Emil Wiechert was well known during his lifetime as Professor of Geophysics at the Georg-August-Universität in Göttingen and Director of the Geophysical Institute there. He made many significant contributions to geophysics and seismology, and is highly respected by present-day geophysicists for his research and organizational contributions to the development of geophysics and seismology as major scientific disciplines. On the other hand, his contributions to fundamental physics—cathode rays, the discovery of the electron, the Liénard–Wiechert potentials, his electron theory—are unknown to many physicists today. This article presents Wiechert’s life, achievements in physics, and relationship to well-known physicists like Arnold Sommerfeld, Hendrik Lorentz, and Woldemar Voigt, to enable contemporary physicists to know better Wiechert’s important contributions to pure physics, and to appreciate more fully his role in the history of physics.
REFERENCES
1.
Freeman J.
Dyson
, Infinite in All Directions (Harper and Row, New York, 1988), p. 36.Freeman J.
Dyson
, The quote is a translation from Emil Wiechert’s paper, “Die Theorie der Elektrodynamik und die Röntgen’sche Entdeckung
,” Schriften der Physikalisch-Ökonomischen Gesellschaft zu Königsberg
37
, 1
–48
(1896
); on p. 3.2.
Res
Jost
, “Boltzmann und Planck: Die Krise der Atomismus um die Jahrhundertwende und ihre Überwindung durch Einstein
,” Lect. Notes Phys.
100
, 128
–145
(1979
). (Springer-Verlag, New York); on Wiechert see pp. 133–134.3.
Among the better accounts of Wiechert’s life and scientific achievements are Gustav H. Angenheister’s biography in Deutsches Biographisches Jahrbuch (Deutsches Verlag-Anstalt, Stuttgart and Berlin, 1928), Band 10, pp. 294–302;
Wilfried Schröder, “Ein handschriftlicher Lebenslauf von Emil Wiechert,” in Physics and Geophysics with Special Historical Case Studies, collected and edited by Wilfried Schröder (Bremen-Roennebeck, Germany, Interdivisional Commission on History, International Association for Geomagnetism and Aeronomics [IAGA], 1997), pp. 173–177;
Wilfried Schröder, “Emil Wiechert,” in Reflections on Physics and Geophysics, edited by Wilfried Schröder and Hans-Jürgen Treder (Interdivisional Commission on History, IAGA, 1994), pp. 159–167.
4.
The third choice of the faculty for the vacant Munich Professorship in Theoretical Physics was Arnold Sommerfeld (1868–1951), who accepted the position and made Munich a respected world-power in theoretical physics in the years 1905 to 1940.
5.
Russell McCormmach, Night Thoughts of a Classical Physicist (Harvard University Press, Cambridge, MA, 1982), p. 12.
6.
Heinrich Hertz, The Principles of Mechanics Presented in a New Form, translated by D. E. Jones and J. T. Walley (Macmillan, London, 1899). Reprint: Dover, New York, 1956 (with a new introduction by Robert S. Cohen). In his papers Lorentz frequently notes that matter and aether are for him only pictures (“Bilder”) of reality, in the sense that Hertz used the word in the Introduction to his Mechanics.
7.
On this see, e.g., Heinrich Hertz: Classical Physicist, Modern Philosopher, edited by Davis Baird, R. I. G. Hughes, and Alfred Nordmann (Boston Studies on the Philosophy of Science Vol. 198 [Kluwer Academic, Boston, 1998]). These criticisms of Hertz’s Mechanics by four famous physicists may be found in Joseph F. Mulligan, “The Reception of Heinrich Hertz’s Principles of Mechanics by His Contemporaries,” on pp. 173–181 of this book.
8.
Emil
Wiechert
, “Zwei Mittel zur Erleicterung der Beobachtung electrodynamischer Wellen
,” Ann. Phys. (Leipzig)
40
, 640
–641
(1890
).9.
Emil
Wiechert
, “Experimentalles über die Kathodenstrahlen,” Report delivered to the Phys. -Ökon. Gesellschaft zu Königsberg on 7 January 1897); reprinted in
Schriften der Phys. -Ökon. Gesellschaft zu Königsberg
38
, 3
–16
(1897
);quote is on p. 10. It is worth noting that Wiechert’s research was supported by a grant of 800 M from the Göttinger Gesellschaft der Wissenschaften. On this see Wilfried Schröder, “Zur Rolle der Gesellschaft der Wissenschaften bei der Entwicklung der Physik in Göttingen (1880–1930),” Gött. Nachr. (Math. Phys. Klasse) 85–99, 1985 on p. 89.
10.
Abraham Pais, Inward Bound (Oxford U.P., New York, 1986), p. 82.
11.
E. Wiechert (Ref. 9), pp. 14–16.
12.
Philip Stehle, Order, Chaos, Order (Oxford U.P., New York, 1994), pp. 78–80. [I have relied on Stehle’s helpful account of Wiechert’s work on cathode rays, and am grateful to Professor Stehle and to the Oxford University Press for permission to use the diagram from Stehle’s book as my Fig. 2.]
13.
E.
Wiechert
, “Ergebniss einer Messung der Geschwindigkeit der Kathodenstrahlen,”
Verhandlung der Gesellschaft Deutscher Naturforscher und Aerzte (1897, Vol. 2, first half), pp. 50–52. The later work of Wiechert on the electron is contained in one of his best experimental papers, “Experimentelle Untersuchungen über die Geschwindigkeit und die magnetische Ablenkbarkeit der Kathodenstrahlen,” Ann. Phys. (Leipzig)
69
, 739
–766
(1899
). [The first four pages of this paper reveal that Wiechert possessed all the necessary qualities to have been a truly great experimental physicist.]14.
See A. Pais (Ref. 10), p. 86. Wiechert never attempted to measure the charge on the electron directly. Other historians of science who have concluded that 1899 is the better date for the full discovery of the electron include: Barbara Turpin, “The Discovery of the Electron: the Evolution of a Scientific Concept. 1800–1899,” Ph.D. dissertation, University of Notre Dame, 1980 (unpublished);
James G. O’Hara, “George Johnstone Stoney and the Conceptual Discovery of the Electron,” Royal Dublin Society Stoney Symposium, 1991 (unpublished), pp. 5–28, on p. 25;
and Per F. Dahl, Flash of the Cathode Rays: A History of J. J. Thomson’s Electron (IOP, Bristol, Philadelphia, 1997). Dahl gives a particularly good account of Wiechert’s contributions on pp. 151–158 of his book.
15.
E. Wiechert, “Grundlagen der Elektrodynamik,” Festschrift zur Feier der Enthüllung des Gauss-Weber-Denkmals in Göttingen (Teubner-Verlag, Leipzig, 1899), pp. 3–109.
16.
Letter of Hendrik Lorentz to Emil Wiechert, 28 November 1899; in
Wilfried
Schröder
, “Hendrik Antoon Lorentz und Emil Wiechert
,” Archive for History of Exact Sciences
30
, 167
–187
(1984
); on p. 171.17.
E. Wiechert (Ref. 1), pp. 45–48.
18.
E.
Wiechert
, “Elektrodynamische Elementargesetze
,” Ann. Phys. (Leipzig)
4
, 667
–689
(1901
).19.
Richard P.
Feynman
, “Space-Time Approach to Quantum Electrodynamics
,” Phys. Rev.
76
, 769
–774
(1949
);reprinted in Henry A. Boorse and Lloyd Motz, The World of the Atom (Basic, New York, 1966), Vol. 2, pp. 1570–1581; quote on p. 1573.
20.
For an interesting example of the use of retarded potentials to calculate the radiation reaction from retarded fields, see Wolfgang K. H. Panofsky and Melba Phillips, Classical Electricity and Magnetism (Addision–Wesley, Reading, MA, 1962), pp. 387–389.
21.
Arnold Sommerfeld, Elektrodynamik (Akademische Verlagsgesellschaft Geest und Portig, Leipzig, 1954), footnote 2 on pp. 242–43. [The article of Wiechert that Sommerfeld refers to is the one cited in Ref. 1 above.]
22.
Wiechert (Ref. 1, p. 17) contains the following sentence in bold-face type: “Die Elektricität erscheint atomistisch gebaut, gerade so wie die Materie.” [“Electricity seems to be constructed of atoms, just as matter is.” This was written in 1896, before the existence of the electron as a separate particle was recognized.] A fuller expression of the same idea may be found in E. Wiechert, “Maxwell’s Theorie der Electrodynamik,” Naturwiss. Rundschau 11, 597–600 (21 November 1896);
on p. 599 Wiechert writes: “Die Elektricität scheint hiernach—wie es Helmholtz formulierte [1881]—atomistisch gebaut, gerade so wie die Materie. Wie von materiellen Atomen, so können wir auch von elektrischen Atomen reden.”
23.
E.
Wiechert
, “Über die Grundlagen der Electrodynamik
,” Ann. Phys. (Leipzig)
59
, 283
–323
(1896
).For the impact of this paper on the development of a new electromagnetic foundation for all physics, see Christa Jungnickel and Russell McCormmach, The Intellectual Mastery of Nature (University of Chicago Press, Chicago, 1986), Vol. 2, pp. 236–242.
24.
Reference 15, pp. 100–101.
25.
Reference 15, p. 108.
26.
Albert
Einstein
, “Zur Elektrodynamik bewegter Körper
,” Ann. Phys. (Leipzig)
17
, 891
–921
(1905
). Translated in Einstein’s Miraculous Year, edited by John Stachel (Princeton U.P., Princeton, NJ, 1998), pp. 123–160.27.
Wilfried
Schröder
, “Albert Einstein in seinen Beziehungen zu Mitgliedern der Gesellschaft des Wissenschaften in Göttingen
,” Arch. Hist. Exact Sci.
39
(2
), 157
–176
(1988
).Wilfried
Schröder
, On page 160 Schröder quotes this distinction from Wiechert’s manuscript notes for the course. See also Wilfried Schröder, “Ein Beitrag zur frühen Diskussion um den Aether und die Einsteinsche Relativitätstheorie
,” Ann. Phys. (Leipzig)
47
(7
), 475
–489
(1990
). This contains some very interesting letter exchanges in the years 1905 to 1925 between Wiechert, Lorentz, and Einstein.28.
W. Schröder (Ref. 27), p. 166.
29.
E.
Wiechert
, “Die Bedeuting des Weltäthers
,” Schrift d. Königsberg Phys. -Ökonom. Gesells.
35
, 4
–11
(1895
); on p. 11.30.
On this see David Lindley, The End of Physics: The Myth of a Unified Theory (Basic, New York, 1993), especially pp. 252–255. Stephen Hawking expresses Wiechert’s “infinite in all directions” idea in more technical terms: “The boundary condition of the universe is that it has no boundary”;
in S. Hawking, A Brief History of Time (Bantam, New York, 1988), 10th Anniversary edition, p. 141.
31.
For the full quotation see E. Wiechert (Ref. 1), p. 3.
32.
This very abbreviated summary of Wiechert’s contributions to geophysics and seismology is based on G. H. Angenheister’s article cited in Ref. 3; and on
Wilfried
Schröder
, “Emil Wiechert und seine Bedeutung für die Entwicklung der Geophysik zur exakten Wissenschaft
,” Arch. Hist. Exact Sci.
27
, 369
–389
(1982
). [G. H. Angenheister was a student of Wiechert who spent many years in charge of the Geophysical Institute in Samoa, a group of islands in the South Pacific, east–northeast of Fiji, in which location Wiechert had established a Geophysical Institute to assist in the observation and location of earthquakes. This Institute was affiliated with Wiechert’s Geophysical Institute in Göttingen. After Wiechert’s death Angenheister took his place as Director of the Göttingen Institute.]33.
Stephen G.
Brush
, “Discovery of the Earth’s Core
,” Am. J. Phys.
48
, 705
–724
(1980
).See also E. Wiechert, “Our Present Knowledge of the Earth,” Smithsonian Institution Annual Report, 1908, pp. 431–449. (At that time the Smithsonian translated important scientific articles in other languages and published them in its Annual Report.)
34.
Keith E. Bullen, “Emil Wiechert,” DSB, Vol. 14, pp. 327–328.
Also there is not even an entry for Wiechert in Armin Hermann, Lexikon Geschichte der Physik A–Z (Aulis Verlag Deubner, Köln, 1987).
35.
John L. Heilbron, “A History of the Problem of Atomic Structure from the Discovery of the Electron to the Beginning of Quantum Mechanics,” Ph.D. dissertation, University of California, Berkeley, 1964, pp. 27–49.
For Heilbron’s comments, see especially pp. 33–34 and also pp. 95–98.
36.
Wilfried
Schröder
, “Arnold Sommerfeld und Emil Wiechert
,” Arch. Hist. Exact Sci.
31
, 77
–93
(1985
). This paper contains many letters exchanged between Wiechert and Sommerfeld in the period 1898 to 1900. They contain little of scientific interest, however, since these letters primarily discuss arrangements for meetings to discuss their mutual interests in physics and geophysics, and matters related to their role as editors of Felix Klein’s Encyclopedia of Mathematical Sciences.37.
See
Emil
Wiechert
, “Bemerkungen über Bewegung der Elektronen bei Überlichtgeschwindigkeit
,” Göttingen Nachrichten
75
–82
(1905
);Arnold
Sommerfeld
, “Zur Elektronentheorie. III. Über Lichtgeschwindigkeits und Überlichtgeschwindigkeits—Elektronen
,” ibid 201–235 (1905). 38.
Arnold Sommerfeld, Autobiographische Skizze (1940), in his Gesammelte Schriften (Vieweg, Braunschweig, 1968), Vol. IV, p. 674.
39.
Hendrik A. Lorentz, The Theory of Electrons (Teubner, Leipzig, 1909);
American reprint of latest edition: (Dover, New York, 1952), p. 198, footnote 1. For Lorentz’s comments on Voigt’s priority see Abraham Pais, Subtle is the Lord (Oxford U.P., New York, 1982), pp. 121–122.
40.
W. Schröder, Ref. 16.
41.
Reference 16, p. 177.
42.
Same letter quoted in Ref. 41.
43.
Nobel Lectures in Physics, 1901–1921 (Elsevier, New York, 1967), p. 22. Despite Lorentz’s lumping together of the work of Wiechert and Larmor, these two disagreed strongly about the nature of the aether. Larmor maintained that the aether had mechanical properties and hence must be understood by using mechanical models; Wiechert held that a purely electromagnetic aether was the basis of all physics including mechanics.
44.
E. Wiechert, Ref. 13.
45.
E. Wiechert, Ref. 37.
46.
E.
Wiechert
, “Die Gravitation als elektrodynamische Erscheinung
,” Ann. Phys. (Leipzig)
63
, 301
–308
(1920
).47.
E.
Wiechert
, Phys. Z.
12
, 737
–758
(1911
). This article was severely criticized by the German Physicist Max von Laue, on pp. 118–120 and by the British physicist Norman Campbell, on pp. 120–128 of Vol. 13 (1912) of the same journal.See also
Norman
Campbell
, “The Aether
,” Philos. Mag.
19
, 181
–191
(1910
).48.
E.
Wiechert
, “Der Äther in Weltbild der Physik
,” Gött. Nachr.
29
–70
(1921
). An English translation of pp. 57–62 of this paper may be found in Ernst Mach—A Deeper Look, edited by John Blackmore (Kluwer Academic, Dordrecht, 1992), pp. 165–171.49.
“Nomination of Emil Wiechert as a Corresponding Member of the Berlin Academy of Sciences, December 1911,” in Physiker über Physiker, edited by Christa Kirsten and Hans-Günther Körber (Akademie-Verlag, Berlin, 1975), pp. 197–198. The reference here is to the paper cited in Ref. 47 above.
50.
On the history of the idea of the infinity of the universe and its philosophical (and theological) implications, see Alexandre Koyré, From the Closed World to the Infinite Universe (The Johns Hopkins U.P., Baltimore, London, 1957), paperback edition. Koyré points out that “The conception of the infinity of the universe is, of course, a purely metaphysical doctrine that may well—as it did—form the basis of empirical science; it can never be based on empiricism.” (p. 58)
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