Answer:
On 19 May 1869, President Ulysses S. Grant issued a National Eight-Hour Law Proclamation. The backlash from the Haymarket affair set the movement for a shorter workday back for decades. With the Great Depression's severe unemployment, the labour movement revived the idea of reducing work hours and pushed for passage of the Fair Labor Standards Act, establishing an eight-hour day and forty-hour week. The Haymarket Riot (also known as the “Haymarket Incident” and “Haymarket Affair”) occurred on May 4, 1886, when a labour protest rally near Chicago's Haymarket Square turned into a riot after someone threw a bomb at police. At least eight people died as a result of the violence that day. The Knights of Labor, a powerful advocate for the eight-hour day in the 1870s and early 1880s, proved more effective. Organized in 1869, by 1886 the Knights of Labor counted 700,000 labourers, shopkeepers, and farmers among its members. Henry Ford helped change our work hours. At the time of the Industrial Revolution, eight-hour work days were not heard of as the factories needed to be tended to all the time.