Friday, . Science historian Anne Kox receives a call from a notary. In Jan Zeeman’s estate he had found papers that appeared to belong to the Dutch physicist Hendrik Lorentz. The notary wanted to have an expert look at them, to prevent them from being wrongly thrown away.
What Kox found in that large mansion on Amsterdam’s Stadhouderskade was a gold mine, one of the most complete archives of a scientist ever preserved. It was the legacy of the Dutch physicist and Nobel Prize winner Pieter Zeeman (1865-1943). Almost forty years later, Kox and his wife Henriëtte Schatz look back on that strange Friday afternoon: “It was incredible chaos. There were rusted bicycles everywhere, still equipped with carbide lamps. Stacks of newspapers and magazines dating back to the forties. In the back room half the ceiling had fallen due to a leak and my leg went straight through the floor. Son Jan Zeeman had lived there all his life, but had ended up as a lonely person. hermit.”
Fortunately, he had not thrown anything away all those years – father Pieter had died in 1943 – just as his father had not done so during his lifetime. In addition to train tickets, receipts, bills and whatnot, around 12,000 letters were found, from relatives and friends as well as from scientists. And, much more importantly, also letters from Zeeman himself, who always neatly kept and stored the drafts of the letters he sent away.
Kox: “All kinds of other scientific treasures also emerged from the cupboards, such as meticulous scientific notes, complete laboratory reports, lecture notes, you name it. Zeeman’s entire scientific archive was still there, dusty and messy perhaps, but completely intact!”
The archive as found in 1989 in Zeeman’s home.
Photo HF Schatz
Since then, everything has been transferred to the North Holland archives in Haarlem, where an inventory was made so that it became accessible for scientific research. Schatz: “That was made possible by a fund that Annie, Zeeman’s youngest daughter, set up a year after the find with her father’s name.”
The aim of the fund is to promote research into the history of science, in particular in the field of physics. Since then, Kox has published here and there about Zeeman’s life and work. Through his work as senior editor However, he hardly had time to do his own research during the Einstein Papers Project, the publication of all of Albert Einstein’s writings and letters. And after the publication of the biography of Hendrik Antoon Lorentz in 2019, he had had enough of writing yet another biography. Kox: “It was Henriëtte who convinced me that there was a beautiful story in all that Zeeman archive material. And so we started in the middle of the corona period.”
The result recently appeared: which he wrote together with Schatz, Pieter Zeeman, From village boy to Nobel Prize winner.
Pieter Zeeman was born on May 25, 1865 in a liberal Protestant pastor’s family in Zonnemaire, Zeeland. From an early age he had a great interest in science, which was reflected in accurately observing and describing living nature and the starry sky. In the autumn of 1882 this led to an unexpected result, when he observed the northern lights on the roof of the shed for several nights. His observations even ended up in the magazine through the grapevine Naturewhich, as a seventeen-year-old, earned him a letter from an English scientist addressed to “Professor Zeeman, Zonnemaire”. Of course that was also kept.
A more or less secret scientific excursion led to his greatest discovery
With an HBS diploma and a successful entrance exam in Greek and Latin, he registered as a physics student in Leiden in 1885. A meeting with professor Heike Kamerlingh Onnes, who liked the young Zeeman, had led him to that choice. He also quickly became on friendly terms with his Leiden colleague Hendrik Antoon Lorentz and because he studied seriously and quickly, he was given an assistantship, the ideal way to complete his academic training with a PhD.
The research in Leiden had two different directions. One was the study of the behavior of gases and liquids – research that would win Onnes a Nobel Prize in 1913 for liquefying helium, making Leiden the coldest place in the world. The other was the study of optical phenomena. Zeeman did his PhD research in the latter area, on the interaction between magnetic fields and light.
Kox: “A more or less secret scientific excursion – laboratory director Kamerlingh Onnes was on holiday – led to his greatest discovery, which would earn him eternal fame and a Nobel Prize.” Each substance, when heated, emits light of different colors, which is reflected in a characteristic spectrum.
Zeeman discovered that the color lines in that spectrum broaden and even split in a magnetic field. A completely new phenomenon, for which Lorentz was immediately able to provide a conclusive explanation. The Zeeman effect pointed to the presence of negatively charged particles in atoms, which later turned out to be electrons. The physics world was amazed.
This earned Zeeman an appointment as lecturer at the then youngest university in the Netherlands, the Municipal University of Amsterdam. Despite a number of lucrative foreign offers, he remained there all his life, as professor and director of the physics laboratory.
Facsimiles of original construction drawings from the 1960s for an extension of the Zeeman Laboratory on the Amsterdam Plantage Muidergracht. The laboratory was built in 1923.
Photo Paul van Riel/ANP
There he set up a research program almost from scratch. He struggled with the circumstances there. The proximity of a tram line and a busy traffic artery made the precision research he advocated almost impossible. Every now and then he went to the basement of his country house near Zeist for experiments. He also paid for instruments or an assistant’s salary from his own pocket when the municipality once again refused to provide money.
Now he could easily afford that because his wife Jo, a sister of a student friend, came from a wealthy entrepreneurial family from Dordrecht. When her father died, she had received a large inheritance, to which the money from the Nobel Prize was added in 1902. Later, Zeeman would also amass an enormous fortune through all kinds of investments. He easily accepted all these luxuries – he did not pay much attention to others who had a more difficult time.
In any case, the family was not a very warm environment. Kox and Schatz dwell extensively on the rather dreary situation of wife Jo, “languishing in her boudoir” next to her hardworking, but authoritarian and coercive husband. Schatz: “She was a quick and bright girl who was simply not given the opportunity to develop. When Zeeman had to stay in bed for a few weeks with scarlet fever, she completely revived and it was only then that you saw what she was capable of. The upbringing of their three daughters and a son rested largely on her shoulders. Son Jan in particular caused a lot of problems from his early childhood and later he even exerted a kind of terror with his frequent outbursts of anger. His sisters were terrified of him.”
Very accurate and precise
Jo suffered from depression – like her father and one of her brothers – and had little interest in activities other than buying new clothes or going on luxury trips. Yet she tried to fulfill her role as wife as best she could. In turn, Zeeman did not show much personal involvement with his family – although that was certainly not unusual for a head of family at that time. He happily retreated to his laboratory, working on his career. The children did not develop well, none of the four ever found a life partner and none of them would have made it without the financial support (and later inheritance) of their parents.
Schatz: “Only Sister Annie tried with all her might to make what could be done of the emotional mess that it had gradually become there on the Stadhouderskade.” Besides Zeeman, there was simply not much room for his wife and children, “because little could grow in the shade of this tall tree.”
Despite his great efforts, Zeeman’s later scientific work did not yield much. Kox: “It is not good for a person to make such a major discovery so early. Zeeman therefore started to focus on what he was good at: very accurate and precise measurements.” He was also a member of the Academy of Sciences and a number of committees, but he did so in a very inconspicuous manner and often in the shadow of Lorentz. It did make itself felt in both scientific and political areas – for example during the First World War – and grew into the éminence grise of international physics.
Schatz: “We did not just want to tell a largely chronological life story, but also to sketch how such a family from the upper middle class lived in a rapidly developing city like Amsterdam. Or how isolated his life was in a remote corner like Zeeland.”
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