I spotted an old ledger designed to record a company’s payroll expenses while shopping in a secondhand store. A chart inside the front cover listed pay calculations based on different hourly wages. These calculations were also split into 15-minute increments. If a person earned $2.35 per hour, and he worked for 15 minutes, the chart showed that he would receive exactly 59 cents. If his workday lasted 8 hours, he would receive $18.80. Using this chart, a business owner could determine and record exactly what each employee had earned—not a penny less, not a penny more.