ON THE TREATMENT AND UTILIZATION OF SEWAGE. 447 



In the Second Report will be found a detailed account of the crops grown 

 and the prices obtained. 



Some of the earliest experiments made by the Committee related to " the 

 capacity of earth laid out in beds of 30 feet wide for the absorption of liquid." 

 Three different kinds of gauges were used, and a time was chosen " when the 

 land was in what may be considered an average state of moisture." From 

 these experiments " it resulted that land in the state of moisture which 

 existed on the 19th March [1870] and laid out in beds of 30 feet wide 

 would only absorb, when consolidated, on the surface about 40 tons of 

 liquid per acre, and when stirred to a depth of 9 inches on the previous day, 

 about 90 to 110 tons per acre. By the word 'absorb' is meant that no 

 more than the above quantities could be applied without the formation of 

 puddles at the sides of the beds." (Eeport IT. p. 69.) It was considered 

 that 400 tons per acre was probably the largest quantity that had Qver 

 been applied in any one dressing, and that the assumption that the first 

 dressing aU over the farm was at the rate of 400 tons per acre, the second at 

 that of 200, and the subsequent ones at that of 100 was probably not far from 

 the truth. 



In the Third Eeport, p. 175, will be found a summary of the results of the 

 gaugings of the sewage and effluent water from June 12th, 1870, to July 15, 

 1871 (a period of 399 days). It ai^pears that the average quantity of sewage 

 received from the town per day was 1029 tons, to which something must be 

 added for night-sewage which was allowed to run on to the meadows between 

 the farm and the town. After the 15th of April, when the new tanks were 

 completed and all the sewage received on the farm, the total amount was 

 found to be 1262| tons in the 24 hours, 621 i tons of which came during the 

 working day of ten hours, and the remaining 641^ during the night of 14 

 hours. These quantities, when computed for a day and night of 12 hours 

 each, give day-sewage 729 tons, night-sewage 533|. 



The sewage as pumped contains a certain amount of effluent water that 

 has been brought back into the tanks. The average amount of this diluted 

 sewage pumped was 1182 tons per day. The effluent water discharged, as 

 far as could be estimated, was about 513^ tons per day. The rainfall during 

 the 399 days was 22-64 inches, equal to 2287 tons per acre. 



The experiments on the temperatiu'e of the sewage and effluent water are 

 very important. The temperature of these liquids is very uniform when 

 compared with that of the air, " being lower during extreme heat, and higher 

 during extreme cold." " The ranges and variation over the total period have 

 been : — 



" Atmosphere 2°8-5 to 76 = 47-5 F. 



Town-sewage 43 „ 66 = 23 



Sewage pumped .... 43 „ 67 = 24 

 Effluent water 41 „ 64 = 23 " 



In one week during a severe frost, " when the mean noonday temperature 

 was 28°-5 F., that of the sewage pumped and effluent water was 43° F." 

 (Report III. p. 176.) 



The Fourth Eeport gave the results of the observations carried on from 

 March 25, 1871, to March 24, 1872, both days inclusive ; and gave a more 

 special account of the analyses of the sewage and effluent water during thnt 

 period. The analyses were made of average snniplcp. — that is to say, of 

 samples taken in proportion to the rate of flow of the sewage at the times as 

 iiidicntcd by the gaugings. 



