Hi,
You're cheating a bit, Mike !
This wasn't "c'4~ c'8." instead of "a4~ a8." in the lower voice.
It's even more tight !
Here is the example in context (Breitkopf und Härtel 1878) :
The last two systems of the second page.
You can also notice a similar case on the last PDF page. Last system, measure 2, third beat, upper staff.
I also have many other cases of "three-voices-tight-situations" in more recent editions, especially Bärenreiter.
I saw one day a XIXth century book with VERY tight music everywhere. Something like 6 voices Preludes and Fuges everywhere. Of course, beautifully engraved. If I could find it again... This thing is really the bible of beam collisions !
Now I have to go away for the WE.
Regards,
Bertrand