a ribbed bulbous washing tub in the traditional form

The traditional English galvanised steel Dolly Tub is a classic piece of domestic laundry equipment, once a staple in many British homes. Named after the “dolly” — a wooden tool used for agitating clothes it was used for hand-washing  before the advent of washing machines. To use it, clothes would be soaked in water with soap or detergent, and the dolly would be used to stir and agitate the laundry, helping to remove dirt.