The story goes that bartenders at James Ritty’s Pony House Tavern were skimming money off the bar’s sales. Ritty, understandably aggravated, was returning from a trip to Europe when he noticed a dial on the bridge that counted the revolutions of the ship’s propellers. Intrigued, Ritty returned home to Dayton and proposed the idea for a calculating sales machine to his brother John, a mechanic. After developing a few prototypes that failed, the brothers developed a machine that replaced the numbers on the dial with dollars and cents. Pressing a key on the machine would add that dollar amount to the total day’s sales, displayed on the dial. There was no cash drawer at this point – just the running tally. Example of Ritty’s early design can be found at the Smithsonian National Museum of American History in Washington, D.C. or at Carillon Historical Park in Dayton, Ohio.