There have been several postings on this subject recently. The latest was from Alan Rossing <alan@juno.com> on 15 Nov 1999. My own conclusion is that in the Germanic areas of Switzerland and Württemberg it represented the sound "eye" and could be used interchangeably in spelling with either the letters "i" or "ei" when they represent that sound. Some of the examples I have encountered: Weiss <-> Wÿss <-> Wÿß (Brienz, Canton Bern) Wiler <-> Wÿler (For Brienzwiler) Thöni <-> Thönÿ (Brienz)** bei <-> bÿ (A surprise from the church records of Beilstein, Oberamt Marbach, Württemberg) ** The ending "i" of a surname was frequently written with a descending tail, also This use of ÿ contrasts with the apparent use of "ÿ" in lower Germany and the Netherlands (discussed in the "German-Life" discussion group by Siske Hoogerhuis) to replace the "ee" sound indicated by the letters "ij". Lyle G. Hartman Landenberg, Pennsylvania