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Felicity Pors, Niels Bohr Archive, Copenhagen, Denmark

"The Niels Bohr Archive, Copenhagen: Holdings, Users, Activities"

I am from the Niels Bohr Archive, Copenhagen, where there is a staff of three. The others are Lis Rasmussen, librarian/secretary, and the director Finn Aaserud, presently lecturing in the U.S. He sends best wishes to his many friends here.  My background is IT and language, and I am very pleased to be here in Edinburgh where I obtained my degree in mathematical science many years ago.

I will start by briefly describing the Niels Bohr Archive, the holdings and current activities. There will also be a short description of plans concerning digitisation of some of the collections.  The Niels Bohr Archive is housed at the Niels Bohr Institute, the physics institute of the University of Copenhagen, in the villa where Niels Bohr and his family lived from 1926 –1932. The Archive has offices on the top floor, I work in what originally was the Bohr children’s nursery. The Archive library is at the top of the old high-tension hall, and the collections are held in the basement.

The Niels Bohr Archive (NBA) holds primary material for the history of modern physics, pertaining in particular to the early development of quantum mechanics and the life and career of Niels Bohr (1885-1962). Although the NBA has existed since shortly after Bohr's death in 1962, its future was only secured at the centennial of Bohr's birth in 1985, when a deed of gift from Bohr’s wife, Margrethe, provided the opportunity to establish the NBA as an independent not-for-profit institution. Since 1985, the NBA has had its own board of directors and has received a fixed annual sum for running expenses, presently from the Danish Ministry of Science, Technology and Innovation; the NBA has also made ample use of its privilege to apply for project support from private sources.

The core of the collections comprises Bohr's scientific correspondence (6000 letters and drafts) and manuscripts (500 units). This material was catalogued and microfilmed in the early 1960s as part of the Archive for History of Quantum Physics (AHQP), a project sponsored by the American Philosophical Society and the American Physical Society. The outcome was 290 microfilms of various relevant historical material, which have been placed in several repositories world-wide, including the NBA. Quite often the younger generations of history of science researchers seem to be unaware of the availability of the AHQP worldwide. It can also be noted that these microfilms, now 40 years old, show no signs of age.  This is one of the records on microfilm:

The major collections of the Niels Bohr Archive not on microfilm are:

· Bohr Scientific Correspondence, Supplement

· Manuscripts, other authors

· Bohr General Correspondence

· Bohr Private Correspondence

· Bohr Political Correspondence

· Harald Bohr Correspondence

· Bohr Newspaper Clippings

· Sound recordings of Niels Bohr lectures and interviews

· Niels Bohr Film Collection

In addition, the NBA houses several historical collections that cannot be consulted elsewhere. Thus, in 1985 the Bohr family donated the bulk of Bohr's private correspondence, which includes letters to and from central personalities in culture and politics inside and outside Denmark. The equally extensive ‘Bohr General Correspondence’ documents Bohr's substantial administrative involvement. The Political Correspondence was made available in 1999.

NBA also has collections of material originating from other physicists. Scientific Correspondence and Papers of:

· George Hevesy (1885-1966)

· Léon Rosenfeld (1904-1974)

· Aage Bohr (1922- )

· Oskar Klein (1894-1977)

· Hans Anton Kramers (1894-1952)

· Allan R. Mackintosh (1936-1995)

· Christian Møller (1904-1980)

· Bernard Peters (1910-1993)

· Stefan Rozental (1903-1994)

Among papers of Bohr’s closest colleagues deposited in the NBA, only the Scientific Correspondence of George Hevesy and H.A. Kramers has been microfilmed, but the papers of among others Léon Rosenfeld, Christian Møller and  Oskar Klein are also of great historical interest and frequently referred to.

Some papers of more recent origin - notably those of Aage Bohr, Niels Bohr's son, and of solid-state physicist Allan Mackintosh have also been deposited. These collections have been organised and described with the help of a grant from the American Institute of Physics (AIP). A more complete list as well as descriptions of the collections are to be found on the NBA website. ( The web also shows a catalogue of the large collection of photographs relating to Bohr's career, this collection is an especially popular resource. The NBA library catalogue is also accessible from the website.

The Archive makes the collections available to users, accommodating requests for information and material.

The NBA continues the publication - through Elsevier - of the Niels Bohr Collected Works, the first volume of which appeared in 1972. Volume 11 (edited by Finn Aaserud and the only one remaining) will cover Bohr's activities outside science and philosophy, prominently including some of Bohr's previously unpublished writings on his idea of an ‘open world’, developed during and after World War II.

Since 1999, the NBA increased its special activities aimed at disseminating natural science for the public, particularly gymnasium (high-school) students. This is done in collaboration with the staff of the NB Institute who give introductions to physics topics and demonstrations of practical work in the basement labs as a supplement to the science history talks and tours of the Institute supplied by the NBA. The guided tour includes a visit to Niels Bohr’s office which remains more or less as it was in 1962 and to the original Auditorium A.

The NBA also has an ongoing History of Science Seminar where prominent scholars from far and near are invited to talk about their work, either when they are close enough to Copenhagen so that we can afford to pay their ticket or when they are visiting the Archive anyway in order to conduct research in our collections. These talks although held at irregular intervals have made the Archive more well-known in Danish circles as well as strengthening relations with the international history of science community. Recent speakers have been Ruth Sime who talked about Lise Meitner and Graham Farmelo, whose topic was P.A.M. Dirac.

Recent activities at the NBA

The play Copenhagen by Michael Frayn has directed much interest towards the NBA. In 2002 the NBA organised the release of Bohr's notes and drafts pertaining to Werner Heisenberg's visit to Copenhagen in September 1941. The documents were presented in February 2002 on the NBA website ( and as a special edition of the journal Naturens Verden.

The release provoked substantial international interest and gave rise in particular to a large increase in the number of applications to the NBA as regards both general information and use of archival material. A couple of days after the release on 6 February 2002, the number of daily hits on the NBA's home page rose from about 50 to 15,000 and has subsequently stabilised at around 500 per day.  As one of many consequences of the release, NBA participated in the documentary film ‘The Copenhagen Fallout’ made by BBC and KCET television about the historical background for Michael Frayn’s play. This documentary and the TV-version of the Copenhagen play were broadcast in Britain and the US in September 2002.

Future plans

The Archive has successfully applied for a grant from the Danish Lottery Fund

· to digitise the sound and film collections

· to convert the numerous and various types of collection descriptions to a standard format. The resulting records will be made available on the NBA website.

· to have a pilot scanning project, whereby the papers in the Bohr Political Correspondence will be made available to researchers in digital form

These projects will be carried out over the next three years - the digitisation of the sound and film collections will be outsourced.