Sing it with me...

In 1878, on this date, the song Eight Hours was published, which remained the most popular labour song until it's popularity was overshadowed by Solidarity Forever

From the page linked above:

"In 1850 the average work week was 70 hours, in 1900 the average work week was 60 hours and in 1920 the average work week was 50 hours. In the 1840s unions began working for a 10 hour day."

Here's a webpage about the Eight-Hour Movement

(Of course, the employer was always only concerned about the worker's welfare and health...)