We have hitherto considered only those fixtures which receive foul water unmixed with discharges from the human system. Slop sinks and slop hoppers, as well as water closets and urinals, intended to convey to the drain these foul discharges, are more liable to become filthy outside and inside, unless carefully attended to.

Slop hoppers are provided on bedroom floors to enable servants to empty chamber slops into them. They must be flushed, after each use, by a sufficient quantity of clean water from a cistern, or else at frequent intervals by automatic flush tanks, to expel the foul water from the trap and to wash the inner sides of the hopper bowl or sink. Considering the character of the foul water poured into such vessels, an efficient flush is fully as necessary for them as it is for water closets or urinals.

Slop sinks are made either of enameled cast-iron or of earthenware. Their outlet should always be provided with a fixed strainer to prevent any obstruction of the trap or the soil pipe by carelessly introduced articles, such as scrubbing brushes, etc.

Instead of a deep sink a combination of a sink and a hopper, such as Merry's slop-hopper sink, is sometimes used, and, if provided with a strainer, it will answer very well.

An earthen bowl, with improved flushing rim, placed on top of an iron or lead hopper, will make a cleanly device. The neatest arrangement is a slop sink, made in one piece of earthenware, enlarged at the top to a square sink, and provided with a flushing rim and liberal supply of hot and cold water.

Slop sinks and hoppers should be treated in their external finish similar to kitchen sinks and water closets. Air and light should find easy access to them; there should be no tight woodwork around the apparatus with the usual amount of dust aud untidiness. The floor may be of white tiles or of cement, and the walls may be laid with tiles or with enameled bricks.

If water closets without movable parts (hopper and washout closets) are fitted up without woodwork (except the seat) they may also serve the purpose of a slop sink, provided that the flush is not forgotten after emptying slops. The practice of using pan, valve or plunger closets, to get rid of chamber slops, is decidedly objectionable. These closets are most always encased in woodwork, which becomes impregnated with the foul water, carelessly emptied and often spilled. In the case of valve closets, the overflow pipe from the bowl is fouled and the same is true for plunger chamber and overflow of plunger closets.