accumulation of solid filth, caused by overflow from the middens." (Middens and middensteads both refer to dunghills, ash pits, or refuse heaps.) Such problems forced the city authorities to consider other methods of dealing with human excretion. Although the water closet was used in wealthy homes, concerns over river pollution, costs and available water supplies meant that most towns and cities chose more labour-intensive dry conservancy systems. Manchester was one such city and by 1877 its authorities had replaced about 40,000 middens with pail and midden closets, rising to 60,000 by 1881. The soil surrounding the old middens was cleared out, connections with drains and sewers removed and dry closets erected over each site. A contemporary estimate stated that the installation of about 25,000 pail closets removed as much as of urine and accompanying faeces from the city's drains, sewers and rivers. The midden closet was a development of the privy, which had evolved from the primitive "fosse" ditch. Midden closets were still used in the latter part of the 19th century but were rapidly falling out of favour. A Mr Redgrave, in a speech to the Institution of Civil Engineers in 1876, said that the midden closet represented "... the standard of all that is utterly wrong, constructed as it is of porous materials, and permitting free soakage of filth into the surrounding soil, capable of containing the entire dejections from a house, or from a block of houses, for months and even years". The 1868 Rivers Pollution Commission reported two years later: "privies and ashpits are continually to be seen full to overflowing and as filthy as can be... These middens are cleaned out whenever notice is given that they need it, probably once half-yearly on an average, by a staff of night-men with their attendant carts." Midden closets were, therefore, generally insanitary and were also difficult to empty and clean. Later improvements, such as a midden closet built in Nottingham, used a brick-raised seat above a concave receptacle to direct excreta toward the centre of the pit—which was lined with cement to prevent leakage into the surrounding soil. This closet was also designed with a special opening through which deodorising material could be scattered over the top of the pit. A special ventilation shaft was also installed. The design offered a significant improvement over the less advanced midden privy, but the problems of emptying and cleaning such