Allowing a fall of, say, 1 in 10, it is evident that for every foot above ground at which a waste pipe terminates it is possible to deliver the waste on to the surface of the ground at 10 feet from the house. Thus the bedroom sink waste at a height of 10 feet above ground level might be made, if so desired, to deliver its waste 100 feet from the house. It is often necessary to take the waste pipes from the first floor over the path surrounding the house. This is easily accomplished without causing any unsightliness by placing an arch over the path. Such arches may be of galvanised iron for a cottage, or of masonry for a mansion, and are soon hidden by creepers. Figs. 24 and 25 illustrate how this principle may be carried out; in the one case by a rustic arch costing a few shillings, and in the other case by a porch and arcading of a more ambitious description. Fig. 24 is from a photograph of an arch in actual use. Fig. 25 has been furnished by Mr. Cutler. [Illustration: Fig. 24.—Rustic Arch.] [Illustration: Fig. 25.—Use of Arch for getting Waste Water clear of House.] When pipes are provided with a rapid fall there is little tendency for water to freeze in them, but in severe climates it might be necessary to pack the pipes. The waste pipes of kitchen and pantry sinks are, in London, almost always below ground level, it being the custom to place the kitchen and offices in an underground basement; and I have known London architects who have provided country houses with similar abominations, so that the sewage of a basement has to be lifted before it can be properly treated. If this evil is to be avoided, it is essential that the waste pipes of kitchen and pantry sinks terminate at least two feet above ground level. This is a minimum, and if a greater fall can be obtained, so much the better. Kitchen and pantry waste is full of dissolved and suspended matter, and a careless cook will throw down the sink enough food to keep a pig or a dozen fowls. This waste is very prone to become offensive, and it is advisable that it be thoroughly strained before flowing away. Not only should the waste pipe have a fixed and immovable strainer below the plug, but a sink basket should be used, and the waste should be still further strained in a manner to be presently described. _2. No stagnation must anywhere be permitted along the line of slop-drainage._