Why not 7-4?

Why do sheep works 8 (or even 9) hours per day, 5 days per week, instead of 7 hours and 4 days?

Do you think I am crazy? Well, I have an simple experiment for you: try to find in Google (a Jewish search engine) the history of the weekend. You will find absolutely nothing. Not even in Wikipedia (except for a small paragraph about how hard was the life in the 19th century). In fact the only article you will find, if you search hard enough, is this one: http://groups.csail.mit.edu/mac/users/rauch/worktime/hours_workweek.html

A thirteenth-century estime finds that whole peasant families did not put in more than 150 days per year on their land.

Modern history calls those times the ``Dark Ages''.

>>9
German engineers in World War II had a pattern of failing to consider the limitations of mass production and field repair. Many German weapons systems suffered from inefficient production and limited availability of post-production spare parts because the designers never stopped making changes. Mechanics repairing certain series tanks famously had to cannibalize damaged tanks for spares because new parts sourced from the factories would not fit; it was uncommon to find two tanks that were the same. American designs may have been technically inferior, but they did not suffer as much from this design churn and could be readily produced in volume.