I am engaving a complete edition of the Haydn String Quartets from the 1803 Pleyel "Bonaparte" edition, to provide players with access to this particular edition, which does not suffer much from 19c bowdlerisation at the hands of editors.
Op. 17 No. 1, cello part, in the Trio has the directive 'T.S.' as shown here. I have never encountered this before. Does anybody know what this may mean?
I do not believe this could be 'Tasto Solo' as it is well agreed by scholars that the quartets by this time did not use continuo, certainly not in Austria or Vienna, and there are no figured bass markings in this edition [Although there does exist a score of this opus with a figured continuo basso, but this can be ignored for many reasons.]