fomat68, фамилия вашей прабабушки скорее всего правильно писалась— Бослер/Босслер/ Bossler.
Для начала посмотрите здесь:
http://lists.memo.ru/index2.htm. А также Босслер, с двумя— сс.
Её предки проживали в колониях: или Цюрих или Шафгаузен.
А это скорее всего ее первый предок, который прибыл в Россию/ Поволжье:
Bosler
Spelling Variations:
Bosler
Settled in the Following Colonies:
Schaffhausen
Discussion & Documentation:
Leonhard Bosler, a tailor (Schneider), and his wife Anna arrived from Lübeck at the port of Oranienbaum on 12 September 1766 aboard an English frigate under the command of Skipper Adam Beerfeier.
Leonhard Bosler is recorded on an appendix to the 1767 census of Boisroux (No. 12) along with his new wife Maria. Leonhard Bosler is recorded on the 1798 census of Schaffhausen in Household No. Sh42.
Both the Oranienbaum passenger list and the 1767 census record that Leonhard Bosler came from the German region of Nürnberg.
Sources:
- Mai, Brent Alan. 1798 Census of the German Colonies along the Volga: Economy, Population, and Agriculture (Lincoln, NE: American Historical Society of Germans from Russia, 1999): Sh42.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 1 (Göttingen: Göttinger Arbeitskreis, 1999): 164.
- Pleve, Igor. Lists of Colonists to Russia in 1766: Reports by Ivan Kulberg (Saratov: Saratov State Technical University, 2010): #4607.
https://volga.domains.unf.edu/surnames/bosler.