Adding machine, c.1910

S & N adding machine by Seidel & Naumann, Dresden, serial no. 2398, in fitted box with stylus and instructions. The Seidel and Naumann adding machines used chain drives and a stylus. The numbers to be added were pulled down to the base bar and then appeared in the result window. Pressing the lever A allowed the inputted figures to be checked before the machine reset, while pressing M allowed faster work as each figure reset when the stylus was removed. Subtraction was performed using the complementary columns at the sides.