This Dalton ten-key manual adding machine is from the late 1920’s or later since the glass sides are not present. There are two rows of white plastic number keys marked with digits in the sequence: [2 4 5 7 9] on top and [1 3 0 6 8] below. The black keys are function keys labeled: multiply, backspace, correction, release, subtotal, and total. Located on the right hand side is a hand crank. The machine is designed to print out nine-digit totals on a paper roll inserted into a paper tape dispenser and feed through a movable nine-inch carriage located just in front.
By the 1920's over 150 models of Dalton Adding Machines were designed. Its popularity arouse because of how easy it was to pick up its fast and simple ten-key design which required less hand motions, which meant less erroneous mistakes and more accurate calculations. It was so easy to pick up the workings of a Dalton that an advertisement exemplifies this with a single quote, “An inexperienced girl and a Dalton will replace two men who figure with pencil.”