The length of a rehearsal

Rachmaninoff completed his Third Piano Concerto at his summer estate at Ivanovka in September-October 1909.  He then toured America, learning the piano part on a dumb piano aboard the ship.  The work was first performed in New York under Walter Damrosch in November 1909.  In January 1910, Gustav Mahler conducted the third New York performance. Rachmaninoff recalled:

He touched my composer’s heart straight away by devoting himself to my concerto until the accompaniment, which is rather complicated, had been practised to the point of perfection…

The rehearsal began at 10 o’clock.  I was able to join at 11 and arrived in good time, but we did not begin work until 12, when there was only half an hour left, during which I did my utmost to play through a composition which usually lasts 36 minutes. We played and we played.  Half an hour was long past, but Mahler did not pay the slightest attention to this fact… Forty-five minutes later Mahler announced, “Now we will repeat the first movement.”  My heart froze … I expected a dreadful row, or at least a heated protest from the orchestra … but I did not notice a single sign of displeasure.  The musicians played the first movement with a keen or perhaps even closer application than the previous time.  I went up to the conductor’s desk, and together we examined the score.  The musicians in the back seat began quietly to pack up their instruments and to disappear.  Mahler blew up.

“What is the meaning of this?” The concertmaster: “It is after half past one, Maestro.”

“That makes no difference.  As long as I am sitting, no musician has the right to get up!”