Calculator, ca. 1900
This calculator adding machine was used in the early 1900s in offices and mills in the Livermore Falls area to add columns of figures, calculate amounts by adding, subtracting, multiplying, and dividing to reach the total requested. A stylus, or pencil-like tool, was used to move or rotate the dials. The two right hand dials denoted cents or percentages while the dials running to the left showed ones, tens, hundreds, thousands, and tens of thousands. This was the only calculator at the time that could be moved backwards to correct errors after the number had been registered and the total recorded. All other machines had to start the operation all over again.