James Ritty built a cash register to make theft visible

James Ritty opened a saloon in Dayton, Ohio in 1871 and became convinced his bartenders were pocketing part of what customers paid for drinks and cigars, since nothing forced a sale to leave a trace. He had no way to prove it: a bartender's word about the day's takings was the only record, and confronting staff on suspicion alone was both legally and practically useless without evidence. The standard response of the era was tighter supervision or firing on suspicion, which caught almost nothing and cost trust either way.

In 1878, on a steamship crossing to Europe, Ritty was shown the engine room's mechanical counter, which ticked over every rotation of the propeller shaft regardless of what the crew above deck did or said about it. The counter didn't rely on anyone's honesty to produce a true number, and Ritty spent the rest of the crossing turning that same idea over for the till of a saloon he'd left in his bartenders' hands.

Built a register that automatically recorded and totaled every sale, making skipped recordings conspicuous, so theft became visibly deviant rather than undetectable.

Without a register, the bartender's word was the only record, so theft was invisible and unprovable.

A register that totals every sale on a visible dial removes discretion, making skipping the recording step conspicuous.

Honest use of the register is simply how a sale is completed, so most employees use it without needing trust.

The device converts the problem from proving theft after the fact to noticing deviation from expected behavior.

To stop theft, don't catch the thief; build a system that records every transaction automatically, making honesty the path of least resistance.

Ritty and his brother struggled to manufacture and sell the device profitably and sold their patent and business interests to investors in 1881; under new ownership it was renamed National Cash Register in 1884 and became the dominant firm in a category that scarcely existed before Ritty's saloon problem created it.