2 SEWAGE AND ITS PURIFICATION 



and drinking, and, having access generally to an ample amount 

 of open and porous soil, employed what we may call the earth 

 system. Following the aggregation into settlements, it was 

 early found necessary to set aside special places for the recep- 

 tion of refuse ; hence the midden heaps that have been widely 

 discovered. After a time, for human excreta ditches or trenches 

 were dug, from which the products of decomposition either 

 sank into the surrounding soil or found an outlet to some 

 watercourse. In many cases the trenches were at length filled 

 in with earth, over which a rank vegetation grew, and the soil 

 became gradually purified, a plan which is still followed in the 

 case of temporary camps and in Eastern villages. At a later 

 stage, when the progress of civilization necessitated the use for 

 washing and cooking of a large quantity of water, isolated 

 inhabitants found it difficult to dispose of the liquids ; therefore 

 great pits were dug to receive them, and to keep the rain out 

 were roofed over with beams and earth. At a still later period 

 these excavations were lined with brick, arched over, and con- 

 nected with the houses by brick or flagstone drains. No cement, 

 as a rule, was used in the construction, as it was found that if 

 the sewage sank into the earth less frequent emptying was 

 required. Moreover, if the receptacle or cesspool were made 

 air and water-tight by cement, it was necessary to provide a 

 vent for the large quantity of gas that was generated in the 

 decompositions. I can record a case where a cemented cess- 

 pool in the North of England regurgitated a large quantity of 

 sewage into the cellars of the house, although the pit had been 

 recently erected, and was by no means full. In other cases 

 unventilated cesspools have filled the basement of dwellings 

 with sewer gas. 



For houses in isolated positions the cesspool till lately was 

 the only available means of sewage disposal, and architects and 

 others spent considerable time and skill upon its design in the 

 early Victorian period, when sanitary progress first drew atten- 

 tion to its importance. I give the following as an example of 

 its successful use, which is interesting on account of its being 

 antecedent both to the French " automatic scavenger," to be 

 described in a subsequent chapter, and to the modern " septic 

 tank ": 



In 1858 a large school in Derbyshire, situate on the top of 

 a lofty hill, surrounded by its own land, but at a distance of 

 two miles from a small river which ran through other property. 



