CELLAR WORK AND FOUNDATIONS.
The next visit finds the excavation of the cellar well under way. The earth has been removed, care being taken to make the outside walls conform to the dimensions of the foundation, and the cellar dug to the bottom for a great part of its extent. We proceed at once to examine the nature of the soil and find that while it is in the main a good coarse gravel, there is evidence toward the bottom of a clayey deposit which will hold water, and indeed, in the trenches di rectly under the wall, which are required to be eighteen inches below the bottom of the cellar, there is water standing in sev eral places. Remembering that the specifications have fore seen that the bottom of these trenches should slope to the corner of the cellar, we direct that the slope shall be made toward a Hollow in the lot and that the trench shall be extended until it meets the surface of the ground in the hollow some thirty feet or more from the house. This trench, as well as the slope of the trench under the wall, we must make with a very slight pitch lest the run of the water should wash away the soil under the wall and cause settlements, and for greater security we must see that the lower foot of the wall which, according to the specifications, is " to be laid in dry the trenches", is well laid and not dumped or thrown in. (Fig. S.) These stones should be neither large enough to choke up and prevent the flow of water through the trench nor so small as to be crowded into the ground by the weight of the walls over them, and it will be well in any case to anticipate possible settlement by ram ming the first layer of stones well into the bed of the trench. In a case where the nature of the soil seems to be some what soft or the weight of the building is to be more than usually heavy, it may be desirable to start the walls on broad footing stones carefully bedded upon the bottom. In this cast it will be necessary to make the drain entirely outside of the wall, where it may be made of tile or stones. Indeed, but for the :ulded expense of excavation and the increased cost of large footing stones, this method would be preferable in all cases. (Fig. 9.) If on the completion of the excavating there should be found any wet spots in the cellar bottom, these must lie connected by trenches filled with stone chips, with the main drain under or outside of the wall and in extreme cases the whole cellar bottom under the con crete should be filled with loose stones for about one foot of depth.
Cesspool and Drains. In connection with the excavation of cellar we should take up the matter of a cesspool, provided there is no sewer connection available. Here we will have a choice of meth
ods. In a great many cases where all danger of contamination of wells is obviated by a city or town water service, the cheaper method of a leaching cesspool may be adopted.
Leaching Cesspool. This consists of a circular excavation eight or ten feet in diameter and deep enough to reach to good leaching or absorbent earth, lined with a dry wall of stones laid with open joints, and arched over on top with stone or brick forming a dome made watertight, in the center of which should be set a stone, or an iron manhole. (Fig. 10.) This may be finished at the level of the ground or kept low enough so that it can be sodded over. In good coarse sand or gravel a cesspool of this kind will dispose of the sewage of a house for a great many years, but eventually the pores of the earth will become filled with the deposits and leaching will no longer take place. An effective remedy in this case may be adopted by making an outlet to which a series of pipes laid with open joints may be connected, to distribute the waste throughout a system of branches laid about twelve inches below the surface where it will be absorbed and purified by the soil and growth.
Tight Cesspool. The other form of cesspool is what is known as a tight cesspool and is constructed of hard brick and usually made about six feet in diameter and six feet deep from inlet, with walls and dome eight inches thick and a four-inch bottom, the whole cemented inside and out and made perfectly tight. (Fig. 11.) This cesspool will retain the whole of the deposits and must be either fre quently emptied, or an outlet made of open-jointed pipe as described in connection with the leaching cesspool. This outlet should be below the level of the inlet and should have a bend turned down below the surface so as to remain in the clear water which will be found under the scum which lies on the surface. We find by the specifica tions that our architect has adopted a clever combination of these methods by building two cesspools, the first of which is a small tight cesspool which will retain all the solid and putrefying matter, and con necting this by an overflow pipe with a leaching cesspool built as described. The effect of this is that the tight cesspool will receive all of the solid matter which may be in the sewage, where it can be cleaned out at stated periods; and the overflow being of a wholly liquid nature will pass into the leaching cesspool in a comparatively clear state and will be absorbed entirely by the surrounding earth with no perceptible contamination.