books & arts The Bohrs’ atom Love, Literature, and that Margrethe did not, contrary to Niels’ stage. For example, Heilbron reconstructs the Quantum Atom: instructions, burn some of the letters! the proceedings at the first Solvay council Niels Bohr’s 1913 Bohr arrived in Cambridge to perform (30 October–3 November 1911), where the Trilogy Revisited research under the guidance of J. J. Thomson, leading physicists of the time — at least, those somewhat in Great Expectations style (both who accepted Walther Nernst’s invitation — By Finn Aaserud and Niels and Margrethe enjoyed Dickens). His gathered to tackle the ‘crisis’ that had arisen J. L. Heilbron initial enthusiasm was gradually replaced from Max Planck’s theory of black-body by disappointment: Thomson and the other radiation. Among the participants was OXFORD UNIV. PRESS: scientists at the Cavendish Laboratory were Rutherford, who, incidentally, was visited 2013. 284PP. $59.95 not much interested in Bohr’s doctoral work, by Bohr immediately after his return to nor in the research he was supposed to do Manchester. Heilbron points out that it is in Cambridge. In March 1912 he moved to difficult not to assume that Rutherford must n 2 April, 1913, Niels Bohr wrote to Manchester to work with Rutherford — a have shared some of the discussions between his wife Margrethe: “My dearest little crucial step in Bohr’s career. the Solvay summit’s participants with Bohr. Oone. Rutherford should only know Among the more prosaic themes in Bohr’s Although Aaserud’s part of the book is free that it is you who have to do it all.” Bohr had correspondence during his time in England from equations, Heilbron does not eschew just had a discussion with Ernest Rutherford are his encounters with people — he seems technical details. Admittedly, the inclusion about his first paper on the quantum theory to have been doing a lot of ‘networking’ and of relevant equations and calculations make of the atom, and can’t wait to finish — with met many famous scientists of the time — half of the book a read for physicists (by the help of Margrethe — the other two parts and his career prospects in Copenhagen. a physicist), but these technicalities add of what would become ‘the Trilogy’. We also learn some of Niels’ views on welcome — if not necessary — value to the Around 200 letters between Niels and philosophy, politics and religion. But the story of Bohr developing and advocating Margrethe that cover the period 1910–1913 main interest of Bohr’s writings is that they his model. And they certainly help to make survive. Together with other letters to provide a glimpse of the ups and downs in Heilbron’s exploration of the connections and from persons close to Bohr, notably his state of mind, and of the development — between Bohr’s written-down musings and Niels’ mother Ellen, brother Harald and or rather, intensification — of his his Trilogy a delightful accomplishment. Aunt Hanna, they provide a unique view relationship with Margrethe. It is touching As the book’s title suggests, literature is of Bohr’s thoughts and feelings — Bohr the to read how they made plans about what to important in their relationship. Both Aaserud physicist (as might be expected) but, even discuss or to read together when they would and Heilbron document and explore this more interestingly, Bohr the loving and be reunited in Denmark, or about Niels aspect in detail. The letters contain several loved (future) husband. asking Margrethe “whether you will help references, particularly to Kierkegaard, One might think that publishing the me sometime to gather some of my small Goethe and Dickens, and the pair often used letters in full would be the preferred thoughts together and help to try whether we quotations to express their feelings. way to go. Instead, in the first part of can perhaps get a little out of them” (which Reading Love, Literature, and the Quantum Love, Literature, and the Quantum she would gladly do throughout her life). Atom brought to mind Michael Frayn’s play Atom, Finn Aaserud, director of the The picture emerging from the letters is Copenhagen — in which the spirits of Niels, Niels Bohr Archive, presents us with that of a dedicated partnership, in which Margrethe and Werner Heisenberg meet a captivating narrative, built around Niels relied on Margrethe to sort out his and discuss the latter’s 1941 visit to Bohr in a fine selection of fragments from the thoughts, and as such develop his ideas into Nazi-occupied Copenhagen — where the correspondence, of the events in Bohr’s scientific publications. A recurring feeling vital role Margrethe played in Niels’ life, both life from shortly after his engagement in Bohr’s letters is that of debt — not only as soulmate and soundboard for ideas and (August 1910) until the publication towards Margrethe, but also his relatives, opinions, is particularly tangible. of the Trilogy (July, September and who too were very loving and supportive. Aaserud’s presentation and analysis of November 1913) — and reprinted in the Although most of the surviving letters are Niels and Margrethe’s correspondence third part of Love, Literature, and the written by Niels (did he perhaps burn the left me with a feeling of deep respect for Quantum Atom. ones he received from Margrethe?), the these two people; it is no surprise that Bohr travelled to England for post- couple’s mutual support and gratitude is Margrethe’s complete commitment, Niels’ doctoral work from September 1911 until evident, and one can only conclude that they never-ceasing gratitude and their shared July 1912, sponsored by a grant from the really must have deeply loved each other. interest in literature led to an extraordinary, Carlsberg Foundation; the couple only The second part of Love, Literature, and the lifelong relationship. Together with saw each other for a short time in the Quantum Atom, written by John Heilbron, Heilbron’s outstanding reworking of the spring when Niels came home for Easter. puts Bohr’s early work and thinking into a history surrounding the creation of Bohr’s As Aaserud points out, it is lucky that broader historical context. From Heilbron’s Trilogy, they make Love, Literature, and the Niels’ creative period took place while masterful account, we come to appreciate the Quantum Atom an excellent read to mark he was in England and Margrethe in state of physics when Bohr appeared on the the centennial of the Bohr atom, or indeed, Denmark, bringing about correspondence scene, which actors and circumstances played as the authors write, the Bohrs’ atom. ❐ that now constitutes such a rich source of a role in Bohr’s trip towards his Trilogy documentation. It is yet more fortunate and how he in turn influenced the physics REVIEWED BY BART VERBERCK 602 NATURE PHYSICS | VOL 9 | OCTOBER 2013 | www.nature.com/naturephysics © 2013 Macmillan Publishers Limited. All rights reserved.