All natural shapes of ground must necessarily fall under one of these descriptions, viz., convex, concave, plane, or inclined plane, as represented in the following sections, plate No. X. [our fig. 24.] I will suppose it granted that, except in very romantic situations, all the rooms on the principal floor ought to range on the same level; and that there must be a platform, or certain space of ground, with a gentle descent from the house every way. If the ground be naturally convex, or what is generally called a knoll, the size of the house must be adapted to the size of the knoll:* this is shewn by the small building A, supposed to be only one hundred feet in front, which may be placed upon such an hillock, with a sufficient platform round it; but if a building of three hundred feet long, as B, B, should be required, it is evident that the crown of the hill must be taken off, and then the shape of the ground becomes very different from its original form: for although the small house would have a sufficient platform, the large one will be on the brink of a very steep bank at C; and this difficulty would be increased by raising the ground to the dotted line D, to set the large house on the same level with the smaller one. It therefore follows, that if the house must stand on a natural hillock, the building should not be larger than its situation will admit; and where such hillocks do not exist in places proper for a house in every other respect, it is sometimes possible for art to supply what nature seems to have denied: but it is not possible in all cases; a circumstance which proves the absurdity of those architects who design and plan a house, without any previous knowledge of the situation or shape of the ground on which it is to be built.-Such errors I have had too frequent occasion to observe.
*[There is a recent instance of a house adapted to the shape of a beautiful knoll at Courteen Hall, where an elegant mansion, with three fronts, has been lately built, under the direction of S. Saxon, Esq.]