388 ENGINEERING ON THE FARM 



toilet fixtures are recommended, and should be installed 

 wherever possible; but, in order to make a modern bathroom 

 sanitary, some efficient method is necessary for the disposal 

 of all waste which is carried by liquids from the house. 



Cesspool. A common practice has been to drain this 

 waste into a pit or cesspool near the house, a cesspool being 

 an opening in the ground, either curbed with lumber or walled 

 with brick. If the soil is porous and permits the water to 

 percolate with fair rapidity, the liquid drains out, and the 

 solid matter left will fill up the pool. If the soil is imper- 

 vious, the liquid will not escape as rapidly as it accumulates, 

 and in a short time will be flowing over the surface. Many 

 cesspools which work satisfactorily for a few months or two 

 or three years finally fail to work, and overflow because of 

 the clogging of the soil by the solid matter held in solution. 

 When this occurs, it is necessary to construct a new cesspool. 

 The cesspool saturates the surrounding ground for a long 

 distance with disease germs, which in time may be carried 

 into the house water supply. However, reports come in 

 occasionally regarding cesspools which have worked for 

 several years, and to all appearances were perfectly satis- 

 factory. If such a pool is examined, it will be found that 

 the conditions are somewhat unusual. The porosity of the 

 earth a short distance below the surface is such that the 

 liquids escape at approximately the same rate as they enter, 

 the lower part of the pool being practically impervious. 

 Consequently the liquids are held at a uniform depth. This 

 condition of the pool, combined with other conditions, 

 favors the growth of certain bacteria carried in house 

 sewage. These bacteria, working in the sewage, cause all 

 the solid matter to be separated into liquids and gases. The 

 gas escapes into the air and the liquid disappears in the soil. 

 The cesspool, owing to favorable conditions, is acting as a 

 septic tank and gives satisfactory results. 



Septic tanks. It has been found that, if sewage can be 

 held for a given length of time under proper regulations 



