The plan to prepare a complete online edition of Ernst Mach’s correspondence

By Prof. Dr. Klaus Hentschel (director of the section for History of Science & Technology [GNT], History Dept., University of Stuttgart, Germany)

A complete edition of the correspondence of the world-famous physicist, physiologist, philosopher, and pioneer historian of science, Ernst Mach (1838–1916) is planned by Klaus Hentschel in Stuttgart. Ernst Mach’s life is intimately linked with three countries (the Czech Republic as the region of his birth and of his professorship in Prague from 1867-1895), Austria (studies at the University of Vienna, professorship in Graz 1864-1866, and professorship in Vienna (Prof. f. Philosophie, insb. Geschichte und Theorie der induktiven Wissenschaften, 1895-1901) and Germany (his final years in Vatterstetten near Munich in the home of his son Ludwig). The network of his correspondents covers most countries of Europe, North- and South-America, and India. Therefore this is clearly an international and highly interdisciplinary project. We hope to obtain funding for this project from the German Academy Union – Prof. Dr. Klaus Hentschel (director of the section for history of science & technology, History Dept., Univ. of Stuttgart and member of section 23 of the Nationale Akademie der Wissenschaften Leopoldina), prepared and submitted a formal application to the Akademie-Union for a 12 year long-term project which – if funded – would begin in January 2019. Anyone interested in taking a serious part in this project is cordially invited to contact Klaus Hentschel at


What selected editions are there already?

The most extensive published anthologies are the following five:

Joachim Thiele: Wissenschaftliche Kommunikation, Die Korrespondenz Ernst Machs, Kastellaun: Henn, 1978 (based on various articles by Thiele in journals on single correspondents, sorted by groups of correspondents, often only including the letters sent to Mach, with detailed commentary and annotation);

John T. Blackmore & K. Hentschel (eds.): Ernst Mach als Außenseiter, Machs Briefwechsel über Philosophie und Relativitätstheorie mit Persönlichkeiten seiner Zeit, Auszug aus dem letzten Notizbuch (Faksimile) von Ernst Mach, Vienna, Braumüller 1985 (sorted chronologically, concisely annotated);

Rudolf Haller & Friedrich Stadler (eds.): Ernst Mach - Werk und Wirkung, Vienna: Hölder, Pichler & Tempsky, 1988 (w. letters to and from Heinrich & Theodor Gomperz, Friedrich Adler & Fritz Mauthner, sparingly annotated);

Dieter Hoffmann & Hubert Laitko (eds.) Ernst Mach. Studien und Dokumente zu Leben und Werk. Berlin: Akademie-Verlag 1991 (G. Fechner, W.F. Behn, F. Zarncke, W. Ostwald, R.Lowie, E. Haeckel, H. Driesch, V.Schumann, O. Wiener, all sparingly annotated);

John T. Blackmore, Ryoichi Itagaki, Setsuko Tanaka (eds.): Ernst Mach’s Vienna 1895–1930. Dordrecht: Kluwer Academic Publishers, 2001 (specific letters to and from, e.g., Friedrich Adler, Philipp Frank, Edmund Husserl, Wilhelm Jerusalem, Wilhelm Ostwald in Engl. transl.).

Ernst Mach’s correspondence with Franz Brentano is edited in Roderich M. Chrisholm & Johann C. Marek (eds.) Franz Brentano – Über Ernst Machs “Erkenntnis und Irrtum” aus dem Nachlaß herausgegeben und eingeleitet, Amsterdam: Rodopi 1988, pp.201-228.

Ernst Mach’s letters to Alexius Meinong are published in Philosophenbriefe. Aus der wissenschaftlichen Korrespondenz von Alexius Meinong, Graz: Akad. Druck- u. Verlagsanstalt 1965, ed. By Rudolf Kindinger, pp. 89-93.

Furthermore, there exist dozens of articles in German, Austrian, American and British, Czech and Japanese research journals with individual letters to or from Ernst Mach, in some rare cases also covering both sides of the correspondences, such as, e.g., some of Joachim Thiele’s articles collected in 1978, or

Klaus Hentschel: Die Korrespondenz Duhem-Mach: Zur ‚Modellbeladenheit‘ von Wissenschaftsgeschichte. In: Annals of Science 45 (1988): pp. 73–91 (with all preserved, complete letters between Pierre Duhem and Ernst Mach);

Selections from the extensive correspondence of Ernst Mach with the ballistics expert Peter Salcher, who worked at the k.k. Marine Academy in Fiume, today Rijeka, was published by Günter Salcher and Gerhard Pohl in the Mitteilungen der Österreichischen Gesellschaft für Wissenschaftsgeschichte 21 (2001), pp. 25-51, with excerpts and a few facsimiles also in Plus Lucis 2(2002-1/2003, pp. 22-26; cf. futhermore Bernard Frankovic & Gerhard Pohl (Hrsg.) Peter Salcher-Ernst Mach – A Successful Teamwork, Zagreb: Hrvatska akademija znanosti i umjetnosti 2011.

Six letters by Ernst Mach to the physiologist Alexander Rollett (1834–1903), written betzween 1874 and 1897, are published online in the Alexander Rollett online correspondence edition.

Both sides of Mach’s correspondence with the language philosopher and writer Fritz Mauthner (1849–1923) from 1889 until 1915 have been published online;  Mauthner’s letters to Mach are also published in Thiele 1978.

All these existing publications are only pickings of  individual letters or correspondents; they are often poorly if at all annotated and often not easily available in research libraries all over the world. Therefore:

We need easy and unconstrained access to the complete letters to and from Ernst Mach in their chronological order, and an online edition can offer this.


How many letters are there altogether? And where are they kept?

My current estimate for the complete correspondence of all letters to and from Ernst Mach is between 4,000 and 5,000 letters.

Most of the letters addressed to Mach (preserved in his estate after his death in Vaterstetten near Munich in 1916), formerly kept in the Ernst Mach Institut für Kurzzeitdynamik der Fraunhofergesellschaft in Freiburg/Breisgau, are now preserved at the Deutsche Museum in Munich: cf. the detailed published finding aid of these 2,729 letters plus other materials: Wilhelm Füßl & Margrit Prussat: Der wissenschaftliche Nachlaß von Ernst Mach (1838-1916) (Veröffentlichungen aus dem Archiv des Deutschen Museums, vol. 4). Munich 2001,  and  An amended online finding aid of these holdings which also include Mach’s notebooks, Schlieren photographs of projectiles and other material, and links to facsimiles will eventually be released by the Archives of the Deutsche Museum within the context of their Museum online initiative.

Excerpts from Mach’s correspondence with his son Ludwig Mach and other materials from the former Mach family archives which is now also housed at the Deutsches Museum München are quoted and facsimilzed in the catalogue Licht und Schatten, edited by Wilhelm Füssl & Johannes-Geert Hagmann, Munich, Deutsches Museum, 2016.

A smaller partial estate (c. 36 letters), based on collections by Ernst Mach’s son Ludwig has been transferred in 1998 to the Staats- und Universitätsbibliothek Göttingen and is kept there under call no. Cod. Ms. E. Mach 1-36. It contains exp. Letters to and from Ernst Mach’s son Ludwig Mach.

All of Mach’s correspondence with the German National Academy of Sciences Leopoldina, esp. concerning his own election to this academy in 1873 and concerning the election of other academics to the Leopoldina later on,  are kept in the archives of the Deutsche Akademie der Naturforscher Leopoldina and currently under study in the context of an ongoing BA-thesis of the Stuttgart GNT student Maja Lichman.

Dozens of other letters by Ernst Mach and drafts of letters to him are kept in Berlin, Leipzig, Vienna, Prague, Fiume, Zagreb etc.

Mach’s own letters are dispersed throughout Europe, North and South America, India, Australia etc. in hundreds of archives hosting estates of his contacts. Klaus Hentschel’s student Sten Otte in Stuttgart has prepared a geo-referenced map of 2579 letters (mostly written to Mach), kept in the Archives of the Deutsches Museum in Munich, Germany. The map can be inspected in closer detail and various levels of spatial resolution online at    (the image takes quite a while to build up – keep patient !)

A low resolution selection (showing North America, Europa and Russia) is shown in the following image (© GNT 2017).

Below the map you also see a time-scale and the temporal distribution of the letters kept in Munich; online you can animate this and trace the correspondence over time chronologically.




















A listing of all known letters to and from Mach is in preparation at the Univ. of Stuttgart

Currently, we are preparing a survey list (a “Konvolutenliste”, i.e., not yet a listing of individual letters, but only of groups of letters with their temporal range and current location), which already includes findings of Mach correspondence in the following towns worldwide: in Austria: Graz, Vienna; in Denmark: Copenhagen; in England: Cambridge, Oxford, Corner Croft, Wilmslow, Cheshire; in France: Paris; in Germany: Aschaffenburg, Berlin, Bremen, Dortmund, Göttingen, Jena, Konstanz, Leipzig, Munich and Tübingen; in the USA: Berkeley and Claremont, California; Washington, D.C.; New York City; Carbondale, Illinois; Amherst and Cambridge, Mass ; in the Czech Republic: Prague; in Croatia: Fiume (today Rijeka) and Zagreb, in Poland: Krakau/Cracowia; in Sweden: Uppsala; in Switzerland: Geneva and Zurich; in Israel: Jerusalem.

This listing is based on the decades-long research of:

John Blackmore (formerly Vienna and Tokyo, Japan, now Bethesda, Maryland, USA)

Joachim Thiele (1931-1980) in Hamburg, Germany, until 1980

Klaus Hentschel (since 1981)

and publications of Mach scholars worldwide, esp. Dieter Hoffmann, Ryoichi Itagaki, W.G. Pohl, Friedrich Stadler, Setsuko Tanaka, Emilie Tesínská, Joachim Thiele, Gereon Wolters; etc. (in alphabetical order).

If you are interested to contribute to this project you are kindly asked to send an email with your full name and title, institute affiliation and brief comments on your possible contributions to this project to:

Source of the above: (first posted in the internet on June 10, 2016, last change May 24, 2017)