Watchmakers school BIEL open face silver pocket watch, Switzerland around 1930, heavy case, on the rear side relief of the 'Ludwig von Roll′schen Eisenwerke', two-piece construction enamel dial with Breguet- numerals, constant second at 6, blued Breguet-hands, cuvette with dedication engraving, gold plated lever movement marked 'Technicum Cantonal Bienne no. 738', 16 jewels, compensation-balance with Breguet- hairspring, diameter approx. 54 mm, bow later, condition 2