Guest Post By: Richard Thomas Figure 1: s/n 2541201 Beginning in 1911 and continuing through 1914, the Illinois Watch Co. introduced their new 16s, Model 9, Nickel Bridge movement. Year IntroducedFirst Serial No.GradeJewelsAdjusted1911233703171023T, I, 6 Positions1913252600170517T1913252640170619T, I, 3Positions19132541331Sangamo Special21T, I, 6 PositionsT = Temperature; I...