularly in my later years. It is uncomfortable territory, but you have asked it with sufficient care that I feel obliged to answer honestly.
Yes. There were absolutely moments earlier in my career when I could not afford to take principled stands of that magnitude. Many such moments. And yes, I believe this creates what you aptly call a moral debt – though I would frame it somewhat differently. Let me explain.
When I was a young woman in my twenties and thirties, working without secure position or income, my capacity for public protest was severely constrained. I was dependent on the goodwill of institutions that did not particularly want me. When I worked in Marie Curie’s laboratory from 1907 to 1912, I was classified as an assistant, paid nothing, my laboratory fees waived because the work I did was so technically demanding that few others could do it. I was tolerated rather than welcomed. Had I made trouble – had I criticised the laboratory’s practices, or objected to my treatment, or made political statements that embarrassed the institution – I would simply have been dismissed. And where would I have gone? Back to Norway, where I had no university position, no laboratory, no means of continuing scientific work.
This reality shaped my behaviour profoundly. I was quiet. I was diligent. I did not complain. I focused on the work itself and avoided anything that might be construed as difficult or troublesome. When I encountered injustice – and I encountered it frequently – I absorbed it rather than confronting it. This was not cowardice exactly, though it was not courage either. It was calculation. I calculated that my ability to do science at all depended on not antagonising those who held power over my access to laboratories, equipment, funding, publication.
When I went to Yale in 1913, despite having been rejected initially, I was extraordinarily careful in how I conducted myself. I did not demand recognition. I did not insist on being treated as Boltwood’s equal, though in terms of technical skill I certainly was. I accepted a subordinate status because asserting equality would have risked the entire arrangement. Boltwood was reluctant to have me there; I knew this. So I made myself useful, indispensable, quiet. Only after the measurements began accumulating, only after it became clear that my work was producing results of genuine importance, did I gain enough standing to be treated as a collaborator rather than an interloper.
This pattern continued throughout my early and middle career. Even when I returned to Norway and began teaching at the University of Oslo, I was in a precarious position. I had no tenure, no permanent appointment, no guarantee of continued employment. When I applied for the professorship in 1929, the opposition I faced was fierce. Had I been known as a troublemaker, as someone who made political statements or challenged institutional practices, I suspect the opposition would have been insurmountable. As it was, I barely succeeded.
So yes – there were many moments when I could not afford to take the kind of stand I took in 1952. The difference by 1952 was that I had achieved a secure position. I was seventy-three years old. I had been a full professor for more than twenty years. I had international recognition, honorary doctorates, a body of published work that could not be erased. Most importantly, I had retired in 1946. My livelihood no longer depended on institutional approval. I was financially secure through my pension. This security – earned over decades of careful, quiet work – gave me the freedom to resign on principle.
Now, does this create a moral debt? You suggest it does, and I think you are right, though the nature of that debt requires careful consideration.
I do not believe I was morally obligated to sacrifice my entire scientific career for the sake of protest in my youth. Had I done so, I would have accomplished nothing. I would have been dismissed from Curie’s laboratory, would never have determined radium’s half-life, would never have contributed to isotope chemistry, would never have become a professor, would never have trained the next generation of Norwegian scientists. My silence, in those years, enabled work that mattered. This is not purely self-justification – it is a realistic assessment. Sometimes one must endure injustice in order to reach a position from which one can effectively challenge it.
But – and this is crucial – having reached that position, having gained security through years of careful navigation, I then became morally obligated to use that security for something beyond my own comfort. This is the debt you identify. Those of us who achieve positions of relative safety and authority have a responsibility to those who are still vulnerable, still precarious, still unable to speak without risking everything.
When I resigned from UNESCO in 1952, I was not risking my livelihood. I was risking only my comfort, my prestige within certain circles, my access to international organisations that I no longer needed. The cost to me was minimal. But the gesture mattered – or I believed it mattered – precisely because I had standing. A resignation from an elderly, respected scientist carried weight that a complaint from a young, untenured assistant would never have carried.
So the debt is this: if you have been silent when you were vulnerable, you are obligated to speak when you become secure. If you have benefited from keeping your head down, from not making trouble, from calculating that your work was more important than your protest – then when you finally reach a position of safety, you must repay that silence with courage.
I should say that this is uncomfortable to acknowledge because it reveals the extent to which I was complicit in systems I knew to be unjust. I did not challenge the institutions that marginalised me when I was young because doing so would have ended my career. But by not challenging them, I allowed them to continue marginalising others. My silence, however necessary it felt at the time, enabled the continuation of injustice.
This is perhaps the most difficult aspect of what you are asking: the recognition that survival within unjust systems requires compromises that perpetuate those systems. I was a beneficiary of my own compliance. I gained access to laboratories and positions by not being difficult, by accepting treatment that should not have been acceptable. And by doing so, I implicitly validated that treatment as something women should be willing to endure.
The debt, then, is not merely to speak out later. It is also to acknowledge honestly that one’s own success came partly through accommodation with injustice. And to work, in whatever time and capacity one has, to dismantle the structures that required such accommodation.
After I retired, I worked with UNESCO initially because I believed in international cooperation on education and literacy. These were causes that mattered deeply to me. When Spain was admitted in 1952, despite Franco’s regime being maintained through violence and repression, I could not remain associated with the organisation. This was not heroism – it was simply using the freedom I had finally earned.
But I will say this: I wish I had found ways to resist earlier. Not in ways that would have destroyed my career entirely – I do not think self-destruction serves justice – but in smaller ways. I could have been more vocal in supporting other women scientists. I could have used my position, once I had it, to create more protective space for younger scholars facing the same pressures I had faced. I did some of this through the International Federation of University Women, but I could have done more.
So to those of you who have gained security through careful navigation of unjust systems: yes, there is a debt. Use your security to protect those who are vulnerable. Speak when you have standing to speak. Resign when resignation matters. Create pathways for others that did not exist for you. And acknowledge, with humility, that your success came partly through compromises that others are still being forced to make. The debt is paid not through guilt, but through action – through using whatever authority you have accumulated to make the path easier for those who come after.
Roisin Gallagher, 29 | Science Historian & Gender Studies Scholar | Dublin, Ireland
I notice that in the interview you spoke quite candidly about your regret regarding how sharply you critiqued Irène Curie’s chlorine work. But I wonder – and this is perhaps uncomfortable to ask – whether some of that sharpness came partly from a need to assert your own originality and independence at a time when being associated with or compared to anyone else’s work (especially another woman’s) risked erasure. Did you ever feel trapped between needing to prove your work was distinctly yours whilst also needing support and recognition from within a scientific community that barely acknowledged women’s contributions?
You have put your finger on something that causes me considerable discomfort even now, and I am grateful for the precision of your question. Yes. The answer is yes, and it is more complicated and more painful than I have previously been willing to admit.
I was trapped exactly as you describe. But let me try to explain the mechanisms of that trap, because I think they reveal something important about how women scientists were – perhaps still are – positioned against one another.
When I published my findings contradicting Irène Curie’s chlorine results in the early 1920s, I was in a particularly vulnerable position professionally. I had returned to Norway after my work with Boltwood at Yale. I was teaching at the University of Oslo, but without permanent appointment. I was known internationally, yes, but my reputation was still forming. And there was a persistent narrative – one that my Norwegian colleagues seemed rather fond of – that I was a competent technician rather than an original scientific thinker. That I was good at executing other people’s ideas but not at generating my own.
This narrative was profoundly threatening. If it became established, if it solidified into received opinion, I would never advance. I would remain forever an assistant, a skilled pair of hands but not a mind worth taking seriously. So when I discovered that Irène’s results were inconsistent with my own measurements, I faced a choice.
I could have been gentle. I could have published my results and suggested, diplomatically, that perhaps both our findings were correct under different conditions, that further investigation was needed, that the discrepancy was interesting and merited collaborative attention. This would have been collegial. It would have preserved the possibility of working together to resolve the question.
But I was afraid – deeply afraid – that such diplomacy would be interpreted as weakness or uncertainty. I was afraid that male colleagues would see collaboration between two women scientists as confirmation that we needed each other’s help because neither of us was capable of independent work. I was afraid that my results would be dismissed as derivative if I presented them too tentatively.
So instead I was sharp. I stated clearly that Irène’s results were wrong. I attributed the error to contamination. I presented my own findings with confidence bordering on aggression. I made certain that no one could mistake my work for anything other than independent, rigorous, and definitive.
And it worked, in a sense. My results were accepted. The scientific community concluded that I was correct and that Irène’s measurements had indeed been compromised. My reputation as an original investigator was enhanced. The narrative that I was merely a technician became harder to sustain.
But the cost – and this is what I have come to understand only with considerable reflection – was that I contributed to a dynamic that isolated women scientists from one another. Rather than building solidarity, rather than creating a network of mutual support, I had competed. I had positioned my success as requiring Irène’s failure.
This was not entirely my fault. The structure of scientific recognition in that era made it almost inevitable. There was so little space for women in prestigious scientific positions that we were forced to compete for the few available places. It was rather like a game of musical chairs: if there is only one chair, and two women are standing, the game requires that one sit and one be excluded. Under such conditions, solidarity becomes difficult. One’s advancement seems to require someone else’s diminishment.
But here is what makes it particularly painful: Irène and I were both daughters, in different senses, of Marie Curie’s legacy. Irène literally, as her daughter. I figuratively, as someone who had trained in her laboratory and worked in radiochemistry. We should have been natural allies. We should have supported one another, collaborated, defended each other’s work against the dismissive attitudes we both faced from male colleagues. Instead, I critiqued her work harshly and publicly.
Was this partly strategic? Yes. Was it necessary for establishing my independence? Perhaps. But was it also shaped by a scarcity mentality – a belief that recognition for her would mean less recognition for me? I think it was. And that scarcity mentality was not something I invented. It was created by institutions that admitted women so grudgingly that each woman’s presence seemed to be at the expense of another’s.
There is another dimension to this that I have thought about considerably. When women scientists criticised each other’s work, it was interpreted very differently than when men did so. When Ernest Rutherford disagreed with Frederick Soddy about radioactive decay mechanisms, this was understood as vigorous scientific debate – as healthy, productive contestation that would lead to truth. When I disagreed with Irène, it was sometimes interpreted as personal animosity, as women being unable to work together, as evidence that women were too emotional for objective science.
This double standard meant that any disagreement between women scientists became fraught with additional meaning. It was not simply a technical dispute; it became a referendum on women’s capacity for collegiality and rationality. This made scientific disagreement between women far more costly than equivalent disagreements between men.
So I became more careful, more measured, more diplomatic in how I phrased technical criticisms – except when I felt my independence was threatened. And with Irène, I felt precisely that threat. She was Marie Curie’s daughter, working in the same field, in the same laboratory. The risk of being seen as secondary to the Curie legacy was acute. So I overcompensated. I was sharper than necessary to establish clear separation.
Looking back, I wish I had found a way to disagree with her results whilst simultaneously expressing respect for her work and solidarity with her position as a woman scientist facing many of the same barriers I faced. These need not have been mutually exclusive. I could have said: “Her measurements, whilst carefully conducted, appear to show contamination. My own results, obtained through the following methods, suggest different conclusions.” This would have been both rigorous and generous.
Instead, I allowed fear – fear of erasure, fear of being considered derivative, fear of losing the precarious standing I had gained – to shape how I engaged with another woman scientist’s work. And in doing so, I contributed to the very isolation that made women’s scientific work more difficult.
You asked whether I felt trapped between proving my work was distinctly mine and needing support from a scientific community that barely acknowledged women’s contributions. Yes, absolutely. And that trap had no good escape. If I emphasised my connections to other women scientists – if I presented my work as building on Marie Curie’s or collaborating with Irène’s – I risked being seen as dependent, as lacking originality. But if I emphasised my independence, if I distanced myself from other women’s work or criticised it sharply, I contributed to a narrative that women scientists could not work together effectively.
The trap was designed such that either choice reinforced structures of exclusion. Either I was too connected to other women and therefore not independently capable, or I was too critical of other women and therefore proof that women could not collaborate. There was no position from which I could both maintain my own standing and build solidarity with other women scientists without risking one or the other.
What I have learned – too late to help Irène, who died in 1956 – is that the trap itself must be named and refused. One refuses it by insisting that technical disagreement is compatible with solidarity, that women scientists can critique each other’s work rigorously whilst simultaneously supporting each other’s right to do that work. One refuses it by creating institutions – like the International Federation of University Women – that provide support networks independent of whether one agrees with particular research findings.
But I did not understand this clearly enough in the 1920s. I was operating within the constraints I perceived, trying to survive in a profession that did not particularly want me. And I made choices that, whilst understandable, were not as generous or as wise as they might have been.
So yes, I was trapped exactly as you describe. And I regret that I did not find a way to escape that trap that preserved both my scientific integrity and my solidarity with other women facing the same pressures. Perhaps such an escape was not possible in that era. But I wish I had tried harder to find it.
Reflection
Ellen Gleditsch died on June 5th, 1968, at the age of eighty-eight, in Oslo – the city where she had spent decades building a radiochemistry laboratory, training generations of Norwegian scientists, and proving, through sheer persistence, that exceptional achievement could force open doors that institutions preferred to keep closed. Nearly sixty years after her death, this fictional conversation has allowed us to explore not merely what she accomplished, but how she navigated a scientific landscape designed to exclude her, and what that navigation cost.
Throughout our dialogue, certain themes emerged with remarkable consistency: the undervaluation of meticulous experimental work compared to theoretical innovation; the trap that forced women scientists to choose between independence and solidarity; the moral calculations required to survive within unjust systems whilst preserving the capacity to challenge them later. Gleditsch’s reflections on her five years of fractional crystallisations in Marie Curie’s laboratory revealed not tedium but a kind of devotion – an understanding that precision itself constitutes intellectual creativity, that repetitive work performed with sufficient care becomes a form of knowledge that cannot be gained any other way.
Her account of arriving uninvited at Yale in 1913, after being rejected for a fellowship, captures something essential about the additional labour women scientists have always been required to perform: not merely doing excellent work, but doing it in circumstances specifically designed to prevent them from doing it at all. Bertram Boltwood’s initial resistance, documented in his correspondence with Ernest Rutherford, transformed into collaboration only when her measurements proved undeniable. This pattern – competence grudgingly acknowledged rather than eagerly welcomed – shaped her entire career.
The historical record offers fragments of Gleditsch’s voice through her published papers and occasional biographical accounts, but this imagined conversation has necessarily filled gaps with interpretation. We cannot know precisely how she felt about her complicated relationship with Irène Curie, though the scientific disagreement over chlorine isotopes is well documented. We cannot be certain of her inner calculations during the 1929 professorship controversy, though the opposition she faced is a matter of record. What this fictional interview has attempted is emotional archaeology – excavating the probable feelings, fears, and strategic decisions that accompanied her public achievements.
Where her perspective here may differ from some historical accounts is in the frank acknowledgment of compromise and complicity. Traditional narratives of women pioneers sometimes emphasise triumphant perseverance whilst obscuring the accommodations required for survival. Gleditsch’s admission that she remained quiet when vulnerable, that she competed with other women scientists partly because institutional scarcity demanded it, that her success came through navigation of injustice rather than its abolition – these acknowledgments complicate the story in necessary ways. Heroism and compromise are not mutually exclusive. Understanding this makes her achievements more, not less, remarkable.
Her work has experienced a gradual rediscovery. The 1915 radium half-life determination remained the authoritative value for decades, cited in countless physics and chemistry texts until improved mass spectrometry refined the measurement in the 1950s and 1960s. Her isotope chemistry investigations, particularly the chlorine work that preserved the periodic table’s quantitative foundations, are recognised by historians of chemistry as pivotal contributions to understanding atomic structure. More recently, feminist historians of science have situated her within broader patterns of the “Matilda Effect” – the erasure of women’s scientific contributions through attribution to male colleagues or outright omission from historical narratives. A 2004 analysis titled “Appreciated Abroad, Depreciated at Home” examined how Norwegian institutions marginalised her despite international acclaim, and in 2018, Oslo Metropolitan University named a building in her honour, belatedly acknowledging her foundational role in Norwegian radiochemistry.
For young women pursuing science today, Gleditsch’s story offers neither simple inspiration nor discouragement, but rather something more valuable: realistic testimony about what advancement requires when systems resist your presence. Her insistence that precision is power – that work done so carefully it cannot be disputed creates authority that gender cannot diminish – remains profoundly relevant. So does her recognition that individual success does not constitute structural change, that creating networks of support and funding for other women is not ancillary to scientific work but essential to it.
Perhaps most urgently, her reflections on the moral debt incurred by those who survive through strategic silence speak directly to contemporary debates about when scientists should speak publicly on matters of justice, when institutional loyalty becomes complicity, and how authority gained through compromise should be deployed. Her 1952 UNESCO resignation over Franco’s Spain models what becomes possible when security is finally achieved: the freedom to refuse participation in institutional decisions that violate conscience.
The half-life of radium-226 is approximately 1,600 years. Gleditsch’s measurement of this constant enabled calculations she could never have imagined – radiation therapies that save lives, environmental monitoring that tracks contamination, nuclear physics that transformed human capability and human danger alike. Her work persists in ways both visible and invisible, cited and uncited, acknowledged and absorbed into the collective knowledge that science becomes.
But perhaps her deepest legacy is this: the insistence that meticulous work matters, that women’s experimental labour must be credited rather than footnoted, that communities of mutual support are not separate from science but foundational to it, and that speaking truth – even when costly, even when late – remains an obligation for those privileged enough to have voices that might be heard. In an era when women in STEM still face barriers Gleditsch would recognise – credibility doubted, contributions minimised, institutional advancement obstructed – her life offers not a blueprint for easy success but rather a map of difficult terrain, marked with the locations of traps, the coordinates of refuge, and the hard-won knowledge of how precision, patience, and principled refusal might together create pathways where none previously existed.
Who have we missed?
This series is all about recovering the voices history left behind – and I’d love your help finding the next one. If there’s a woman in STEM you think deserves to be interviewed in this way – whether a forgotten inventor, unsung technician, or overlooked researcher – please share her story.
Email me at voxmeditantis@gmail.com or leave a comment below with your suggestion – even just a name is a great start. Let’s keep uncovering the women who shaped science and innovation, one conversation at a time.
Editorial Note
This fictional interview transcript is a dramatised reconstruction, created entirely for this project, blending established historical facts about Ellen Gleditsch with imagined dialogue and inner reflection. Readers should approach it with clear understanding of what it is and what it is not.
The biographical details presented – Gleditsch’s work in Marie Curie’s laboratory, her half-life determination for radium-226, her professorship at the University of Oslo, her leadership of the International Federation of University Women, her 1952 UNESCO resignation, and her role during Nazi occupation – are grounded in historical record and scholarly research. Her scientific contributions, publications, and institutional role are accurately represented. The chronology, technical descriptions of her methods, and documented controversies (including disagreements with Irène Curie and resistance to her 1929 professorship) reflect genuine historical events.
However, the conversational exchanges, the specific emotional reflections attributed to Gleditsch, her private thoughts and motivations, and many of the particular details she recalls are fictional creations designed to illuminate probable experiences rather than document confirmed facts. We cannot know precisely how Gleditsch felt about various moments in her career, what calculations she made, or how she privately regarded colleagues. These are imaginative reconstructions grounded in historical context but not verified by primary sources.
The five supplementary questions and responses are entirely fictional, created to explore themes relevant to her life and legacy rather than to record her actual words or thoughts. No interview with Gleditsch on these topics occurred; these are products of creative engagement with her historical significance.
This approach serves a particular purpose: to humanise history, to make visible the inner dimensions of lived experience that official records cannot capture, and to invite readers into genuine encounter with historical complexity. But it does so at the cost of certainty. Readers seeking definitive accounts of Gleditsch’s life should consult biographical scholarship, particularly works examining women’s contributions to radiochemistry and the history of science.
The value of this dramatisation lies not in its factual comprehensiveness but in its invitation to reflection: about how achievement under constraint shapes character, about the costs of survival within unjust systems, about the obligations those who reach security incur to those still vulnerable. These are questions worth exploring, whether through history or through imaginative reconstruction grounded in historical foundation.
Bob Lynn | © 2025 Vox Meditantis. All rights reserved.
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