What is the original source for Abel's quote about Gauss:"He is like the fox, who effaces his tracks in the sand with his tail"?

Question

According to the editor of the German version of Ian Stewart's "The Problems of Mathematics", on page 226 of the biography of Gauß authored by Erich Worbs (C. F. Gauß: Ein Lebensbild. Koehler & Amelang, Leipzig, 1955) we can find the following comment:

... schreibt Abel in seinen Reisebriefen über Gauß: „Er macht es wie der Fuchs, der seine Spuren im Sande mit dem Schwanz auslöscht.“ (Abel wrote in his letters about Gauss:"He is like the fox, who effaces his tracks in the sand with his tail").

I wonder if it is actually known whom was the aforementioned letter addressed to or, failing that, if you know of a website wherein one can find a retrodigitized copy of Abel's Briefwechsel.

Please, let me thank you in advance for your knowledgeable replies.

UPDATE: I have spotted 5 letters from Abel to Prof. Christopher Hansteen in this document (Michael E2: thanks a bunch for the tip-off!) If I am correct, in none of those letters one can find the famed „Er macht es wie der Fuchs, der seine Spuren im Sande mit dem Schwanz auslöscht“ quote. Nevertheless, almost at the end of the preantepenultimate paragraph of the fourth letter in the aforecited document (written on December 5, 1825), we do read this:

Hos Crelle var før ogsaa een Gang om Ugen en Samling af Mathematike men han var nødt til at ophøre dermed da der var een ved Navn Ohm, som ingen kunde komme ud af det med formedelst hans skrækkelige Arrogance. Det er tilforladelig tungt at en enkelt Mand saaledes lægger Hindringer i Veien for Videnskabelighed. Det er over al Maade hvor de unge Mathematikere her i Berlin og som jeg hører over alt i Tyksland ligesom forguder Gauss. Han er for dem Indbegrebet af al mathematisk Fortræffelighed, men lad være at han vist nok er et stort Genie saa er det ligesaa vist at han er [!] et slet Foredrag. Crelle siger at alt hvad Gauss skriver er Gräuel, da det er saa dunkelt at det næsten ikke er mueligt at forstaae det.

I guess this means that C. A. Bjerknes's account isn't altogether inaccurate. Besides, according to the author of Niels Henrik Abel and his times: called too soon by flames afar, Prof. Hansteen published some letters by Abel in the Illustreret Nyhedsblad in 1862: surfing the official website of the Abel Prize, we learn that the exact reference to these letters in the said journal(?) is:

Ch. Hansteen. Niels Henrik Abel, Illustreret Nyhedsblad 11 (1862), 9-10, 37-38, 41-42 (2nd and 9th of March).

It seems to me that, at one point of time, the archives of the Illustreret Nyhedsblad were available online here:

http://goo.gl/GboE9v

Have they been taken down or do I need to add something to my web browser in order for the corresponding files to be displayed correctly?

Answer 1

Bjerknes cites a letter from Abel to Christopher Hansteen, a fellow professor of Bjerknes at Christiania/Oslo, who had put up and mentored Abel in the beginning of his career.

Den omgangskreds af aeldre, hvortil han hörte, var vel selvfölgelig heller ikke sa enthusiastisk Gauss-stemt som Berlinerungsdommen. Sjelden er det derhos, at ikke den stigende ros og berommelse, idet den går over sine bredder, fremkalder modsigelser. Indenfor den Crelleske kreds blev derfor så naturligt en og anden gang også den anden side fremholdt; og det hedte da om Gauss: hans foredrag var slet; or at han "Er macht es wie der Fuchs, der wischt mit dem Schwanse seine Spurten im Sands aus". (1)

(1) Citat af Hansteen i anledning at den naevnte bemaerkning i brev fra Abel

-- C.A. Bjerknes, Niels Henrik Abel. En skildring af hans liv og videnskabelige virksomhed (Stockholm. 1880), p. 61

My Norwegian is completely dependent on Google Translate. Here is a 1885 revision by Bjerknes in French:

La société des personnes âgées, qu'il fréquentait, ne partageait pas, cela va sans dire, le gaussianisme enthousiaste de la jeunesse berlinoise. It est rare, en effet, que la renommée croissante d'un nom vanté, lorsqu'elle dépasse les bornes, n'attire pas la contradiction. Dans la société de Crelle, it était tout naturel qu'une fois ou l'autre on soutint la seconde opinion; et l'on disait que «sa manière d'exposer était mauvaise», ou encore qu'«it faisait comme le renard, qui efface avec sa queue les traces de ses pas sur le sable.»

-- C.A. Bjerknes, Niels-Henrik Abel: tableau de sa vie et son action scientifique (Paris, 1885), pp. 91-92

Roughly, it says: The elder mathematicians did not share in the enthusiasm for the "Gaussianism" of the younger generation in Berlin. Seldom does a name become vaunted without the opposite opinion also arising. So that in Crelle's society, it was quite natural that now and then someone would say about Gauss that his lectures were bad or "he makes [his mathematics] like a fox, wiping out the traces in the sand with his tail."

From this account it appears that the saying was something Abel reported, but perhaps did not make up himself.

Bjerknes goes on to say that Abel reports that Crelle says that everything Gauss writes is "abomination" ("Gräuel"), since "it is so obscure that it is almost impossible to understand it." (That is a friend-of-a-friend-of-a-friend-of-a-friend report, from Crelle to Abel to Hansteen to Bjerknes).

I'm not sure where the letters from Abel to Hansteen are. Some have been published, but I don't know if the one referred to by Bjerknes has been.

Answer 2

This is a supplement to the previous answer to the question, confirming what has been written above.

Illustreret Nyhedsblad, where prof. Chr. Hansteen in 1862 first published some letters from Abel, is available online from the National Library of Norway. The relevant letter is the one Abel wrote on December 5th, 1825, which is quoted above, and which can be found in issue No. 9, March 2nd, 1862. At the end of the comment on Gauss' obscureness, Hansteen has inserted a footnote:

En Tydsk Student sagde om ham i den Anledning: "er macht es wie der Fuchs, der wischt mit dem Schwanze seine Spuren im Sande aus".

So the quote is here attributed to an unnamed German student. When C. A. Bjerknes wrote his biography on Abel, he put together the material on Gauss from Abel's letter with the footnote from Hansteen, and in the French edition the reference to Hansteen was lost. The French text has then been retranslated to German, giving a slightly different wording from the original.

Hansteen had an extensive scientific correspondence, mostly on the subject of magnetism, and he had visited Gauss in 1839 to discuss his theories on the subject. It is not surprising that he was well acquainted with anecdotes about Gauss.