2026-10-08 Noord-Hollands Archief (Haarlem): archive 364, H. A. Lorentz papers
Investigator (Step I), Lorentz-HA, first run. Site: https://noord-hollandsarchief.nl/bronnen/archieven?mivast=236&mizig=210&miadt=236&miview=inv2&milang=nl&micode=364
Found through Google query "Lorentz" archief Noord-Hollands Archief inventaris "Lorentz" Hendrik Antoon correspondence.
The finding aid says it lists 2,212 described items. 742 are digitised (50,779 files). Last change 04-07-2025 [web]. The inventory has three parts: 1. Hendrik Antoon Lorentz; 2. Aletta Catharina Kaiser (his wife); 3. his children Geertruida Luberta, Johanna Wilhelmina and Rudolf Lorentz [web].
The archive's search box takes a URL parameter &mizk_alle=TERM. Searches run, and the hits that matter (item number, then the Dutch description translated; "z.j." = undated):
| Query | Hits that bear on the claims |
|---|---|
| Columbia | one hit only: correspondence file "81 Tur-Vee" (an alphabetical letters file; not opened) |
| electrons | 160 "Institut International de Physique Solvay. Troisième Conseil de Physique. H.A. Lorentz, Notes sur la théorie des électrons", hectographed, 1921. 495 "Calculation of the equation of motion of a particle and of an 'effective particle' at 'effective' times", n.d. |
| relativiteit | 528 lecture notes (collegedictaat) on special relativity, n.d. 534 popular treatise on gravitation, Mercury's perihelion and special relativity, draft, n.d. 585 calculation with the de Broglie/Schrödinger wave equation taking special relativity into account, n.d. 614 fragment of a treatise on general relativity by G. L. Lorentz(?) with notes by Lorentz, n.d. |
| ether | 358 "Theorie van het licht" (Huygens, Fresnel's ether, the elastic ether of Cauchy and Poisson), 1878-1879. 398 "Treatise in which the concept of ether is defended", n.d. 400 calculations on a light ray passing the earth through a vortex in the ether, in connection with Stokes's aberration theory, n.d. 445 treatise of 1899 (electrical oscillations in the ether between parallel conductors, electromagnetic motion of a dielectric, etc.). 459 field around an ion moving in the ether, and the ponderomotive force, n.d. 461 "Beschouwingen over de theorie der ionen" (couples and force of the ether on ions), n.d. 468 energy flow in, and force of the ether on, an electron, n.d. 504 treatise on the ether, matter, the "fluide électrique" and d'Alembert's principle, n.d. |
| elektronen | 322 "Capita selecta 1911-1912" lecture notes (Knudsen flow, Maxwell and Richardson distributions, electrons in metals). 456 Madrid lecture (Real Academia de Ciencias) on electrons and dia- and paramagnetism, draft, 1925. 470, 472 (field of moving electrons from Wiechert's formulae), 474 (mutual action of moving electrons, retardation), 475, 483, 484, 485 "Vraagstukken over de beweging der elektronen" (treatise with transformations), n.d. 486 treatise including "the energy and shape of electrons in collisions in connection with von Laue's theory of relativity, Poincaré's model and energy flow", n.d. 492, 497 (Einstein-de Haas and Barnett experiments), 503 (momentum and energy flow; structure of electrons and atoms). |
| Einstein | Letters from A. Einstein: 1909 (2x) with a Lorentz draft of 1909; 1911 (3x) with 3 Lorentz drafts; 1912 (2x); 1915 (5x); 1916 (5x); 1917 (2x); 1919 (3x) with a Lorentz draft; 1920 (6x); 1921 (3x); 1923 (3x); 1924; 1925 (2x); 1926 (3x) with a manuscript; 1927 (2x); "Zur offenen Feldtheorie" 1923 (as the finding aid spells it; probably Einstein's 1923 "Zur affinen Feldtheorie"). Also 129 press cuttings on Einstein and general relativity, 1920-1921. |
| Kaufmann | Letter from W. Kaufmann, 1904. 501 "Calculations and notes on the deflection of cathode rays in an electromagnetic field and on the longitudinal and transverse mass of the electron in connection with Kaufmann's results", n.d. |
| Bucherer | Letters from A. H. Bucherer: 1902 (3x), 1908, 1909 (2x), 1911 (2x), 1912, 1920, n.d. 135 "Note on the significance of A. H. Bucherer's work for the theory of electricity in connection with the principle of relativity", German, n.d. |
| Michelson | Letters from A. A. Michelson: 1891, 1920, 1921, with a Lorentz draft of 1923. 289 lecture notes "on Miller's repetition of Michelson's experiment, Born and Jordan's matrix mechanics, the virial theorem and other subjects", October 1925 to May 1926. 532 excerpt of Michelson and Gale, "The effect of the earth's rotation on the velocity of light", Nature, 18 April 1925. 595 notes on talks at the "Naturforscherversammlung" on the repetition of Michelson's experiment, the Poynting theorem, electron waves, etc., n.d. |
| Miller | Letters from D. C. Miller: 1906, 1921 (2x), 1926 (see also Morley). |
| Morley | Letter from E. W. Morley, 1904. |
| Poincaré | Excerpts of Poincaré's Comptes rendus notes of 1890 and 1893 (Hertz experiments, propagation of electricity) (items 450, 452, 453); correspondence file "62 Ple-Qui". |
| Voigt | Letters from W. Voigt: 1883, 1888 (2x) with a Lorentz draft, 1896 with a Lorentz draft, 1897-1918 (many), including 1914 (6x) with 2 Lorentz drafts, 1915 (2x), 1916 (6x); see also item 105. |
[web] all of the above: the archive search pages, URL pattern above with &mizk_alle= + term, checked 2026-10-08.
How the finds bear on the claims (leads, not verdicts)
- Claims 1 and 5 (exact transformation, "effective"/local time). Item 495 is a calculation of a particle's equation of motion "at 'effective' times". This is the vocabulary of §§169-176 (effective coordinates, effective time). It may be Lorentz's working paper for the generalized theorem of corresponding states (§§172-176), or a later reworking. It is undated, so the date has to be checked. Items 485 and 528 may hold his own derivations.
- Claim 3 (deformable electron, Kaufmann, Bucherer). Item 501 (Lorentz's calculations on longitudinal and transverse mass "in connection with Kaufmann's results") and the Kaufmann letter of 1904 are the working record behind §179. The Bucherer letters of 1908 and 1909 fall in exactly the period when Lorentz wrote Note 87 of the 1909 edition, which reports Bucherer's 1908 confirmation (see 2026-10-08-internet-archive.md). Item 135 is Lorentz's own note on what Bucherer's work meant for relativity. Item 486 links the electron's energy and shape to Poincaré's model and von Laue.
- Claim 6 (ether "substantiality"; comparison with Einstein). Item 398, "a treatise in which the concept of ether is defended", is the most direct own-work lead on why Lorentz kept the ether. The five Einstein letters of 1915 fall in the year of the [1915] Notes 72 and 75, where Lorentz admits his "chief cause of failure". Whether they bear on those notes is unknown until they are read. (Kox, Scientific Correspondence of H.A. Lorentz, vol. 1, 2008, publishes a selection; see the Google notes.)
- Claim 2 (Michelson-Morley, contraction). Lorentz kept following ether-drift experiments into 1925-1926: item 289 is a lecture on Dayton C. Miller's repetition of Michelson's experiment. Miller reported a non-null drift. Lorentz also corresponded with Miller (1906, 1921, 1926) and Morley (1904). Morley and Miller (1905) is the paper Lorentz cites in §167 for "less than one hundredth part of the computed value".
- Voigt footnote (p.207). Lorentz writes that Voigt's 1887 paper "has escaped my notice all these years". Yet letters from Voigt of 1888 (with a Lorentz draft reply) exist. What they discuss is unknown. This is a record to read, not a contradiction: an 1888 letter need not concern the 1887 Doppler paper.
Not done (next run)
- The items were not opened, so it is not known which are among the 742 digitised. Open 398, 495, 501, 135, 289 and the Einstein 1915 letters and check for scans.
- Searches not yet run in the archive: Fitz Gerald, Abraham, Brace, Rayleigh, Larmor, Minkowski, Laue, Teubner, "corresponding states", "Theory of electrons".