If gravel can be obtained without too much expense, it may be used with excellent results to a depth of from one to three inches, according to the porosity of the subsoil,--more being needed where the ground is inclined to become soft. In using gravel it is best either to screen it, using the coarser parts below and the finer parts at the surface, or, after applying it, to add a thin layer of earth, barely sufficient to fill its spaces,--to "bind" it so as to give it a firm and solid consistency. Loose and rattling gravel makes a handsome walk to look at, but an unpleasant one to walk upon. Nothing is more agreeable than well-trodden, dry, root-bound earth, as where grass has been worn away by frequent use; but this becomes at once objectionable on being saturated with rain or moistened by melting frost. [Illustration: FIG. 1.] It is a common impression, that all thoroughly good foot-paths must be dug out to a considerable depth, filled with loose stones, and dressed at the top with some good finishing material; but this is not necessary even for the best work. The great point is to secure a thorough draining of the sub-stratum, so that there shall be no rising of ooze-water from below, and so that the ground shall be free from such saturation as to cause heaving during frost. This condition may be secured by a suitable draining of the ground immediately under the walk, and by the use of a well-compacted and tightly-bound surface covering of such form as to shed or turn away rain-water. Figure 1 (p. 31) shows the cross section of a foot-path six feet wide on slightly sloping ground, where we have to apprehend an oozing of subsoil water from the land at the highest side. The centre of the walk is slightly crowning,--say one inch higher than the sides,--so that rain falling upon it will flow readily toward the grass-border at either side. To prevent the ponding of water at the sides when the ground is frozen, the surface of the walk at its edges should be well above the level of the adjoining ground; but it may be necessary under some circumstances to furnish, here and there, a channel or surface-gutter across the walk, to allow the accumulation at the higher side to escape. Rarely will deep gutters at the sides be necessary or desirable. If the walk is laid at a sufficient height to turn water on to the adjoining ground instead of receiving water from this, it will be easy to keep it dry. We will assume that the path in question is to be made over a tenacious clay soil, with a considerable oozing from the hillside,--the most unfavorable condition that can be found, especially in cold climates. The first thing to be secured is the cutting-off of the subsoil water from the hill. This may be done by digging a trench as narrow as possible,--six inches will be better than more, as requiring less filling material,--to a depth of three feet. In the bottom of this drain lay a common land-tile drain, with collars at