A SLOP-SINK should be fixed on every alternate floor, if not on every floor of a dwelling-house, on which there are many bedrooms, and where they are likely to be much occupied. Where there is no such convenience, despite all warnings to the contrary, the slops will be emptied down the nearest closet, which will most likely be found out in a disagreeable sort of way by the next person using the closet; for it is not every chambermaid who is thoughtful enough to wipe up any spillings upon the seat.

2. In a small house, where the mistress has more control, and to save expense, the closet on the chamber floor might be constructed to answer the double purpose of water-closet and slop-closet combined; but where this is done, and for certain reasons the pedestal or open closet is objected to, the closet-basin should be constructed with a table-top, and so fitted up that not a drop of slops or a particle of foul matter shall be able to find its way inside the in closure.

3. In my works I prefer to separate slop-sink waste-pipes from soil-pipes, and to " disconnect" them from the soil-drain, either by a disconnecting-trap, such as shown at G, fig. 143, or by a similar trap, but with a mica-valve fixed on the mouth of the fresh-air induct, as circumstances may require. See fig. 114.

In cases where such traps would stand under a window, or near the entrance to the house, and especially so in the case of hospitals, I should seal over the top of the trap and bring fresh air into it from some convenient place, and if circumstances called for it I should fix a mica-valve over the mouth of the induct-pipe, to prevent foul air escaping through it in times of down-draught, etc. *

4. I prefer the separation of slop-sink waste-pipes from soil-pipes, and also their " disconnection " from soil-drains, because a slop-sink has only one seal - the water-seal of its trap between the house and its conduit, and which may be broken either by evaporation, or by a cleansing of the sink. Servants have admitted that they have dipped their flannels into the water held in the trap when cleansing such sinks. In testing the drains of a house a year or two ago (which had been previously tested by more than one engineer and found to be sound, but where there were continued complaints of bad smells), smoke poured into the house through a slop-closet so robbed of its water-seal; and the housemaid confessed to me that she had often dipped her flannel into the closet-trap, when cleansing the basin, and robbed it of its seal, doing it in ignorance.

Fig. 143.

But the connection of the waste-pipe from a slop-sink with that of a soil-pipe is rather a question of the class of closet fixed upon the soil-pipe - leaving out of consideration the question of hot water. For if one seal between the house and the soil-pipe is considered sufficient - as in the "wash-out" and "wash-down" closets - the matters sent through a slop-sink and water-closet being of the same character, or nearly so, there can be no reason why one pipe should not be made to answer the double purpose of slop-sink waste and soil-pipe combined.

5. But where valve-closets are fixed on a soil-pipe, as they are provided with more than one seal (Chap. XXX., Art. 2), there would be good reason for keeping the waste-pipe from a slop-sink out of it, and carrying it down independently of the soil-pipe and disconnecting it from the soil-drain.

Or in the case of a private house, the waste-pipe from the slop-sink and wash-up sink combined might be branched into the waste-pipe from the general sinks, or into the waste-pipe from a bath, as shown in fig. 153; but the bathroom in such cases should have no communication with a bedroom, and the waste-pipe in every such case should discharge with an open end into a disconnecting-trap.

6. In private houses, where hardly anything but liquid slops - from chamber utensils and toilet basins - would be emptied into the slop-sinks, a 2 in. waste-pipe, as shown in fig. 143, would be found to be large enough. And where so required, a wash-up sink of white-ware or fire-clay, for scalding out the chamber utensils, could be fixed, in combination with the slop-sink, as shown at A. Or a slop-sink with a flushing-rim could be fixed, as shown at c, with a syphon flushing-cistern, as shown at v, for flushing out the sink-waste when so required.

7. For hospitals, where excreta, poultices, etc., etc., would be emptied into the slop-sinks, the waste-pipes should be treated as soil-pipes - fixing 3 in., 3 1/2 in., or even 4 in. pipes, as circumstances might require: though a 3 1/2 in. pipe (with trap-ventilation) is large enough for a tier of two or three slop-sinks.

The " McHardy " patent hospital slop-sink is specially constructed for cleansing bed-pans and bottles. The bedpan is put into the sink, which is specially constructed to receive it, when a powerful flush of water is sent up into its interior from the bottom of the sink, and the pan thoroughly cleansed and flushed out; which greatly reduces the risk of the nurse inhaling infected air.

Fig. 144. - Expansion or Telescope Joint.

8. Where hot water draw-off sinks are fixed in combination with the slop-sinks, or hot water is laid on in any way to the sinks, and the waste-pipes are of lead and fixed outside - as should be the case where possible - telescope joints, or expansion joints, as shown in fig. 144, should be made upon the pipes, to allow them to expand and contract without breaking. Some joints which I had made upon 2 in. bath-wastes and 3 in slop-sink waste-pipes eight or nine years ago, were found to be sound and good when last tested, and water at a very high temperature has often been sent through the pipes.