10 



and undulating contour. For special effects, of course, other combinations are 

 necessary. 



Lawns to the rear or at the side of a house usually look best in a modeling which 

 is generally concave. This contour, in contrast to convex modeling, tends to 

 increase the apparent size of these areas. The motif of a lawn is an open center 

 with solid boundaries, and its spaciousness may be accentuated by means of a 

 concave modeling. Applying the principles of concave modeling just explained, 

 if the low part of a lawn is made nearer to the far boundaries than to the house, 

 the effect of apparently greater depth is produced. The rear lawns adjoining 

 small city or suburban houses may be given a slight degree of concavity by little 

 or no actual hollowing of the grades, but rather by filling to raise the borders 

 about a foot or perhaps slightly less. Even this slight degree of concavity is 

 effective and pleasing. 



There are other details pertaining to grading which contribute greatly toward 

 practical construction and toward finished appearances. Grass slopes or terraces, 

 if not conventional, should, in most cases, have what is called an "O G profile," 

 that is, a reverse curve; and the radius of curvature at the top should be less, 

 while that at the base of the slope should be greater. This curvature affords 

 stability and is by far the best detail for what is commonly known as an 

 "informal slope.' The per cent of slope should preferably not average nore than 

 one foot of rise to two feet of width. When steps are built into a terrace, the 

 slanting surface of the terrace should conform to the ratio of the step s. Steeper 

 embankments are of course necessary at times, and usually these are densely 

 planted with vegetation that will prevent washing. Formal terraces should 

 comply with the suggestions just mentioned as appropriate to the percentage 

 of slope. Grass ramps used in place of steps to connect different levels are usually 

 made as a formal terrace, but in a ratio of one foot of rise to eight feet of width. 

 This feature serves to draw more closely together the levels so connected, and pos- 

 sesses the advantage of greater simplicity. Ramps may be either conventionalized 

 or treated in an informal way. 



Walls can be used between different levels, and while the expense of construct- 

 ing them is greater than for terracing, they occupy less space. In many instances 

 "dry masonry" may be employed in the walls. This is less expensive than solid 

 masonry laid in cement, and requires less foundationing. Dry walls, to be stable, 

 must usually be laid to considerable "batter," and cannot be as narrow as are 

 walls of cemented masonry. The character of each type of wall is quite different, 

 and one should not determine on one or another from a consideration of cost alone. 

 If walls are employed, very likely steps will also be needed, and this question should 

 be studied carefully. In the first place, one should realize that the ratios satis- 

 factory for indoor stairs will not prove equally good about the garden, in the en- 

 trance walk, or even at the porches and the doorways. The conditions affecting 

 steps out-of-doors are entirely different from those inside the house. Most out- 

 of-doors steps have a decorative value as well as a practical one ; they usually occur 

 in short rather than long flights, and they are wider, and rarely is there a ramp 

 or a hand rail within reach for support. As a rule a good ratio for out-of-door steps 

 is six inches rise to fourteen inches tread, with perhaps a quarter of an inch "wash" 

 allowed on each tread. If one wishes to express a very close relation between two 

 levels in a garden or between terraces and gardens, the same rise may be used 



