ON THE TREATMDNT AND UTILIZATION Oi' SEWAGE. 



117 



for six hoiir3 at a time, leaving an interval of eigliteen hours for rest and 

 aeration of the soil. . 



The surface of the land was cultivated to a depth of from 16 to lb inches, 

 and laid up in ridges in order that the sewage might run down the furrows, 

 while the ridges were ijlantod with cabbages and other vegetables. 



The Committee lias adopted the same mode of investigation in this as in 

 other cases, and the following is a description of their operations. 



It was thought addsablc in this, as in other examinations of se\yage-farms, 

 that inspections should be made at two seasons of the year,— in winter, when 

 the laud is saturated with rain or frozen, and again in summer during dry 

 weather, when there is the greatest activity in vegetable life. 



The first examination of the farm was made in January last, in very wet 

 weather, when the system was in operation as above described. Samples, 

 extending over a period of seven days, were collected of the sewage as it 

 entered the farm, and of the effluent water from the outfall drain before de- 

 scribed. Gaugings were taken of the flow of both the sewage and efliuent 

 water for eight days, with the following results : — 



It will be seen that the quantity of effluent water discharged was more 

 than double the quantity of .sewage ; and as the rainfall, though considerable, 

 could not possibly account for such an increase, it was felt necessary to look 

 elsewhere for its cause. It Avas ascertained from the Surveyor to the Local 

 Board that the bed of the river Taft' is 4 feet 7 inches above the bottom of the 

 effluent drain ; and observation proved that when the water in the river rose 

 that of the drain rose also, and on the river-water subsiding the same thing 

 occurred in the drain. 'From this it became evident that a filtering eommu- 

 nicatiou exists between the river and the drains, the natiu'e of the soil 

 rendering this very probable. To further test the matter, trial holes were dug 

 in a field adjoining, and to the north of the filtering-beds, when it was found 

 that the same thing occurred, the water collected in them rising and falling 

 •with that in the river. 



It should be stated that some gaugings of the flow of the sewage were taken 

 in November 1871, by Mr. Harper, the Surveyor to the Local Board, which, 

 as will be seen, agree closely with those taken for the Committee. 



