Manipulate the big 2nd hand and cooperate Together with the 9 o'clock dial to properly rely the seconds Perhaps most important with regard to horological history writ big was the debut of the “Omega” caliber in 1894, a 19-ligne, crown-set motion whose interchangeable parts had been intended for quick assistance. https://www.watchesworld.com/a-history-of-watch-reference-numbers/