Ehrenfest Library
INVENTORY OF DOCUMENTS AT THE EHRENFEST LIBRARY
INSTITUTE- LORENTZ, UNIVERSITY OF LEIDEN
These documents were found by Rowdy Boeyink, as part of a graduate project, in Paul Ehrenfest's library in the summer of 2005 and inventoried by him. They had gone unnoticed for years amid books and journals. In April 2013, the documents were transferred to the Museum Boerhaave to become part of the complete Ehrenfest collection. The books and journals themselves remained behind at the Institute-Lorentz.
Most of the documents have been scanned by Carlo Beenakker. The scans can be found at
http://www.lorentz.leidenuniv.nl/history/Ehrenfest_archive/full_size_scans/
Boeyink's find caused quite a stir because of the Einstein manuscripts that were among the documents. These documents were transferred to the Leiden University Library shortly after the find in 2005 (archive number BPL 3545) and are therefore not in the Boerhaave collection. More information on the discovery and significance of the Einstein manuscripts can be found here:
http://www.lorentz.leidenuniv.nl/history/Einstein_archive/
Later Friedmann manuscripts have also attracted some attention, see
http://www.lorentz.leidenuniv.nl/history/Friedmann_archive/
Additional documents from the Ehrenfest library (numbers 62 and following), were collected and scanned by Carlo Beenakker on the occasion of its move from the Oort building to the Snellius building (April 2025). The documents are kept in the Instituut-Lorentz archive.
01. Handwritten article " Randwinkel gesättigter Lösungen an Kristallen "
Dated: about 1896, published in Naturwissenschaftliche Rundschau 14, 383 (1899)
Author: Agnes Pockels
Size: 4 pages double-sided, German
02. Handwritten letter to M. Planck (Herr Geheimrat)
Dated: 05/04/1912
Author: P. Ehrenfest
Size: 1 side double-sided, German
---> Scanned as Ehrenfest_1912
03. Typed manuscript " Kovarianzeigenschaften der Feldgleichungen der auf die verallgemeinerte Relativitätstheorie gegründeten Gravitationstheorie "
Dated: Zurich, undated (circa 1914), published in Zeitschrift für Mathematik und Physik 63, 215 (1914)
Author: A. Einstein and M. Grossmann
Size: 13 pages single-sided, German - in University Library
---> Scanned as Einstein_1914_typescript
04. Typed letter to Dieke/Goudsmit/Uhlenbeck
Dated: Leiden, 16/05/1930 (probably never sent).
Author: P. Ehrenfest
Size: 2 pages single-sided, German
---> Scanned as Ehrenfest_1930
05. Handwritten letter accompanying printed letter on education at the Gymnasium
Dated: 23/05/1917
Author: J. Hooykaas
Size: 1 side double-sided, Dutch
06. Original handwritten manuscript " On the adiabatic invariants of mechanical systems "
Dated: August 1917
Author: J.M. Burgers (unsigned) + notes by second person (N. Bohr?)
Size: 17 pages single-sided, English
---> Scanned as Burgers_1917
07. Handwritten correction to proof "Schallausbreitung in teilweise dissoziierten Gasen"
Dated: April 1920 (undated), published in Sitzungsberichte der Preußischen Akademie der Wissenschaften, Berlin, April 8, 1920, pp. 380-385.
Author: A. Einstein
Size: 8 pages single-sided, German - in University Library
---> Scanned as Einstein_1920_page_proof
08. Handwritten letter including report of lecture by Niels Bohr
Dated: 29/03/1921 & undated
Author: H.A. Kramers
Size: 3 sides double-sided, Dutch & 5 sides single-sided, English
---> Scanned as Kramers_1921a and Kramers_1921c
09. Handwritten letter
Dated: Copenhagen, 02/04/1921
Author: H.A. Kramers
Size: 2 sides double-sided, Dutch
---> Scanned as Kramers_1921b
10. Article "Atomic Structure" with notes by Paul Ehrenfest
Dated: 16/09/1921
Author: N. Bohr
Size: 4 sides single-sided, English
---> Scanned as Bohr_1921
11. Handwritten letter including article "Ueber die räumliche Anschauungsform"
Dated: Leipzig, 22/10/1921, the article was published in Vierteljahrsschrift für wissenschaftliche Philosophie und Soziologie 23 (neue Folge 8), 31-65 (1909)
Author: G. Jaffe
Size: 2 pages double-sided, German
12. Handwritten letter including article "On the curvature of space"
Dated: 03/06/1922 & 29/05/1922, published in German in Zeitschrift für Physik 10, 377 (1922).
Author: A. Friedman
Size: 1 side single-sided, Russian & 11 sides single-sided, Russian
---> Scanned as Friedmann_1922_b
13. Manuscript "On the question of the geometry of curved space" with some notes by P. Ehrenfest and accompanying handwritten letter by J.A. Schouten and typed letter by A. Friedman
Dated: 15/04/1922 & 29/06/1922 & 15/06/1922 (the manuscript was never published)
Author: A. Friedman & J.A. Schouten
Size: 28 sides single-sided, Russian & 1 side double-sided, Dutch & 5 sides, Russian [see also No. 45].
---> Scanned as Friedmann_1922_a and Schouten_1922 and Friedmann_1922c
14. Article "Sur les fonctions quasiperiodiques"
Dated: undated (after 1922) (presumably never published)
Author: Harald Bohr
Size: 3 sides single-sided, French
---> Scanned as H_Bohr_19XX
15. Handwritten letter
Dated: Delft, 09/02/1923
Author: J. Burgers
Size: 2 pages double-sided, Dutch
---> Scanned as Burgers_1923a
16. Handwritten letter
Dated: Delft, 17/02/1923
Author: J. Burgers
Size: 2 pages double-sided, Dutch
---> Scanned as Burgers_1923b
17. Handwritten letter
Dated: Delft, 20/02/1923
Author: J. Burgers
Size: 1 side double-sided, Dutch
---> Scanned as Burgers _1923c
18. Handwritten letter and handwritten article "Ueber die Abhängigkeit der Entropie von der Teilchenzahl"
Dated: Berlin, 28/06/1923 (presumably never published).
Author: R. Becker
Size: 1 side single-sided & 6 sides single-sided, German
19. Typed manuscript "A Survey of the Radiation Hypothesis of Thermal Chemical Change", along with publication from Phil. Mag. 46, 327 (1923)
Dated: August 1923 (presumably never published)
Author: W.C.M. Lewis
Size: manuscript is 20 pages single-spaced, English (the publication has some notes by Ehrenfest)
---> Scanned as Lewis_1923 and Lewis_1923_publication
20. Drawn schematic of atomic collisions (on the back of a publication by R.H. Fowler)
Dated: after February 1924
Author: P. Ehrenfest
Size: 1 side
---> Scanned as Ehrenfest_1924
21. Handwritten letter including article "Ueber die Beeinflussung der Adsorption von Neutralmolekülen durch ein elektrisches Feld“
Dated: 08/03/1926; the article was published in Zeitschrift für Physik 35, 792 (1926)
Author: A. Frumkin
Size: 1 side double-sided, Russian
22. Handwritten manuscript "Quantentheorie des einatomigen idealen Gases - Zweite Abhandlung".
Dated: December 1924, published in Sitzungsberichte der Preußischen Akademie der Wissenschaften, Berlin, January 8, 1925, pp. 3-14.
Author: Albert Einstein
Size: 16 pages single-sided, German - in the University Library
---> Scanned as Einstein_1925_manuscript, see also Einstein_1925_publication
23. Handwritten note to article "Bands in the secondary spectrum of Hydrogen"
Dated: February 1925; the note was presumably never published, the article itself is in Proc. Kon. Akad. Sciences. (Amsterdam) 27, 490-500 (1924)
Author: G.H. Dieke (unsigned)
Size: 4 sides single-sided, English
---> Scanned as Dieke_1925 (see also Dieke_1926)
24. Handwritten letter accompanying article "Ueber die bedeutung des Gasgehalts von Metallen für einige elektrische Erscheinungen."
Dated: 22/05/1925, published in Zeitschrift für Physik 31, 277 (1925).
Author: A. Janitzky
Size: 1 side double-sided, Russian
25. Handwritten letter
Dated: Vienna, 13/04/1926
Author: Ph. Gross
Size: 1 side, German
26. Typed note "Sur les équations de Dirac dans la théorie de relativité générale."
Dated: undated (after 1926), published in Compte Rendu Academie Science Paris 189, 25 (1929)
Author: V. Fock
Size: 3 sides single-sided, French
27. Handwritten letter including typed article "Einige Anwendungen der Schwingungsgleichung der Quantentheorie"
Dated: 10/11/1927 (presumably unpublished)
Author: O. Klein & P. Ehrenfest, O. Klein and G.E. Uhlenbeck
Size: 6 pages single-sided, German & 11 pages single-sided, German
---> Scanned as Klein_1927a and Klein_1927b
28. Typed cheat sheet for laudatio at promotion of S. Goudsmit
Dated: Autumn 1927
Author: P. Ehrenfest (unsigned)
Size : 1 side single-sided, Dutch
---> Scanned as Ehrenfest_1927
29. Handwritten letter accompanying article "On the propagation of electromagnetic vibrations”
Dated: 09/12/1927
Author: G.J. Elias
Size: 2 pages double-sided, Dutch
30. Farewell address H.A. Lorentz with handwritten notes in preparation.
Dated: February 1928
Author: P. Ehrenfest
Size: various notes, German
---> Scanned as Ehrenfest_1928
31. Typed manuscript "Ueber das H-theorem von Anwachsen der Entropie vom Standpunkt der neuen Quantenmechanik"
Dated: July 1928, published in P. Debye, Probleme der modernen Physik, Hirzel, Leipzig, 1928
Author: W. Pauli Jr.
Size: 25 pages single-sided, German
---> Scanned as Pauli_1928
32. Typed letter to P. Ehrenfest including articles
Dated: Lahore, 11/10/1928
Author: S.S. Bhatnagar
Size: 1 side single-sided, English
33. Handwritten letter with publications
Dated: Sofia, 20/05 >1929
Author: R. Zaycoff
Size: 1 side single-sided, German
34. Handwritten letter including article "The Magnetic Electron"
Dated: Tisvilde, 22/05/1929 & undated
Author: N. Bohr
Size: 1 side single-sided, German & 5 sides single-sided, English
---> Scanned as Bohr_1929a and Bohr_1929b
35. Handwritten letter including manuscript by N. Bohr "Wirkungsquantum und Naturschreibung"
Dated: Copenhagen, 14/06/1929 & 1929
Author: H. Casimir & N. Bohr
Size: 1 side double-sided, Dutch & 8 sides single-sided, German
---> Scanned as Bohr_1929c and Casimir_1929
36. Handwritten letter including separate calculations
Dated: Leiden, 08/07/1929
Author: A.J. Rutgers
Size: 2 sides double-sided, Dutch & 3 sides single-sided
---> Scanned as Rutgers_1929
37. Typed letter accompanying return of article from Ehrenfest
Dated: 24/08/1929
Author: Hans Meyer
Size: 1 side single-sided
38. Two handwritten postcards.
Dated: 13/09/1929 & 23/09/1929
Author: W. Alexandrow
Size: 2 postcards, German
39. Two handwritten letters and scientific note attached to Einstein's 1928 publication "Neue möglichkeit für eine einheitliche Feldtheorie von Gravitation und Elektrizität"
Dated: letters: Göttingen, 07/11/1929 & 16/11/1929, note undated
Author: Tanja Ehrenfest-van Aardenne (unsigned)
Size: 10 pages double-sided & 8 pages single-sided, German/Russian
---> Scanned as T_Ehrenfest_1929a and T_Ehrenfest_1929b
40. Handwritten letter including article (reprint) with typed notes
Dated: 03/01/1931; the article is from W.J. de Haas and C.J. Gorter, Verslagen Akad. Amsterdam 33, 1101-1105 (1930).
Author: W.J. de Haas
Size: 1 side double-sided, Dutch & various notes by Ehrenfest
---> Scanned as DeHaas_1931
41. Satirical play "Faust" in three parts on atomic physics with drawings
Dated: 1931
Author: N. Hahn
Size: 17 pages single-sided, German/French
---> Scanned as Faust_1932
42. Handwritten letter and article "Ueber relativistische Statik"
Dated: undated, published in Annalen der Physik 341, 779-795, (1911)
Author: P. Epstein
Size: 1 side & 20 sides single-sided, German
43. Handwritten (part of an) article "Bemerkungen zu den mechanischen und elektrischen Analogien zum II. Wärmesatz"
Dated: undated
Author: P. Ehrenfest (unsigned)
Size: 3 pages plus 4 pages of small calculations, German
---> Scanned as Ehrenfest_19XXa
44. Lecture notes and preparations.
Dated: undated
Author: P. Ehrenfest
Size: 18 pages single-sided, German
---> Scanned as Ehrenfest_19XXb, Ehrenfest_19XXc, Ehrenfest_19XXd
45. Handwritten letter to Weyl
Dated: undated
Author: A. Friedman
Size: 3 sides double-sided [belongs to No. 13].
---> Scanned as Friedmann_19XX
46. 'Carbon-copy' of Manuscript "Ueber einige Wirkungen von Strahlen III"
Dated: Frankfurt a/M., undated, published in Zeitschrift für Physik (1923)
Author: F. Dessauer
Size: 15 sides single-sided
47. 'carbon-copy' of article "Ueber die Differentialgeometrie einer Hermitischen Differentialform und ihre Beziehungen zu den Feldgleichungen der Physik" with notes by Ehrenfest
Dated: undated, published in Verslagen Akad. Amsterdam 32, 60-64 (1929).
Author: J.A. Schouten and D. van Dantzig
Size: 8 pages single-sided, German
48. 'carbon-copy' of article "Ueber die in der Wellengleichung verwendeten hyperkomplexen Zahlen"
Dated: undated, published in Verslagen Akad. Amsterdam 32, 105-108 (1929).
Author: J.A. Schouten
Size: 7 pages single-sided, German
49. Handwritten notes on various publications in classical physics.
Dated: undated, probably around 1900
Author: unsigned, probably P. Ehrenfest
Size: 7 sheets with 4 sides described, German
---> Scanned as Unknown_19XXb
50. Handwritten manuscript "What role does the trinity of dimensions of space play in the main laws of physics ?"
Dated: undated, published in Verslagen Akad. Amsterdam 26, 105 (1917)
Author: P. Ehrenfest
Size: 11 pages single-sided, Dutch
---> Scanned as Ehrenfest_1917
51. Typed article "Ueber das thermische Gleichgewicht zwischen Quantenatomen und Hohlraumstrahlung"
Dated: undated, published in Zeitschrift für Physik 33, 649-655 (1925).
Author: P. Jordan
Size: 9 pages single-sided, German
52. Part of a handwritten letter to P. Ehrenfest (on matrix mechanics)
Dated: undated
Author: H.B.G. Casimir
Size: 1 side single-sided, Dutch
---> Scanned as Casimir_19XX
53. Handwritten article "The general basis of the Rydberg-Ritz Formula."
Dated: undated
Author: unsigned
Size: 3 sides single-sided, English
---> Scanned as Unknown_19XXa
54. Typed manuscript "La Théorie Nouvelle de M. Einstein et la Théorie des Quanta"
Dated: undated, published in Compte Rendu Academie Science Paris 188, 1598-1600 (1929)
Author: M.I. Tamm
Size: 3 sides single-sided, French
55. Typed manuscript "Bemerkungen zur Einsteinschen einheitlichen Feldtheorie"
Dated: Moscow, undated, published in Zeitschrift für Physik 1929 57, 354-366 (1929).
Author: M.I. Tamm and M. Leontowitsch
Size: 14 pages single-sided, German
56. Various articles and journals signed by Einstein
Dated: various
Author: A. Einstein
Size: different
57. Several articles signed by Ehrenfest and Bohr with notes by P. Ehrenfest
Dated: various
Author: N. Bohr + A. Einstein
Size: different
58. Handwritten summary of Ehrenfest's publications up to 1922.
Dated: undated
Author: unsigned
Size: 3 sides double-sided
---> Scanned as Ehrenfest_publications
59. Handwritten and typed notes.
Dated: undated
Author: P. Ehrenfest
Size:
---> Scanned as Ehrenfest_varia
60. Handwritten mathematical notes by P. Ehrenfest (and second person?)
Dated: undated
Author: P. Ehrenfest & unknown author
Size: 19 sides double-sided
---> Scanned as Ehrenfest_varia
61. 'carbon-copy' of typed letter with handwritten salutation
Dated: 28/05/?? (The original is a Boerhaave archival document from 1921)
Author: N. Bohr
Size: 6 pages single-sided, German
---> Scanned as Bohr_19XX
62. Typewritten manuscript by N. Bohr, “The Difference between Series Spectra of Isotopes”
undated, published in Nature 109, 746 (1922). Two pages in English, some scribbles on the back.
••• Scanned as Bohr_1922
63. Handwritten notes by Ehrenfest on a problem in hydrodynamics and a letter to Jan Burgers
Undated, because of a reference to Ehrenfest’s postdoc Trkal they are likely from late 1919/early 1920. Two pages of notes on a paper by Clebsch, eight pages of notes on a paper by Lamb, six pages of notes on a paper by Borchardt, plus a four-page letter to Burgers, inviting him to take the lead in this project. The notes were found in the book by Love “Lehrbuch der Elastizität”, cited by Ehrenfest.
••• Scanned as Ehrenfest_1919
64. Handwritten notes by Ehrenfest on electromagnetism and a letter to Karel Nuyens
Dated May 6, 1929. Eight pages on notes, based on Lorentz’s dissertation, plus a two-page letter to K.M. Nuyens, urging him to summarize Lorentz’s notation. Nuyens studied with Ehrenfest before moving to Brussels for a Ph.D.
••• Scanned as Ehrenfest_1929
65. Handwritten notes by Tatjana Afanassjewa
These notes were found in the collected works of Herz. The book was gifted to Tatjana by Walther Ritz, on the occasion of his Ph.D. in Göttingen, 19 December 1902.
••• Scanned as Afanassjewa_1902
66. Comments by Tanja Ehrenfest on Goudsmit’s thesis
Tanja Ehrenfest (who signed T’ to distinguish her from her mother) wrote these two pages of notes on Goudsmit’s thesis, perhaps to interrogate Goudsmit during the defense (July 7, 1927).
••• Scanned as T_Ehrenfest_on_Goudsmit
67. Typewritten manuscript by Maria Göppert, “Über die Wahrscheinlichkeit des Zusammenwirkens zweier Lichtquanten in einem Elementarakt”
Undated, published in Naturwissenschaften 17, 932, (1929). Three pages in German, handwritten formulas and illustrations.
••• Scanned as Goeppert_1929
68. Handwritten notes by Ehrenfest on classical mechanics
Four pages of handwritten notes found in Helmholtz’ “Abhandlungen”.
••• Scanned as Helmholtz_abhandlungen
69. Letter from V. Fock to Ehrenfest, dated 16 January 1930
In response to a query by Ehrenfest on creation/annihilation operators and the quantization of the harmonic oscillator, Fock discusses these in 7 handwritten pages, in German. The notes are an early derivation of the spectrum using operator algebra, rather than differential equations.
••• Scanned as Fock_1930
70. Handwritten notes by Ehrenfest on Dirac’s quantum mechanics
Notes in the volume of collected reprints by Dirac, 6 pages in German, one page in Dutch in a different handwriting.
••• Scanned as Ehrenfest_on_Dirac
71. Handwritten notes by Ehrenfest and others on radioactivity
Four pages of handwritten notes in Dutch, summary of literature on radioactivity. Two more pages in German, in Ehrenfest’s handwriting. All undated. These sheets were found in the book by Ebbe Rasmussen (1932) on “Radiumemanation”.
••• Scanned as Ehrenfest_and_others_notes_on_radiactivity
72. Handwritten notes by Ehrenfest on Schrödinger’s 1921 paper
Notes by Ehrenfest on the back of Schrödinger’s “Versuch zur modellmässen Deutung des Terms der scharfen Nebenserien” (1921).
••• Scanned as Ehrenfest_on_Schrodinger
73. Handwritten notes by Ehrenfest on Van Leeuwen’s thesis on magnetism
Three pages of handwritten notes at the back of the thesis, plus seven pages of loose notes. The notes are entitled “Einfluss der mechanischen Trägheit auf die diamagnetische Reaction eines Electric Ringes”. Dated August 9, 1925.
••• Scanned as Ehrenfest_1925
74. Handwritten notes by T. Ehrenfest-Afanassjewa on Tolman’s theory of relativity
Four pages of handwritten notes on relativity by Tatjana Ehrenfest-Afanssjewa, in German, dated August 25, 1915. The notes are entitled “Einge Einzelheiten der T. Theorie”; the “T” is referred to as “Tolman” in the notes.
••• Scanned as Afanassjewa_1915
75.Typewritten manuscript by T. Ehrenfest-Afanassjewa on general relativity
Ten pages of typewritten text on “In welchem Sinne ist die Metrik des Raumes bestimmt?”, a critical discussion of Einstein’s general relativity. The text is written for a friend, “Mannour..”, dated November 3, 1955. Together with correspondence with Droste and van de Woude, it was found in Droste’s thesis.
••• Scanned as Afanassjewa_1955
76. Letter from J. Droste to T. Ehrenfest-Afanassjewa
Two handwritten pages in Dutch, dated April 4, 1956, in response to a question on general relativity.
••• Scanned as Droste_1956
77. Letters from W. van der Woude to T. Ehrenfest-Afanassjewa
Three handwritten letters in Dutch, dated July 2, 7, and 8 1956, in response to a question on general relativity. Willem van der Woude was a retired professor of mathematics in Leiden, a colleague of Droste.
••• Scanned as vanderWoude_1956