In the USA, in Illinois you have a law for 8 hours (with loopholes) at 1867! Chicago saw that year a whole week of workers strike trying to get that. In the next 20 years, lots of cities and professions got the 8 hours. And in 1886, see what happened in May Day and in the following Haymarket Riot.
The real reason for the 8 hours is the anarchist push for a more human treatment of workers'life. Those working class anarchist masses in Europe went to North and South America in numbers, and started there a very strong push for workers organizations, shaping some countries cultural shape up to this day. THAT is the real push for the 8 hours, those are the real reasons, in a history that most of the world knows but in the USA is still neglected and hidden. So, seen an article about the genius of Ford for the 8 hours in 1914 is sad. What he did was doubling the wages, and got an improvement in productivity. The 8 hours has a rich, hard fought and tragic history that is more than 50 years older, and which was usually drowned in blood by those same industrial tycoons.