Washing Machines and Dog-Powers

Bloomberg has a piece on the long, long history of washing machines, as in 250 years + long.  (If I remember correctly, Hans Rosling credited the machines as one of the bigger improvements in our living standards.)  My mother would recall that the family dog would disappear on Mondays because that was wash day and he was expected to toil on the "dog power" to run the washing machine.  See this for an image and description.