Am 1999-07-13 um 0:22 h hat Doug Ewell geschrieben:
> I found several instances of round s (end of syllable) followed by
> long s (start of next syllable), as Otto mentioned, but interestingly
> I also found the word "dessen" spelled with two long s's (de\u017f\u017fen).

I have omitted this detail from my recent contribution to keep it concise,
but now as you have asked for it, you get the whole story.

In contemporary German orthography (established in 1901 by a spelling
conference and propagated by Konrad Duden's notorious "Orthographisches
Wörterbuch" in 1902),
- double Long-S denotes a sharp (i. e. voiceless) S-sound (as both "c" and
  "ss" in "voiceless") after a short vowel;
- in rare cases (e. g. "bis" and "Bus") a single S is used instead;
- the voiceless S-sound after long vowels (including diphtongs) is normally
  denoted by an "Eszet" (=German Sharp-S, U+00DF, "ß");
- the voiced-S sound (as in "wise") is denoted by a single s: Long-S
  at the start, and Round-S at the end of syllables; at the end of words,
  the S becomes voiceless, this change is not reflected in the spelling
  (e.g. "Glas" and "Gläser" are pronounced with voiceless and voiced S,
  respectively);
- Long-S is also used in the Trigraph "sch" which denotes the sound
  usually spelled as "sh" in English (e.g. in "wishlist");
- Long-S is also used in the "st" and "sp" combinations where it denotes
  the "sh"-sound in the beginning, and the voicless S-sound at the end
  of a syllable (e.g. "Strudel" is pronounced as "Shtroodel", whilst
  "Gast" is pronounced as English "gust").

Of course,
- when the Long S is not used at all, a common s (U+0053) is used instead;
- dialects differ in details of the pronounciation; the above rules refer
  to the standardized pronounciation.

Before the recent spelling reform, there was an additional rule requesting
that double (long) S -- according to the above rules -- be replaced with
Eszet in certain contexts I will not explain here. This rule has been
dropped in the new orthography (effective from 1998-08-01).

> Otto, is [double Long-S] the typographical form that became ß (sharp s)?

No.

"ß" is derived most probably from a ligature of U+017F (Long-S) with U+001B7.
In early medeaval hand-writing, the latter denoted an S-like sound (I forget
which one); in German printing, e.g. "Teuerdank" by Kaiser Maximilian I
(1517), no ISBN given :-) and handwriting (I've seen specimens of the 18th
and 19th century), the U+001B7 glyph is used for the Z (pronounced as "TS",
in German); "ß" was then perceived as an S-Z ligature, hence its German
name "Eszet". (Btw., "Eszet" was also a chocolade brand from the Stängel &
Ziller Company at Stuttgart.)

Some, notably the typographer Jan Tschichold, think that "ß" is rather
derived from a ligature of Long-S and Round-S (U+017F and U+0053).

Best wishes,
   Otto Stolz