I've been looking at some information on the old 'court' style housing in Birkenhead around the middle to late 19th century. They were mostly overcrowded, insanitary slums which had shared outside privies. Among the various privies listed for some properties are ash pits, water closets and tumbler closets. Does anyone know what a tumbler closet was?

Have a look here-- click me

They had closets with one trough, a tank slowly filled with water, when reaching a certain level, it capsized/tumbled, releasing water in to the trough. In turn emptying the contents in to the drains. It removed the responsibility of flushing from the user. The courts and the lower order housing had closets, 3 or 4 and one trough to cater for perhaps 20 dwellings. No set amount.

Thanks for both your answers, and especially to Bert for the technical explanation. On all levels, life was pretty grim back then for the lower orders.