While vintage newspapers have brought to light concerts that had escaped the census, one must remain cautious and cross-reference such discoveries with other sources.
For example, the Frauenfreude-Mädchenglück, a Czech German-language periodical, in its January 23, 1929 issue, announced a concert by the Vienna Philharmonic at Prague's Lucerna Hall on Monday February 18, with Furtwängler conducting. This visit would have followed the series of fifth subscription concerts at the Musikverein, on the 16th and 17th. It would have included the second half of the program — Mahler's First Symphony — while the first half would have featured Beethoven's Symphony No. 1 and Strauss's Death and Transfiguration. How can you possibly believe that this concert is not actually taking place when you read the last sentence of the concert announcement: tickets are now on sale!
As this Prague escapade is missing from the list of concerts that can be consulted on the Wiener Philharmoniker website, we contacted the Wiener Philharmoniker Archives, and the answer came quickly: although Furtwängler mentions this series of concerts and the Prague concert in a letter dated January 8, this concert does not appear on any of their lists, nor in the printed programs.
The concert was therefore cancelled, but the reason for this remains unknown.