Several people say the mathematician David Hilbert gave "Crêpe-de-Chine-Vorlesungen'' in the 1930s. The phrase means that the audience at the lectures included many somewhat wealthy people and specifically refers to the women's clothes. The phrase is rare on the internet today and seems to be only historical.
Can anyone tell me whether this use of "Crêpe de Chine" was a common slang in the 1920s and 1930s? Was it specifically academic slang?
To be clear, I know what the phrase means, and Michael Brenner and Detlev Claussen both explain it in quotes below.
I am asking whether it was popular slang, or academic slang, or really not common at all in Germany of the 1920s and 30s.
As to sources it is possible that all the references specifically to Hilbert trace back to Hel Braun's posthumously published autobiography Eine Frau und die Mathematik 1933–1940. Der Beginn einer wissenschaftlichen Laufbahn.
But also Michael Brenner's book The Renaissance of Jewish Culture in Weimar Germany says
Martin Buber helped to realize an important goal set by Rosenzweig: to attract not only schoolgirls but also the "crepe-de-chine" audience, the upper-middle class of the Frankfurt Westend."
And I find one passage written in the 1920s in Franz Rosenzweig: Der Mensch und Sein Werk: Briefe und Tagebücher p. 869:
wollte ich das Crepe-de-Chine-Publikum bei der Stange halten
Here is another suggestion that it may have been academic slang. German historian, Detlev Claussen, says in his book Theodor Adorno - One Last Genius:
[Frankfurt] university likewise developed the custom of what were known as crêpe-de-chine lectures. Dr. Wiesengrund’s inaugural lecture is supposed to have been one such occasion. It is said that the crème de la crème turned out to hear him.
He does not really say Frankfurt University coined the term, but Rosenzweig quoted above was in Frankfurt.
While Braun could conceivably have gotten the phrase from Rosenzweig (or Buber) it is not at all likely given her interests and the way she spent her time. If it originated with Rosenzweig it must have passed through a few hands before reaching her. And she uses it as if it were common coin, with no explanation at all of what it means.
I did find others but it is hard to relocate them now since naturally a search of "Crêpe de Chine" gets lots of irrelevant hits.