--------+----------+------------------------------------------------ | Quantity | Siphon chamber. Number |of sewage +-------+--------+--------+----+----+----+------- of | in 24 |Length.| Depth. | Width. | A. | B. | C. | D. persons.| hours. | | | | | | | --------+----------+-------+--------+--------+----+----+----+------- | Galls. |Ft. In.| Ft. In.| Ft. In.| In.| In.| In.| In. 5 | 180-280 | 5 0 | 2 8 | 2 0 | 3 | 4 | 15 | 18-1/4 10 | 320-480 | 8 0 | 2 8 | 2 6 | 3 | 4 | 15 | 20-1/4 15 | 520-680 | 8 8 | 2 10 | 3 0 | 4 | 4 | 17 | 20-1/4 20 | 720-960 |10 0 | 2 10 | 3 6 | 4 | 4 | 17 | 20-1/4 --------+----------+-------+--------+--------+----+----+----+------- --------+---------+---------+--------+--------+---------+------------- |Quantity | | | | |Reinforcement | of | | | | | in top slab Number | sewage | | | | | (strip of of | in 24 |Concrete.| Cement.| Sand. | Stone. | heavy stock persons.| hours. | | | | | fencing). | | | | | +-------+------ | | | | | |Length.|Width. --------+---------+---------+--------+--------+---------+-------+------ | Galls. | Cu. yds.| Bbls. |Cu. yds.| Cu. yds.| Ft. | In. 5 | 180-280 | 3 | 4-1/2 | 1-1/3 | 2-2/3 | 10 | 3 10 | 320-480 | 4-1/4 | 6-1/4 | 2 | 3-3/4 | 14 | 3 15 | 520-680 | 6-2/3 | 9-3/4 | 3 | 6 | 15-2/3| 4 20 | 720-960 | 8 | 12 | 3-1/2 | 7 | 17-1/2| 5 --------+---------+---------+--------+--------+---------+-------+------ =Siphons.=--Reference has already been made to the vital importance of air in sewage filtration. If the spaces within a filter or soil are constantly filled with water, air is excluded, and the action of the filtering material is merely that of a mechanical strainer with its clogging tendency. The purpose of a siphon is twofold: (1) To secure intermittent discharge, thus allowing a considerable period of time for one dose to work off in the soil and for air to enter the soil spaces before another flush is received; (2) to secure distribution over a larger area and in a more even manner than where the sewage is allowed to dribble and produce the conditions of the old-fashioned sink drain--namely, a small area of water-logged ground.